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  • Inhibition of lignification of Zizania latifolia with radio frequency treatments during postharvest
    BMC Chem. (IF 2.284) Pub Date : 2020-01-18
    Changwen Ye; Chen He; Bowen Zhang; Lixuan Wang; Lufeng Wang

    Zizania latifolia is easily lignified after harvesting, leading to the degradation of food quality and commercial value. Thus, this study evaluated the effect of radio frequency (RF) treatments on lignification inhibition of Zizania latifolia. The results showed that the lignin content of Zizania latifolia treated with RF decreased significantly compared with the control group. At the 7th day of storage, the phenylalanine ammonia lyase activity of the 90 W RF treatment group decreased by 52.9% compared with the initial value. The activities of peroxidase and polyphenol oxidase in the stems of Zizania latifolia were significantly (p < 0.05) decreased after RF treatments. Besides, a decrease in conversion rate of O2− and H2O2 to downstream products was observed, indicating that the related invertases were inhibited by RF treatment. All of these showed that RF treatments contribute to inhibit or delay the lignification of Zizania latifolia, providing a better taste and quality for products.

  • Preparation of high-capacity magnetic polystyrene sulfonate sodium material based on SI-ATRP method and its adsorption property research for sulfonamide antibiotics
    BMC Chem. (IF 2.284) Pub Date : 2020-01-14
    Huachun Liu; Bolin Gong; Yanqiang Zhou; Zhian Sun; Xiaoxiao Wang; Shanwen Zhao

    A novel polystyrene sulfonate sodium (PSS) magnetic material was prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The starting materials were brominated magnetic material as the carrier and macroinitiator, sodium styrene sulfonate (NaSS) as the monomer, and cuprous bromide/2,2′-dipyridyl as the catalyst system. The PSS material was characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis, transmission electron microscope (TEM), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and a vibrating sample magnetometer (VSM). The adsorption properties of the material were then investigated on sulfa antibiotics. The kinetic and thermodynamic parameters were determined in adsorption of sulfamethazine (the smallest molecular-weight sulfonamide). The adsorption amount of sulfamerazine free acid (SMR) was found to increase with the initial concentration and temperature of SMR in solution. The adsorption effect was maximized at an initial concentration of 0.6 mmol/L. The static saturation adsorption capacity of the material was 33.53 mg/g, Langmuir and Freundlich equations exhibited good fit. The thermodynamic equilibrium equation is calculated as ΔG < 0, ΔH = 38.29 kJ/mol, ΔS > 0, which proves that the adsorption process is a process of spontaneous, endothermic and entropy increase. Kinetic studies show that the quasi-second-order kinetic equation can better fit the kinetic experimental results, which is consistent with the quasi-second-order kinetic model. The experimental results of kinetic studies were well fitted to a quasi-second-order kinetic equation. High performance liquid chromatography (HPLC) of an actual milk sample treated by the PSS magnetic material confirmed the strong adsorption of SMR from milk.

  • Magnetic γFe2O3@Sh@Cu2O: an efficient solid-phase catalyst for reducing agent and base-free click synthesis of 1,4-disubstituted-1,2,3-triazoles
    BMC Chem. (IF 2.284) Pub Date : 2020-01-07
    Fereshteh Norouzi; Shahrzad Javanshir

    A hybrid magnetic material γFe2O3@Sh@cu2O was easily prepared from Shilajit (Sh) decorated Fe3O4 and copper acetate. The prepared magnetic hybrid material was fully characterized using different analysis, including Fourier transform infrared (FT-IR), X-ray diffraction (XRD), inductively coupled plasma (ICP), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) thermal gravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET). All these analysis revealed that during coating of Fe3O4@Sh using copper salt (II), synchronized redox sorption of CuII to CuI occurs at the same time as the oxidation of Fe3O4 to γFe2O3. This magnetic catalyst exhibited excellent catalytic activity for regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles via one pot three-component click reaction of sodium azide, terminal alkynes and benzyl halides in the absence of any reducing agent. High yields, short reaction time, high turnover number and frequency (TON = 3.5 * 105 and TOF = 1.0 * 106 h−1 respectively), easy separation, and efficient recycling of the catalyst are the strengths of the present method.

  • A new phenothiazine-based selective visual and fluorescent sensor for cyanide
    BMC Chem. (IF 2.284) Pub Date : 2020-01-07
    Fatimah A. M. Al-Zahrani; Reda M. El-Shishtawy; Abdullah M. Asiri; Amerah M. Al-Soliemy; Khloud Abu Mellah; Nahed S. E. Ahmed; Abdesslem Jedidi

    A new donor-π-acceptor derived from phenothiazine, namely 2-(2-((10-hexyl-10H-phenothiazin-3-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (PTZON) was synthesized and fully characterized, and its potential as a fluorescent sensor for cyanide anion was investigated. The PTZON showed a visible absorption band at 564 nm corresponds to an intramolecular charge transfer (ICT) and an emission band at 589 nm in CH3CN/H2O. The results of cyanide anion titration revealed ratiometric changes in both absorption and fluorescence spectra as a result of the nucleophilic addition of cyanide anion via Michael addition. The optical studies, FT-IR spectra, NMR, high-resolution mass, and DFT calculations confirmed the sensing mechanism. The selectivity of PTZON as a cyanide anion fluorescent sensor was proved in mixed solvent solutions, and the sensitivity was as low as 0.011 µM, which is far lower than the value allowed by the United States Environmental Protection Agency for drinking water (1.9 µM). Also, the detection limit of PTZON was assessed to be 3.39 μM by the spectrophotometric method. The binding stoichiometry between PTZON and cyanide anion was found to be 1:1 as evidenced by mass spectra. TLC silica-coated plates test strips demonstrated the fluorescent detection of cyanide anion.

  • Facile synthesis and antiproliferative activity of new 3-cyanopyridines
    BMC Chem. (IF 2.284) Pub Date : 2019-12-28
    Hassan M. Abdel-aziz; Sobhi M. Gomha; Abdelaziz A. El-Sayed; Yahia Nasser Mabkhot; Abdulrhman Alsayari; Abdullatif Bin Muhsinah

    Pyridines have been reported to possess various pharmacological activities. Sodium 3-oxo-3-(2-oxo-2H-chromen-3-yl)prop-1-en-1-olate (2) and sodium 3-oxo-3-(3-oxo-3H-benzo[f]chromen-2-yl)prop-1-en-1-olate (7) were prepared and reacted with 2-cyano-N’-(1-aryl(heteryl)ethylidene)acetohydrazides 3a–d to produce 2-oxo-1,2-dihydropyridine-3-carbonitrile derivatives 5a–d and 9a–d, respectively, in good yields. Also, 3a–d reacted with sodium (2-oxocyclopentylidene)methanolate (11a) or sodium (2-oxocyclohexylidene) methanolate (11b) to yield 2-oxo-tetrahydro-1H-cyclopenta[b]pyridine-3-carbonitriles 13a–d and 2-oxo-hexahydroquinoline-3-carbonitriles 13e–h, respectively. The mechanisms that account for the formation of the products are discussed. Additionally, the structures of all the newly synthesized products are confirmed, based on elemental analysis and spectral data. Several of the newly synthesized compounds are evaluated for their antitumor activity against HEPG2 and their structure activity relationship (SAR) was studied. The results revealed that the pyridine derivatives 5c and 5d (IC50 = 1.46, 7.08 µM, respectively) have promising antitumor activity against liver carcinoma cell line (HEPG2), compared to the reference drug, doxorubicin.

  • Recent advances in the use of benzimidazoles as corrosion inhibitors
    BMC Chem. (IF 2.284) Pub Date : 2019-12-23
    Maria Marinescu

    Benzimidazole, a key heterocycle in therapeutic chemistry, and its derivatives, are recently mentioned in the literature as corrosion inhibitors for steels (CS, MS), pure metals (Fe, Al, Cu, Zn) and alloys. Benzimidazoles are good corrosion inhibitors for extremely aggressive, corrosive acidic media such as 1 M HCl, 1 M HNO3, 1.5 M H2SO4, basic media, 0.1 M NaOH or salt solutions. Benzimidazole derivatives act as mixed type inhibitors, exhibiting stronger inhibitive effect on the cathodic reaction than on the anodic one. These review highlights recent research in the field of benzimidazole compounds that their role as corrosion inhibitors, the structure of the compounds, electrochemical studies, the experimental conditions, the proposed mechanisms as well as the quantum theoretical studies that predict the structure of the compounds with inhibition properties.

  • Pressurized hot water extraction of hydrosable tannins from Phyllanthus tenellus Roxb.
    BMC Chem. (IF 2.284) Pub Date : 2019-12-21
    Noor Hidayah Mohd Jusoh; Atiqah Subki; Swee Keong Yeap; Ken Choy Yap; Indu Bala Jaganath

    Safety, environmental and economic setbacks are driving industries to find greener approaches to extract bioactive compounds from natural resources. Pressurized hot water extraction (PHWE) is among the solvent free and efficient methods for extracting bioactive compounds. In this study, the suitability of PHWE for extracting bioactive compounds such as phenolics, hydrolysable tannins and flavonoids from Phyllanthus tenellus was investigated by UPLC-qTOF-MS. Solvent properties of water are significantly increased through imposing temperature at 121 °C and pressure at 15 p.s.i. Pressurized hot water extraction obtained 991-folds higher hydrolysable tannins than methanol extraction. The extraction yields of hydrolysable tannins with PHWE was almost double of absolute methanol extraction.

  • Evaluation of an online, real-time, soft-photon ionisation time-of-flight mass spectrometer for mainstream tobacco smoke analysis
    BMC Chem. (IF 2.284) Pub Date : 2019-12-21
    Jenni Hawke; Graham Errington; Matthias Bente von Frowein

    Mainstream tobacco smoke is a complex and dynamic aerosol, consisting of particulate and vapour phases. Most approaches to determine mainstream smoke toxicant yields are based on offline techniques that limit the opportunity to observe in real time the processes leading to smoke formation. The recent development of online real-time analytical methods offers many advantages over traditional techniques. Here we report the LM2X-TOFMS (Borgwaldt GmbH, Germany), a commercial instrument that couples a linear smoking engine with a time-of-flight mass spectrometer for real-time per-puff measurement of the vapour phase of mainstream cigarette smoke. Total cigarette and puff-by-puff (μg/puff) yields were evaluated, in line with International Council of Harmonisation recommendations, for seven smoke toxicants: acetaldehyde, acetone, 1,3-butadiene, 2-butanone, benzene, isoprene and toluene. Measurements were unaffected by small system changes including replacing the sampling capillary or time of day (all P > 0.05), indicating that the LM2X-TOFMS is rugged. Control charts showed that the system has good stability and control. Analysis of certified gas mixtures of six concentrations of each analyte showed a highly linear response for all seven analytes (R2 = 0.9922–0.9999). In terms of repeatability, the lowest variation was observed for isoprene with a coefficient of variation (CV) of < 6% for each concentration. Acetaldehyde showed the highest CV, increasing from 8.0 to 26.6% with decreasing gas concentration. Accuracy was analysed in terms of relative error, which was ± 16% for six of the analytes; however, the relative error for acetaldehyde was (− 36.2%), probably due to its low ionisation efficiency under the instrument’s vacuum ultraviolet lamp. Three cigarette products (reference and commercial) with different ISO tar levels were analysed by the LM2X-TOFMS puff by puff under ISO regulatory smoking conditions. The relative standard deviation based on average yield per cigarette for each analyte in each product (summed puffs per product, n = 30) ranged from ≤ 9.3 to ≤ 16.2%. Measurements were consistent with published data per cigarette. In conclusion, the LM2X-TOFMS is suitable for determining the vapour-phase yields of seven analytes on a real-time, puff-by-puff basis, and can be utilised for both fast screening (qualitative) and quantitative measurements of mainstream cigarette smoke.

  • Contribution of aroma compounds to the antioxidant properties of roasted white yam (Dioscorea rotundata)
    BMC Chem. (IF 2.284) Pub Date : 2019-12-19
    Ola Lasekan; Li Shing Teoh

    The aroma chemistry and the contribution of the aroma compounds to the anti-oxidative properties of roasted yam have yet to be characterized. The growing popularity of roasted yam in regions where they are being consumed calls for a concerted effort to elucidate their aroma chemistry as well as their anti-oxidative properties. The aroma compounds in roasted white yam (Dioscorea rotundata) were isolated and identified using static headspace-gas chromatography-mass spectrometry (SH–GC–MS) and gas chromatography–olfactometry (GC–O). In addition, the anti-oxidative activities of the most abundant volatile heterocyclic compounds (2 pyrroles, 4 furans and 3 pyrazines) were evaluated on their inhibitory effect towards the oxidation of hexanal for a period of 30 days. Twenty-nine aroma-active compounds with a flavour dilution (FD) factor range of 2–256 and an array of odour notes were obtained. Among them, the highest odour activities (FD ≥ 128) factors were determined for 2-acetyl furan and 2-acetylpyrrole. Other compounds with significant FD factors ≥ 32 were; 2-methylpyrazine, ethyl furfural, and 5-hydroxy methyl furfural. Results of the anti-oxidative activity showed that the pyrroles exhibited the greatest antioxidant activity among all the tested heterocyclic compounds. This was followed by the furans and the pyrazines which had the least antioxidant activity.

  • A facile and one-pot synthesis of new tetrahydrobenzo[b]pyrans in water under microwave irradiation
    BMC Chem. (IF 2.284) Pub Date : 2019-11-26
    Mandlenkosi Robert Khumalo; Surya Narayana Maddila; Suresh Maddila; Sreekantha B. Jonnalagadda

    Eleven new tetrahydrobenzo[b]pyran derivatives were synthesized via a three component reaction of different aromatic aldehydes, methyl cyanoacetate and 1,3-cyclohexadione, with water as solvent under catalyst-free microwave irradiation. The structures of all the new molecules were well analysed and their structures established by using various spectral techniques (1H NMR, 13C NMR, 15N NMR and HRMS). Various advantages of reported protocol are the ease of preparation, short reaction times (10 min), aqueous solvent and excellent yields (89–98%). Additionally, this method provides a clean access to the desired products by simple workup.

  • Antimicrobial, antioxidant and cytotoxic evaluation of diazenyl chalcones along with insights to mechanism of interaction by molecular docking studies
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Harmeet Kaur; Jasbir Singh; Balasubramanian Narasimhan

    In continuation of our work, new diazenyl chalcones scaffolds (C-18 to C-27) were efficiently synthesized from substituted acetophenone azo dyes (A–E) by base catalyzed Claisen–Schmidt condensation with different substituted aromatic/heteroaromatic aldehydes. The synthesized chalcones were assessed for their in vitro antimicrobial potential towards several pathogenic microbial strains by tube dilution method and further evaluated for antioxidant potential by DPPH assay. These derivatives were also assessed for the cytotoxicity towards the human lung cancer cell line (A549) and normal cell line (HEK) by MTT assay. The most active antimicrobial compounds were docked using Schrodinger v18.1 software with the various potential bacterial receptors to explore the mechanism of interaction. The derivative C-22 exhibited high antibacterial activity with very low MIC (1.95–3.90 µg ml−1) and MBC (3.90–7.81 µg ml−1) values. The derivatives C-23, C-24 and C-27 have demonstrated good antioxidant potential (IC50 = 7–18 µg ml−1) correlated to the ascorbic acid (IC50 = 4.45 µg ml−1). The derivative C-25 had shown comparable cytotoxicity to camptothecin against A549 cell line. The docking studies predicted the bacterial dihydrofolate reductase (PDB ID: 3SRW) and bacterial DNA gyrase (PDB ID: 4ZVI) as the possible targets for most of the active antimicrobial compounds. These derivatives affirmed their safety by presenting less cytotoxicity towards HEK cells. Further the ADME prediction by qikprop module of the Schrodinger proved that these compounds exhibited drug-like attributes. Hence, these compounds have shown their potential as lead for future expansion of novel antimicrobial and cytotoxic drugs.

  • Dynamic changes of secondary metabolites and tyrosinase activity of Malus pumila flowers
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Lili Cui; Xingzi Hou; Wenjing Li; Yuchun Leng; Yang Zhang; Xinjuan Li; Yangyang Hou; Zhenhua Liu; Wenyi Kang

    The dynamic changes of secondary metabolites and tyrosinase activity of Malus pumila flowers were investigated during blooming for full use of M. pumila flowers. Phlorizin, astragalin and afzelin were selected as the indicators to determine the optimum extraction conditions of M. pumila flowers by HPLC analysis and three-factor and three-level orthogonal design experiments. When the smashing mesh number was 40 mesh, the ultrasonic time was 30 min, the solid–liquid ratio was 1:120, and the centrifugal speed was 10,000 r/min, the total content of the three compounds was the highest. The total content of phlorizin, astragalin and afzelin increased firstly and then decreased, and the highest was on the third day (176.74 mg/g). At the same time, the tyrosinase activity of M. pumila flowers showed that it had an activation effect on tyrosinase during early blooming period, however it exhibited inhibitory effect during late blooming period.

  • Novel LC–MS/MS method for analysis of metformin and canagliflozin in human plasma: application to a pharmacokinetic study
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Dalia Mohamed; Mona S. Elshahed; Tamer Nasr; Nageh Aboutaleb; Ola Zakaria

    Highly sensitive and selective liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous estimation of the recently approved oral hypoglycemic mixture; metformin (MET) and canagliflozin (CFZ) in human plasma using propranolol HCl (PPL) and tadalafil (TDF) as internal standards (IS), respectively. Analytes were extracted using protein precipitation induced by acetonitrile then liquid–liquid extraction was performed using ethyl acetate. Reversed phase HPLC was carried out using C18 analytical column (50 mm × 4.6 mm i.d., 5 µm) with a simple isocratic mobile phase composed of 0.1% formic acid and acetonitrile (60:40, v/v). Detection was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM), with the transitions of m/z 130.2 → 60.1, m/z 462.3 → 191.0, m/z 260.2 → 183.0 and m/z 390.2 → 268.2 for MET, CFZ, PPL and TDF, respectively, in the positive ion mode. The analysis was carried out within 5 min over a linear concentration range of 50–5000 ng/mL for MET and 10–1000 ng/mL for CFZ. The method was validated in accordance with the FDA guidelines for bioanalytical method. All obtained recoveries were higher than 90.0% while the accuracy was in the range of 88.14–113.05% and the relative standard deviation was below 10.0% for all investigated drugs by the proposed method. The achieved promising results has allowed for the successful application of the developed LC–MS/MS method to a pharmacokinetic study of the target drugs after their oral administration to Egyptian healthy volunteers. The pharmacokinetic study was accomplished after the agreement of the ethics committee.

  • A UPLC/DAD method for simultaneous determination of empagliflozin and three related substances in spiked human plasma
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Mokhtar M. Mabrouk; Suzan M. Soliman; Heba M. El-Agizy; Fotouh R. Mansour

    A simple, rapid and sensitive ultrahigh performance liquid chromatographic method was developed for the determination of the anti-diabetic drug: empagliflozin (EMPA) and three related substances in spiked human plasma, using dapagliflozin (DAPA) as an internal standard and tetrahydrofuran as a plasma protein precipitating agent. The chromatographic separation was achieved on an Acquity “UPLC® BEH” C18 column (50 mm × 2.1 mm i.d, 1.7 µm particle size), and a mobile phase consisting of aqueous trifluoroacetic acid (0.1%, pH 2.5): acetonitrile (60:40, v/v) at a flow rate of 0.5 mL/min. Upon using the UPLC system, the run time could be reduced to less than 1.2 min, and the solvents consumption decreased to 0.36 mL of acetonitrile per run. The response was linear over a concentration range of 50–700 ng/mL and 40–200 ng/mL (r2 = 0.9994–0.9999) with lower limits of detection and quantification (LOD/LOQ) of 15/50, 11.5/40, 12/40 and 12.5/40 ng/mL for EMPA and the three related substances, respectively. Good accuracy was obtained with mean percentage recoveries ≥ 96.97% for the studied compounds. The method was validated according to the ICH guidelines and was found suitable for routine analysis of EMPA and its related substances in human plasma.

  • Assessment of lipophilicity of newly synthesized celecoxib analogues using reversed-phase HPLC
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Heba Elmansi; Jenny Jeehan Nasr; Azza H. Rageh; Mohamed I. El-Awady; Ghada S. Hassan; Hatem A. Abdel-Aziz; Fathalla Belal

    Lipophilicity is a physicochemical property of an essential importance in medicinal chemistry; therefore, fast and reliable measurement of lipophilicity will affect greatly the drug discovery process. A series of N-benzenesulfonamide-1H-pyrazoles, oximes and hydrazones as celecoxib analogues was investigated with regard to their retention behavior using reversed-phase high performance liquid chromatography (RP-HPLC). The mobile phases employed for this study consist of a mixture of water and methanol in different proportions. In addition, the stationary phase utilized for this separation was C18 silanized silica gel and using 200 nm as a detection wavelength. The retention behavior of the investigated compounds was determined based on practical determination of log k at different concentrations of methanol (as an organic modifier) in the mobile phase ranging from 60 to 80%. It was observed that the retention of these compounds (expressed as log k) decreased in a linear manner with increasing the concentration of methanol. High correlation coefficients (more than 0.90 in most cases) were obtained for the relationship between the volume fraction of the organic solvent and the retention values represented as log kw. A comparative evaluation was carried out between chromatographically-obtained lipophilicity parameters (represented as lipophilicity chromatographic index log kw or isocratic chromatographic hydrophobicity index, $$\varphi$$ 0) and the computationally calculated log P values (miLogP, ALOGP, ACD/Labs and ALOGPs). It was found that a good correlation exists between the experimental and computed log P values. In the future, these results can give a deep insight about the anti-inflammatory and analgesic activity of the newly synthesized compounds.

  • Molecular docking, synthesis and biological significance of pyrimidine analogues as prospective antimicrobial and antiproliferative agents
    BMC Chem. (IF 2.284) Pub Date : 2019-07-09
    Sanjiv Kumar; Archana Kaushik; Balasubramanian Narasimhan; Syed Adnan Ali Shah; Siong Meng Lim; Kalavathy Ramasamy; Vasudevan Mani

    Pyrimidine nucleus is a significant pharmacophore that exhibited excellent pharmacological activities. A series of pyrimidine scaffolds was synthesized and its chemical structures were confirmed by physicochemical and spectral analysis. The synthesized compounds were evaluated for their antimicrobial potential towards Gram positive and negative bacteria as well as fungal species. They were also assessed for their anticancer activity toward a human colorectal carcinoma cell line (HCT116). Whilst results of antimicrobial potential revealed that compounds Ax2, Ax3, Ax8 and Ax14 exhibited better activity against tested microorganisms, the results of antiproliferative activity indicated that compounds Ax7 and Ax10 showed excellent activity against HCT116. Further, the molecular docking of pyrimidine derivatives Ax1, Ax9 and Ax10 with CDK8 (PDB id: 5FGK) protein indicated that moderate to better docking results within the binding pocket. Compounds Ax8 and Ax10 having significant antimicrobial and anticancer activities may be selected as lead compounds for the development of novel antimicrobial and anticancer agent, respectively.

  • Electrodeposition of amorphous molybdenum sulfide thin film for electrochemical hydrogen evolution reaction
    BMC Chem. (IF 2.284) Pub Date : 2019-07-10
    Lina Zhang; Liangliu Wu; Jing Li; Jinglei Lei

    Amorphous molybdenum sulfide (MoSx) is a highly active noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER). The MoSx was prepared by electrochemical deposition at room temperature. Low-cost precursors of Mo and S were adopted to synthesize thiomolybdates solution as the electrolyte. It replaces the expensive (NH)2MoS4 and avoid the poison gas (H2S) to generate or employ. The (MoO2S2)2−, (MoOS3)2− and (MoS4)2− ions were determined by UV–VIS spectroscopy. The electrodeposition of MoSx was confirmed with XRD, XPS and SEM. The electrocatalyst activity was measured by polarization curve. The electrolyte contained (MoO2S2)2− ion and (MoOS3)2− ion electrodeposit the MoSx thin film displays a relatively high activity for HER with low overpotential of 211 mV at a current density of 10 mA cm−2, a relatively high current density of 21.03 mA cm−2 at η = 250 mV, a small Tafel slope of 55 mV dec−1. The added sodium dodecyl sulfate (SDS) can efficient improve the stability of the MoSx film catalyst.

  • A minireview of hydroamination catalysis: alkene and alkyne substrate selective, metal complex design
    BMC Chem. (IF 2.284) Pub Date : 2019-07-11
    Jingpei Huo; Guozhang He; Weilan Chen; Xiaohong Hu; Qianjun Deng; Dongchu Chen

    Organic compounds that contain nitrogen are very important intermediates in pharmaceutical and chemical industry. Hydroamination is the reaction that can form C–N bond with high atom economy. The research progress in metals catalyzed hydroamination of alkenes and alkynes from the perspective of reaction mechanism is categorized and summarized.

  • In-silico molecular design of heterocyclic benzimidazole scaffolds as prospective anticancer agents
    BMC Chem. (IF 2.284) Pub Date : 2019-07-11
    Sumit Tahlan; Sanjiv Kumar; Kalavathy Ramasamy; Siong Meng Lim; Syed Adnan Ali Shah; Vasudevan Mani; Balasubramanian Narasimhan

    Benzimidazole is a valuable pharmacophore in the field of medicinal chemistry and exhibit wide spectrum of biological activity. Molecular docking technique is routinely used in modern drug discovery for understanding the drug-receptor interaction. The selected data set of synthesized benzimidazole compounds was evaluated for its in vitro anticancer activity against cancer cell lines (HCT116 and MCF7) by sulforhodamine B (SRB) assay. Further, molecular docking study of data set was carried out by Schrodinger-Maestro v11.5 using CDK-8 (PDB code: 5FGK) and ER-alpha (PDB code: 3ERT) as possible target for anticancer activity. Molecular docking results demonstrated that compounds 12, 16, N9, W20 and Z24 displayed good docking score with better interaction within crucial amino acids and corelate to their anticancer results. ADME results indicated that compounds 16, N9 and W20 have significant results within the close agreement of the Lipinski’s rule of five and Qikprop rule within the range and these compounds may be taken as lead molecules for the discovery of new anticancer agents.

  • Design, synthesis, and biological evaluation of novel N4-substituted sulfonamides: acetamides derivatives as dihydrofolate reductase (DHFR) inhibitors
    BMC Chem. (IF 2.284) Pub Date : 2019-07-11
    Essam M. Hussein; Munirah M. Al-Rooqi; Shimaa M. Abd El-Galil; Saleh A. Ahmed

    Sulfonamide derivatives are of great attention due to their wide spectrum of biological activities. Sulfonamides conjugated with acetamide fragments exhibit antimicrobial and anticancer activities. The inhibition dihydrofolate reductase (DHFR) is considered as one of the most prominent mechanism though which sulfonamide derivatives exhibits antimicrobial and antitumor activities. In this study, a new series of 2-(arylamino)acetamides and N-arylacetamides containing sulfonamide moieties were designed, synthesized, characterized and assessed for their antimicrobial activity and screened for cytotoxic activity against human lung carcinoma (A-549) and human breast carcinoma (MCF-7) cell lines. A molecular docking study was performed to identify the mode of action of the synthesized compounds and their good binding interactions were observed with the active sites of dihydrofolate reductase (DHFR). Most of the synthesized compounds showed significant activity against A-549 and MCF-7 when compared to 5-Fluorouracil (5-FU), which was used as a reference drug. Some of these synthesized compounds are active as antibacterial and antifungal agents.

  • Oligosaccharide-based quality evaluation of Atractylodis rhizome and a strategy for simplifying its quality control
    BMC Chem. (IF 2.284) Pub Date : 2019-07-12
    Dan Zhuang; Jing Qin; Hui-yang Wang; Yi Zhang; Chun-yao Liu; Qing-qing Ding; Guang-ping Lv

    Atractylodis rhizoma, is the dried rhizomes of Atractylodes lancea (Thunb.) DC. or A. chinensis (DC.) Koidz. Both of two are pharmacologically and economically important, while with differences in efficacy. Therefore, an authentication system is vital for evaluation the quality and discrimination adulteration of Atractylodis rhizoma. Fructooligosaccharides (FOS), which are regarded as functional ingredients in Atractylodis rhizoma, have not been used for quality control of Atractylodis rhizoma for shortage of reference compounds. A HPLC-ELSD method was developed for the quantification of FOS in Atractylodis rhizoma. And chemometrics analysis showed that 2 markers including content of degree of polymerization (DP) 12 and total content of DP 3-15 could be used as the main distinctive elements for quality evaluation of Atractylodis rhizome. Actually, the separation and purification of high DP FOS, such as DP 12, is still a challenge because of high polarity. Then DP 5-based qualification evaluation was investigated for quality control of Atractylodis rhizoma. The results showed that A. lancea and A. chinensis could be clearly separated. DP 5-based quantification method was credible and effectively adopted for solving the shortage of reference compounds and improving the quality control of Atractylodis rhizoma

  • Analysis of chemical constituents in mainstream bidi smoke
    BMC Chem. (IF 2.284) Pub Date : 2019-07-22
    Omobola Ajoke Oladipupo; Dibyendu Dutta; Ngee Sing Chong

    Bidi, an indigenous form of cigarette in South Asian countries, is popular because of its low cost and multi-flavored variants. Although recent studies have shown that bidi smokers suffer from various adverse health effects including cancer, research on bidi smoke composition and exposure levels is still very limited. In this research, the vapor and particulate phases of bidi were characterized using gas chromatography coupled with mass spectrometry (GC–MS) and Fourier-transform infrared spectrometry (FTIR). The amounts of nicotine, cotinine, indole, substituted phenols, substituted pyridines, and phytol found in different size fractions of the particulate matter collected using a cascade impactor were reported. Due to the low combustibility of the tendu leaf in bidi, a six-second puff interval was used to sample the smoke constituents for analysis. Significant levels of carbon monoxide, hydrogen cyanide, and hydrocarbons like ethylene, methane and 1, 3-butadiene were detected in the mainstream bidi smoke. In addition, 3-methylpyridine, cotinine, α-amyrin, and β-amyrin were also present at high levels in bidi smoke. Despite having less tobacco compared to conventional cigarette, bidi smokers are potentially exposed to significantly higher concentrations of nicotine due to the greater puffing frequency. The non-porous nature and higher moisture content of tendu leaf in bidis compared to cigarette wrapping paper led to higher levels of carbon monoxide and tar in bidi smoke compared to regular cigarette smoke. Results of this study indicate the presence of harmful and carcinogenic chemicals in the mainstream bidi smoke that could be harmful to human health.

  • Binding interaction of sodium benzoate food additive with bovine serum albumin: multi-spectroscopy and molecular docking studies
    BMC Chem. (IF 2.284) Pub Date : 2019-07-24
    Jing Yu; Jian-Yi Liu; Wei-Ming Xiong; Xiao-Yue Zhang; Yue Zheng

    Sodium benzoate (SB) is widely used as a preservative in food industry, and bovine serum albumin (BSA) is a major carrier protein similar to human serum albumin (HSA), the study of the binding between the two has great significance on human health. In this paper, we systematically investigated the binding of SB and BSA under the simulated physiological conditions combining with various common analytical methods, e.g., fluorescence, UV–vis absorption, synchronous fluorescence and circular dichroism (CD) spectra, as well as molecular docking method. The fluorescence quenching measurements were respectively carried out at 298 K, 303 K and 308 K using the Stern–Volmer method. The results reveal that ground state SB–BSA complex was formed within the binding constants from 2.02 × 104 to 7.9 × 103 M−1. Meanwhile, the negative values of ΔH0 (− 43.92 kJ mol−1) and ΔS0 (− 111.6 J mol−1 K−1) demonstrated that both the hydrogen binding interaction and van der Waals forces contributed to stabilizing the SB–BSA complex. The site marker competitive experiments show that the SB and BSA bound at site I. Furthermore, the experimental results of UV–vis absorption, synchronous fluorescence and CD spectra indicate that the binding of SB and BSA may change the conformation of BSA. In addition, the molecular docking experiment suggests that hydrogen bond was formed in the interaction between SB and BSA.

  • Identification of C-glycosyl flavones by high performance liquid chromatography electrospray ionization mass spectrometry and quantification of five main C-glycosyl flavones in Flickingeria fimbriata
    BMC Chem. (IF 2.284) Pub Date : 2019-07-23
    Yawen Wang; Zhiyun Liang; Xian Liao; Chujuan Zhou; Zhenshan Xie; Sha Zhu; Gang Wei; Yuechun Huang

    Flickingeria fimbriata is commonly applied in China as a traditional Chinese medicine (TCM), however the quality control of it is incomplete. In this work, we aim to identify and quantify the structures of C-glycosyl flavones in F. fimbriata. High performance liquid chromatography-diode array detector (HPLC-DAD) and High performance liquid chromatography–electrospray ionization–multiple stage tandem mass spectrometry (HPLC–ESI–MSn) methods were combined to identify C-glycosyl flavones and determine their contents. Twenty acylated C-glycosyl flavones and ten non-acylated C-glycosyl flavones were identified for the first time in F. fimbriata on systematic MSn analysis via HPLC–ESI–MSn. The aglycones of all of these compounds were apigenin or chrysoeriol and were acylated with p-coumaric, ferulic, 3,4-dimethoxycinnamic or 3,4,5-trimethoxycinnamic acids. Furthermore, the quantification result suggest that two C-glycosyl flavones (vicenin-I and vicenin-III) with relative high contents were revealed to be more strongly acylated in F. fimbriata. The method is sufficiently precise, accurate, and sensitive for the qualitative and quantitative analysis of C-glycosyl flavones, which is expected to establish a standard for quality control and identification in this plant.

  • Computational approaches: discovery of GTPase HRas as prospective drug target for 1,3-diazine scaffolds
    BMC Chem. (IF 2.284) Pub Date : 2019-07-24
    Sanjiv Kumar; Deepika Sharma; Balasubramanian Narasimhan; Kalavathy Ramasamy; Syed Adnan Ali Shah; Siong Meng Lim; Vasudevan Mani

    Heterocyclic 1,3-diazine nucleus is a valuable pharmacophore in the field of medicinal chemistry and exhibit a wide spectrum of biological activities. PharmMapper, a robust online tool used for establishing the target proteins based on reverse pharmacophore mapping. PharmMapper study is carried out to explore the pharmacological activity of 1,3-diazine derivatives using reverse docking program. PharmMapper, an open web server was used to recognize for all the feasible target proteins for the developed compounds through reverse pharmacophore mapping. The results were analyzed via molecular docking with maestro v11.5 (Schrodinger 2018-1) using GTPase HRas as possible target. The molecular docking studies displayed the binding behavior of 1,3-diazine within GTP binding pocket. From the docking study compounds s3 and s14 showed better docked score with anticancer potency against cancer cell line (HCT116). Hence, the GTPase HRas may be the possible target of 1,3-diazine derivatives for their anticancer activity where the retrieved information may be quite useful for developing rational drug designing. Furthermore the selected 1,3-diazine compounds were evaluated for their in vitro anticancer activity against murine macrophages cell line. 1,3-Diazine compounds exhibited good selectivity of the compounds towards the human colorectal carcinoma cell line instead of the murine macrophages. The toxicity study of the most active compounds was also performed on non cancerous HEK-293 cell line.

  • Peanut shell as a green biomolecule support for anchoring Cu2O: a biocatalyst for green synthesis of 1,2,3-triazoles under ultrasonic irradiation
    BMC Chem. (IF 2.284) Pub Date : 2019-07-24
    Zahra Dolatkhah; Abolfazl Mohammadkhani; Shahrzad Javanshir; Ayoob Bazgir

    Cu2O supported on peanut shell (Cu2O@PS) was prepared by the reaction of copper acetate and peanut shell powder as a naturally available biopolymer support. The prepared catalyst was used as an efficient and reusable heterogeneous catalyst in the click reaction of benzyl halide or phenacyl bromides, acetylenes and sodium azide for the synthesis of potentially biologically active 1,2,3-triazoles under ultrasonic irradiation in EtOH-H2O as green solvent.

  • Sulfonic acid-functionalized polyallylamine (sevelamer) as an efficient reusable strong solid acid catalyst for the synthesis of xanthenes derivatives
    BMC Chem. (IF 2.284) Pub Date : 2019-07-26
    Xian-Liang Zhao; Makombe Shelton; Ke-Fang Yang

    Sevelamer (polyallyamine resin)-supported sulfonic acid (S-SO3H) has been prepared from the reaction of sevelamer with chlorosulfonic acid and characterized using FT-IR spectroscopy, scanning electronmicroscopy (SEM) and thermogravimetric analysis (TGA). The catalytic activity of S-SO3H was investigated in the synthesis of 1,8-dioxo-octahydroxanthene derivatives. All of the reactions were fast and gave excellent yields. The catalyst was easily recovered and reused for 5 runs without significant loss of its catalytic activity.

  • Potentiometric sensor for iron (III) quantitative determination: experimental and computational approaches
    BMC Chem. (IF 2.284) Pub Date : 2019-11-18
    Somayeh Badakhshan; Saeid Ahmadzadeh; Anoushiravan Mohseni-Bandpei; Majid Aghasi; Amir Basiri

    The current work deals with fabrication and validation of a new highly Fe3+ selective sensor based on benzo-18-crown-6 (b-18C6) using the potentiometric method. The proposed sensor revealed satisfactory performance for quantitative evaluation of Fe3+ trace amount in environmental samples. The ratio of membrane ingredients optimized and the membrane with the composition of 4:30:65.5:0.5 mg of b-18C6:PVC:o-NPOE:KTpClPB exhibited the desirable Nernstian slope of 19.51 ± 0.10 (mV per decade of activity) over the pH range from 2.5 to 5.7 with an acceptable dynamic concentration range of 1.0 × 10−6 M to 1.0 × 10−1 M and lower detection limit of 8.0 × 10−7 M. The proposed sensor demonstrated an appropriate reproducibility with a rapid response time of 12 s and the suitable lifetime of 10 weeks. To validate the accurate response of the proposed sensor, AAS technique applied for the determination of Fe3+ in real aqueous mediums such as drinking tap water and hospital wastewater sample after treatment by electrocoagulation process. Theoretical studies carried out using DFT/B3LYP computational level with 6-311G basis set to optimize the adsorption sites of Fe+3 cationic species by b-18C6. The obtained adsorption energy with large negative value confirmed the formation of a stable complex.

  • Preparation of sub-microspherical Fe3O4@PDA-Pd NPs catalyst and application in catalytic hydroreduction reaction of halogenated aromatic nitro compounds to prepare halogenated aromatic amines
    BMC Chem. (IF 2.284) Pub Date : 2019-11-13
    Haichang Guo; Renhua Zheng; Huajiang Jiang; Zhenyuan Xu; Aibao Xia

    The side reactions of dehalogenation or C–N coupling tend to occur when halogenated aromatic amines are prepared by catalytic hydrogenation reduction of halogenated aromatic nitro compounds. In this paper, we prepared the sub-microspherical Fe3O4@PDA-Pd NPs catalyst apply it efficiently in the hydrogenation reduction of halogenated aromatic nitro compounds to prepare the halogenated aromatic amines under atmospheric pressure. The catalyst shows a high selectivity of greater than 96% and can effectively inhibit the occurrence of the side reactions of dehalogenation and C–N coupling. The optimum condition of the hydroreduction reaction is when tetrahydrofuran is used as solvent and the reaction happens at 50 °C for 5 h. The selectivity of the chlorinated aromatic amine and the fluorinated aromatic amine products exceed 99% and the yield exceeds 90%. Only a small amount of dehalogenated products and C–N coupling by-products were produced in the brominated aromatic compound and the iodinated aromatic compound. We developed a promising method for preparing the superparamagnetic and strongly magnetic Fe3O4@PDA core–shell sub-microsphere-supported nano-palladium catalyst for catalyzing the hydrogenation reduction of halogenated aromatic nitro compounds. The halogenated aromatic amines were efficiently and highly selectively prepared under atmospheric pressure, with the side reactions of dehalogenation and C–N coupling effectively inhabited simultaneously.

  • Mechanistic formation of hazardous molecular heterocyclic amines from high temperature pyrolysis of model biomass materials: cellulose and tyrosine
    BMC Chem. (IF 2.284) Pub Date : 2019-11-08
    Samuel K. Kirkok; Joshua K. Kibet; Francis Okanga; Thomas Kinyanjui; Vincent Nyamori

    Research inventories on the co-pyrolysis of major biomass components such as cellulose with amino acid materials is scarce in literature despite the fact that such studies are critical in understanding toxic product relations from high temperature cooking, combustion of bio-fuels, cigarette smoking and forest fires. This paper explores, quantitatively, the yields of heterocyclic nitrogenated molecular reaction products of grave mutagenetic concern from the co-pyrolysis of model biomass materials; tyrosine and cellulose. Research has established that heterocyclic amines such as isocyanates are mutagens as well precursors for asthma, and other respiratory disorders. An equimassic mixture of tyrosine and cellulose (50 ± 2 mg) by weight were pyrolyzed in a tubular quartz reactor in flowing nitrogen at 1 atm. Besides, varying combinations of tyrosine and cellulose in the ratios 3:1 and 1:3 were also explored for comparison. The reaction time was set at 2 s so as to simulate combustions events in nature. The pyrolysate was collected over 5 mL dichloromethane and characterized using a gas chromatograph coupled to a mass spectrometer detector. Evidently, it was noted that 1-methylindazole was released in high yields at 300 °C, constituting ~ 300 µg in the entire pyrolysis temperature range (200–700 °C). Nonetheless, isoindazole gave the highest yield ~ 730 µg while 1-naphthyl isocyanate gave a total yield of ~ 336 µg in the same temperature range. Remarkably, the change in char yield between 300 and 450 °C for the pyrolysis of 25% tyrosine in 75% cellulose was found to be ~ 48% whereas the change in char yield for the pyrolysis of 75% tyrosine in 25% cellulose was 49%. The char and tar yields considered important residues of biomass burning have been reported in this study and found to be consistent with other research output in literature. The striking similarities of % yield of char across all temperatures for various combinations was the most significant observation in this investigation—char yield was independent of the mixing ratio during pyrolysis. From a mechanistic standpoint, it was noted that tyrosine inhibited cellulose based nitrogenated products. Thus N-products dominated the O-products.

  • Benzimidazole Schiff base derivatives: synthesis, characterization and antimicrobial activity
    BMC Chem. (IF 2.284) Pub Date : 2019-11-09
    Thierry Youmbi Fonkui; Monisola Itohan Ikhile; Patrick Berka Njobeh; Derek Tantoh Ndinteh

    A series of Schiff bases (3.a–f) bearing benzimidazole moiety was successfully synthesized in ethanol by refluxing Oct-2-ynoic acid (1,3-dihydrobenzimidazole-2-ylidene)amide with substituted amines. Fourier transform infrared (FTIR), ultra violet light (UV–VIS), elemental analysis, proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy were used to characterize the newly synthesized Schiff bases. Micro dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the Schiff bases, against 14 human pathogenic bacteria (8 Gram negative and 6 Gram positive) and against 7 fungal strains (5 Aspergillus and 2 Fusarium) representatives. Antimalarial activity against Plasmodium falciparum and antitrypanosomal property against Trypanosoma brucei was studied in vitro at a single dose concentration of the Schiff bases. Cytotoxicity of the Schiff bases was assessed against human cervix adenocarcinoma (HeLa) cells. Results obtained show that the newly synthesized Schiff bases are very potent antimicrobial agents. Gram negative bacteria Klebsiella pneumonia and Escherichia coli were more affected on exposure to Compounds 3.c–f (MIC 7.8 µg/mL) which in turn exhibited more antibacterial potency than nalidixic acid reference drug that displayed MICs between 64 and 512 µg/mL against K. pneumonia and E. coli respectively. The test compounds also demonstrated high cytotoxic effect against Aspergillus flavus and Aspergillus carbonarius as they displayed MFC 7.8 and 15.6 µg/mL. Compound 3.c exhibited the highest fungicidal property from this series with MFC alternating between 7.8 and 15.6 µg/mL against the investigated strains. The malarial activity revealed Compounds 3.c and 3.d as the more potent antiplasmodial compounds in this group exhibiting 95% and 85% growth inhibition respectively. The IC50 of Compounds 3.c and 3.d were determined and found to be IC50 26.96 and 28.31 µg/mL respectively. Compound 3.a was the most cytotoxic agent against HeLa cells in this group with 48% cell growth inhibition. Compounds 3.c, 3.d and 3.f were biocompatible with HeLa cells and displayed low toxicity. With a very low cytotoxic effect against HeLa, compound 3.c stands out to be a very good antiparasitic agent and consideration to further evaluate the candidate drug against others cell lines is necessary.

  • Study of the mechanism of change in flavonoid composition in the processing of Chrysanthemum morifolium (Ramat.) Tzvel. ‘Boju’
    BMC Chem. (IF 2.284) Pub Date : 2019-11-09
    Wei Zhang; Yafeng Zuo; Fengqing Xu; Tongsheng Wang; Jinsong Liu; Deling Wu

    A form of β-glucosidase was isolated and purified from fresh Chrysanthemum morifolium (Ramat.) Tzvel. ‘Boju’ (Boju) and its enzymatic properties explored in this study. The purified enzyme and Boju flavonoids were reacted in a water bath to ascertain the composition of the reactants. Flavonoid glycoside and aglycon concentrations in Boju varied significantly depending on processing method. The concentration of flavonoid glycosides in Boju decreased and flavonoid aglycons increased due to heat-activation of β-glucosidase which hydrolyzed the flavonoid glycosides in Boju to aglycons.

  • A novel electrochemical aptasensor for fumonisin B1 determination using DNA and exonuclease-I as signal amplification strategy
    BMC Chem. (IF 2.284) Pub Date : 2019-11-09
    Min Wei; Fei Zhao; Shuo Feng; Huali Jin

    In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3′ end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3′–5′ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0 × 10−3–1000 ng mL−1 with a low limit of detection of 0.15 pg mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

  • A green and facile synthesis of an industrially important quaternary heterocyclic intermediates for baricitinib
    BMC Chem. (IF 2.284) Pub Date : 2019-10-31
    Xin Cui; Junming Du; Zongqing Jia; Xilong Wang; Haiyong Jia

    Baricitinib, with a 2-(1-(ethylsulfonyl)azetidin-3-yl)acetonitrile moiety at N-2 position of the pyrazol skeleton, is an oral and selective reversible inhibitor of the JAK1 and JAK2 and displays potent anti-inflammatory activity. Several research-scale synthetic methods have been reported for the preparation of key quaternary heterocyclic intermediates of baricitinib. However, they were all associated with several drawbacks, such as the expensive materials, usage of pollutional reagents, and poor yields. In this manuscript, we established a green and cost-effective synthesis of 2-(1-(ethylsulfonyl)azetidin-3-ylidene)acetonitrile and tert-butyl 3-(cyanomethylene)azetidine-1-carboxylate for further scale-up production of baricitinib. This synthetic method employs commercially available and low-cost starting material benzylamine and an industry-oriented reaction of green oxidation reaction in microchannel reactor to yield important quaternary heterocyclic intermediates. Generally, this procedure is reasonable, green and suitable for industrial production.

  • gem-Difluorobisarylic derivatives: design, synthesis and anti-inflammatory effect
    BMC Chem. (IF 2.284) Pub Date : 2019-10-31
    Abeer J. Ayoub; Layal Hariss; Nehme El-Hachem; Ghewa A. El-Achkar; Sandra E. Ghayad; Oula K. Dagher; Nada Borghol; René Grée; Bassam Badran; Ali Hachem; Eva Hamade; Aida Habib

    New fluorinated diaryl ethers and bisarylic ketones were designed and evaluated for their anti-inflammatory effects in primary macrophages. The synthesis of the designed molecules started from easily accessible and versatile gem-difluoro propargylic derivatives. The desired aromatic systems were obtained using Diels–Alder/aromatization sequences and this was followed by Pd-catalyzed coupling reactions and, when required, final functionalization steps. Both direct inhibitory effects on cyclooxygenase-1 or -2 activities, protein expression of cyclooxygenase-2 and nitric oxide synthase-II and the production of prostaglandin E2, the pro-inflammatory nitric oxide and interleukin-6 were evaluated in primary murine bone marrow-derived macrophages in response to lipopolysaccharide. Docking of the designed molecules in cyclooxygenase-1 or -2 was performed. Only fluorinated compounds exerted anti-inflammatory activities by lowering the secretion of interleukin-6, nitric oxide, and prostaglandin E2, and decreasing the protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in mouse primary macrophages exposed to lipopolysaccharide, as well as cyclooxygenase activity for some inhibitors with different efficiencies depending on the R-groups. Docking observation suggested an inhibitory role of cyclooxygenase-1 or -2 for compounds A3, A4 and A5 in addition to their capacity to inhibit nitrite, interleukin-6, and nitric oxide synthase-II and cyclooxygenase-2 expression. The new fluorinated diaryl ethers and bisarylic ketones have anti-inflammatory effects in macrophages. These fluorinated compounds have improved potential anti-inflammatory properties due to the fluorine residues in the bioactive molecules.

  • Direct analysis of volatile components from intact jujube by carbon fiber ionization mass spectrometry
    BMC Chem. (IF 2.284) Pub Date : 2019-10-31
    Shihao Sun; Yihan Zhang; Peng Li; Hui Xi; Lei Wu; Jianxun Zhang; Guixin Peng; Yue Su

    In situ analysis of odor is an important approach to connect odor with chemical composition. However, it is difficult to conduct a rapid direct analysis of the odor sample because of low analyte concentration and sampling. To achieve the direct analysis, a carbon fiber ionization mass spectrometry (CFI-MS) method has been developed and applied to measure volatile components releasing from intact jujube. To build the CFI source, a 2.0-cm long carbon fiber bundle was integrated on the pin of a commercial corona discharge needle by mean of a 1.3-cm long stainless hollow tube. Odor sample driven by N2 gas can be directly introduced to the carbon fiber bundle to complete the ionization of analytes. Acetic acid, ethyl acetate, ethyl caproate, octyl acetate, and damascone present in jujube were selected to evaluate the performance of the CFI-MS method on quantitative analysis of the gaseous sample. Good lineary was obtained (R2 ≥ 0.9946) between 5.0 and 500.0 ng/L with limits of detection (LOD) ranging from 0.5 to 1.5 ng/L. Recoveries of five volatile compounds for the spiked jujube samples were between 94.36 and 106.74% with relative standard deviations (RSDs) less than 7.27% (n = 5). Jujube of different varieties can be distinguished by principal components analysis based on the analytical results of volatile compounds. The developed method demonstrated obvious advantages such as simplicity, high throughput, good sensitivity and wide range of applicability, which will be an alternative way for in situ analysis of the odor sample.

  • Biorenewable triblock copolymers consisting of l-lactide and ε-caprolactone for removing organic pollutants from water: a lifecycle neutral solution
    BMC Chem. (IF 2.284) Pub Date : 2019-10-22
    Katrina T. Bernhardt; Haley G. Collins; Amy M. Balija

    Current methods of removing organic pollutants from water are becoming ineffective as the world population increases. In this study, a series of biorenewable triblock copolymers with hydrophobic poly(ε-caprolactone) block and hydrophilic poly(l-lactide) blocks were synthesized and tested as agents to remove environmental pollutants from an aqueous solution. The percent of pollutant removed and equilibrium inclusion constants were calculated for the polymers. These values were compared to previously known removal agents for their effectiveness. Triblock copolymer samples removed over 70% of the polycyclic aromatic hydrocarbon (PAH) phenanthrene from an aqueous solution, with selectivity for the adsorption of phenanthrene over other PAHs tested. The inclusion constant was 7.4 × 105 M−1 and adsorption capacity was 5.8 × 10−7 mol phenanthrene/g polymer. Rose Bengal was used to further probe the nature of interactions between the copolymers and a small molecule guest. Solid samples of the block-poly(l-lactide)–block-poly(ε-caprolactone)–block-poly(l-lactide) (PLLA–PCL–PLLA) systems were found to rapidly remove over 90% of Rose Bengal from aqueous solution, resulting in a complete disappearance of the characteristic pink color. Solutions of the copolymers in dichloromethane also removed Rose Bengal from water with a similar level of efficiency. Large inclusion constant values were obtained, ranging from 1.0 × 105 to 7.9 × 105 M−1, and the average adsorption capacity value of 6.2 × 10−7 mol/g polymer was determined. Aged polymer samples exhibited different adsorption characteristics and mechanistic theories for the removal of Rose Bengal were determined. The triblock copolymer consisting of l-lactide and ε-caprolactone was effective in removing various organic pollutants in aqueous environments. It is a biorenewable material which leads to minimal waste production during its lifecycle. These polymers were in general more effective in removing organic pollutants than commercially available pollution removal systems.

  • Graphene-based biosensors for the detection of prostate cancer protein biomarkers: a review
    BMC Chem. (IF 2.284) Pub Date : 2019-09-03
    Li Xu; Yanli Wen; Santosh Pandit; Venkata R. S. S. Mokkapati; Ivan Mijakovic; Yan Li; Min Ding; Shuzhen Ren; Wen Li; Gang Liu

    Prostate cancer (PC) is the sixth most common cancer type in the world, which causes approximately 10% of total cancer fatalities. The detection of protein biomarkers in body fluids is the key topic for the diagnosis and prognosis of PC. Highly sensitive screening of PC is the most effective approach for reducing mortality. Thus, there are a growing number of literature that recognizes the importance of new technologies for early diagnosis of PC. Graphene is playing an important role in the biosensor field with remarkable physical, optical, electrochemical and magnetic properties. Many recent studies demonstrated the potential of graphene materials for sensitive detection of protein biomarkers. In this review, the graphene-based biosensors toward PC analysis are mainly discussed in two groups: Firstly, novel biosensor interfaces were constructed through the modification of graphene materials onto sensor surfaces. Secondly, ingenious signal amplification strategies were developed using graphene materials as catalysts or carriers. Graphene-based biosensors have exhibited remarkable performance with high sensitivities, wide detection ranges, and long-term stabilities.

  • Synthesis, molecular docking and biological potentials of new 2-(4-(2-chloroacetyl) piperazin-1-yl)-N-(2-(4-chlorophenyl)-4-oxoquinazolin-3(4H)-yl)acetamide derivatives
    BMC Chem. (IF 2.284) Pub Date : 2019-09-05
    Shinky Mehta; Sanjiv Kumar; Rakesh Kumar Marwaha; Balasubramanian Narasimhan; Kalavathy Ramasamy; Siong Meng Lim; Syed Adnan Ali Shah; Vasudevan Mani

    In the present study, a series of 2-(4-(2-chloroacetyl)piperazin-1-yl)-N-(2-(4-chlorophenyl)-4-oxoquinazolin-3(4H)-yl)acetamide derivatives was synthesized and its chemical structures were confirmed by physicochemical and spectral characteristics. The synthesized compounds were evaluated for their in vitro antimicrobial (tube dilution technique) and anticancer (MTT assay) activities along with molecular docking study by Schrodinger 2018-1, maestro v11.5. The antimicrobial results indicated that compounds 3, 8, 11 and 12 displayed the significant antimicrobial activity and comparable to the standards drugs (ciprofloxacin and fluconazole). The anticancer activity results indicated that compound 5 have good anticancer activity among the synthesized compounds but lower active than the standard drugs (5-fluorouracil and tomudex). Molecular docking study demonstrated that compounds 5 and 7 displayed the good docking score with better anticancer potency within the binding pocket and these compounds may be used as a lead for rational drug designing for the anticancer molecules.

  • Chemical modification of Bombyx mori silk fibers with vinyl groups for thiol-ene click chemistry
    BMC Chem. (IF 2.284) Pub Date : 2019-09-10
    Xiaoning Zhang; Jianwei Liang; Zhenyu Chen; Carrie Donley; Yuling Liu; Guotao Cheng

    Natural Bombyx mori silk fibroin (SF) fibers were modified with 2-methacryloyloxyethyl isocyanate (MOI) first for the introduction of vinyl groups. Then, 1H,1H,2H,2H-perfluorodecanethiol was grafted onto the SF fibers via thiol-ene click chemistry using ultraviolet light. The formations of MOI-modified and PFDT-grafted SF fibers were analyzed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The morphology of samples was also revealed by a scanning electron microscope. In addition, differential scanning calorimetry results demonstrated that SF fibers did not show significant change in thermal behavior, regardless of the chemical modification. To confirm the cytotoxicity of the prepared SF fibers, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed, and no toxicity was observed with PFDT-grafted SF fibers. The results also showed that PFDT-grafted SF fibers exhibited good antifouling properties when Chlorella vulgaris (C. vulgaris) was selected as a model for algal cells adhesion experiment.

  • Designing, synthesis and characterization of 2-aminothiazole-4-carboxylate Schiff bases; antimicrobial evaluation against multidrug resistant strains and molecular docking
    BMC Chem. (IF 2.284) Pub Date : 2019-09-14
    Saima Ejaz; Humaira Nadeem; Rehan Zafar Paracha; Sadia Sarwar; Sadaf Ejaz

    2-Aminothiazoles are significant class of organic medicinal compounds utilized as starting material for the synthesis of diverse range of heterocyclic analogues with promising therapeutic roles as antibacterial, antifungal, anti-HIV, antioxidant, antitumor, anthelmintic, anti-inflammatory & analgesic agents. Eight compounds 1a, 2a–2g were synthesized and characterized by FTIR and NMR (1H and 13C). Evaluation of antibacterial potential against multi-drug resistant clinical isolates was performed and minimum inhibitory concentration (MIC) values were determined. Antifungal activity was also performed. Protein–ligand interactions of compounds with target enzyme were evaluated through docking studies. Resistance profiling of bacterical clinical isolates (MDRs) depicted that some standard drugs used were not active against these MDRs while our synthesized compounds showed good MIC values. Among all the synthesized compounds, 2a and 2b showed significant antibacterial potential towards gram-positive Staphylococcus epidermidis and gram-negative Pseudomonas aeruginosa at MIC 250 µg/mL and 375 µg/mL respectively. Likewise, compound 2d and 2g exhibited inhibitory potential against gram-positive Staphylococcus aureus and gram-negative Escherichia coli at MIC values of 250 and 375 µg/mL respectively. Compound 2b showed maximum antifungal potential against Candida glabrata (ATCC 62934) with a zone of inhibition 21.0 mm as compared to the reference drug nystatin which showed lesser antifungal potential with a zone of inhibition of 19.1 mm. Candida albicans (ATCC 60387) showed maximum sensitivity to compound 2a with a zone of inhibition 20.0 mm. Its antifungal activity is more in comparison to reference drug nystatin with exhibited the zone of inhibition of 19.3 mm. Designed compounds were docked with the target enzyme UDP-N-acetylmuramate/l-alanine ligase. The compound 2b showed highest binding affinity (− 7.6 kcal/mol). The synthesized compounds showed moderate to significant antibacterial and antifungal potential. It is clear from the binding affinities that compounds having hydroxyl group substituted on benzene ring possess strong binding affinity as compared to other analogues. These designed compounds could be considered to act as antagonists against target UDP-N-acetylmuramate/l-alanine ligase.

  • Design, efficient synthesis and molecular docking of some novel thiazolyl-pyrazole derivatives as anticancer agents
    BMC Chem. (IF 2.284) Pub Date : 2019-09-24
    Abdelwahed R. Sayed; Sobhi M. Gomha; Fathy M. Abdelrazek; Mohamed S. Farghaly; Shaimaa A. Hassan; Peter Metz

    Pyrazoles, thiazoles and fused thiazoles have been reported to possess many biological activities. 3-Methyl-5-oxo-4-(2-arylhydrazono)-4,5-dihydro-1H-pyrazole-1-carbothioamides 3a,b (obtained from the reaction of ethyl 3-oxo-2-(2-arylhydrazono)butanoates 1a,b with thiosemicarbazide) could be transformed into a variety of thiazolyl-pyrazole derivatives 6a–h, 10a–c, 15a–c, 17, 19 and 21 via their reaction with a diversity hydrazonoyl chlorides as well as bromoacetyl derivatives. Moreover, the computational studies were carried out for all new compounds. The results indicated that five compounds showed promising binding affinities (10a: − 3.4 kcal/mol, 6d: − 3.0 kcal/mol, 15a: − 2.2 kcal/mol, 3a: − 1.6 kcal/mol, and 21: − 1.3 kcal/mol) against the active site of the epidermal growth factor receptor kinase (EGFR). The cytotoxicity of the potent products 3a, 6d, 10a, 15a, and 21 was examined against human liver carcinoma cell line (HepG-2) and revealed activities close to Doxorubicin standard drug. There was an understanding between the benefits of restricting affinities and the data obtained from the practical anticancer screening of the tested compounds.

  • Construction of a novel quinoxaline as a new class of Nrf2 activator
    BMC Chem. (IF 2.284) Pub Date : 2019-09-24
    Murugesh Kandasamy; Kit-Kay Mak; Thangaraj Devadoss; Punniyakoti Veeraveedu Thanikachalam; Raghavendra Sakirolla; Hira Choudhury; Mallikarjuna Rao Pichika

    The transcription factor Nuclear factor erythroid-2-related factor 2 (NRF2) and its principal repressive regulator, Kelch-like ECH-associated protein 1 (KEAP1), are perilous in the regulation of inflammation, as well as maintenance of homeostasis. Thus, NRF2 activation is involved in cytoprotection against many inflammatory disorders. N′-Nicotinoylquinoxaline-2-carbohdyrazide (NQC) was structurally designed by the combination of important pharmacophoric features of bioactive compounds reported in the literature. NQC was synthesised and characterised using spectroscopic techniques. The compound was tested for its anti-inflammatory effect using Lipopolysaccharide from Escherichia coli (LPSEc) induced inflammation in mouse macrophages (RAW 264.7 cells). The effect of NQC on inflammatory cytokines was measured using enzyme-linked immune sorbent assay (ELISA). The Nrf2 activity of the compound NQC was determined using ‘Keap1:Nrf2 Inhibitor Screening Assay Kit’. To obtain the insights on NQC’s activity on Nrf2, molecular docking studies were performed using Schrödinger suite. The metabolic stability of NQC was determined using mouse, rat and human microsomes. NQC was found to be non-toxic at the dose of 50 µM on RAW 264.7 cells. NQC showed potent anti-inflammatory effect in an in vitro model of LPSEc stimulated murine macrophages (RAW 264.7 cells) with an IC50 value 26.13 ± 1.17 µM. NQC dose-dependently down-regulated the pro-inflammatory cytokines [interleukin (IL)-1β (13.27 ± 2.37 μM), IL-6 (10.13 ± 0.58 μM) and tumor necrosis factor (TNF)-α] (14.41 ± 1.83 μM); and inflammatory mediator, prostaglandin E2 (PGE2) with IC50 values, 15.23 ± 0.91 µM. Molecular docking studies confirmed the favourable binding of NQC at Kelch domain of Keap-1. It disrupts the Nrf2 interaction with kelch domain of keap 1 and its IC50 value was 4.21 ± 0.89 µM. The metabolic stability studies of NQC in human, rat and mouse liver microsomes revealed that it is quite stable with half-life values; 63.30 ± 1.73, 52.23 ± 0.81, 24.55 ± 1.13 min; microsomal intrinsic clearance values; 1.14 ± 0.31, 1.39 ± 0.87 and 2.96 ± 0.34 µL/min/g liver; respectively. It is observed that rat has comparable metabolic profile with human, thus, rat could be used as an in vivo model for prediction of pharmacokinetics and metabolism profiles of NQC in human. NQC is a new class of NRF2 activator with potent in vitro anti-inflammatory activity and good metabolic stability.

  • Two novel UPLC methods utilizing two different analytical columns and different detection approaches for the simultaneous analysis of velpatasvir and sofosbuvir: application to their co-formulated tablet
    BMC Chem. (IF 2.284) Pub Date : 2019-09-30
    Moustapha Eid Moustapha; Rania Mohamed El-Gamal; Fathalla Fathalla Belal

    In the present study two different RSLC columns, Acclaim RSLC 120 C18, 5.0 µm, 4.6 × 150 mm (column A) and Acclaim RSLC 120 C18, 2.2 µm, 2.1 × 100 mm (Column B) were utilized for the analysis of velpatasvir (VPS) in presence of sofosbuvir (SFV), where due to the encountered fluorescent properties of VPS fluorescent detection at 405 nm after excitation at 340 nm (Method 1) was used for its detection where the non-fluorescent SFV did not interfere. The same columns were further utilized for the simultaneous determination of SFV and VPS either in bulk form or in their combined tablet, where UV- spectrophotometric detection at 260 nm was selected for the simultaneous analysis of both drugs (Method 2). A mobile phase consisting of NaH2PO4, pH 2.5 (with phosphoric acid) and acetonitrile in a ratio of 60:40 v/v was used for both methods. The mobile phase was pumped at a flow rate of 1.0 mL/min when using column, A and 0.5 mL/min when using column B. The methods showed good linearity over the concentration ranges of 1.0–5.0 and 2.5–10.0 ng/mL for VPS when utilizing Method 1 A and B respectively. Where the linearity concentration range was from 30.0–150.0 to 120–600.0 ng/mL for VPS and SFV respectively when applying Method 2. Both methods 1 and 2 were performed by utilizing the two analytical columns. The different chromatographic parameters as retention time, resolution, number of theoretical plates (N), capacity factor, tailing factor and selectivity were carefully optimized. The results show that comparing the performance of the two utilized columns revealed that shorter column (2.1 mm × 100 mm) with small particle packing was superior to the longer column (4.6 × 150 mm) for the analysis of the studied drugs allowing a reduction of the analysis time by 70% without any detrimental effect on performance. This prompts the decrease of the investigation costs by saving money on organic solvents and expanding the overall number of analyses per day.

  • Green synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles] using Fe3O4@l-arginine as a robust and reusable catalyst
    BMC Chem. (IF 2.284) Pub Date : 2019-10-11
    Mohammad Ali Ghasemzadeh; Boshra Mirhosseini-Eshkevari; Mohammad Hossein Abdollahi-Basir

    The synthesized Fe3O4@l-arginine showed strong catalytic performance in the one-pot synthesis of spiropyranopyrazoles via the reactions of hydrazines, β-keto esters, isatins, and malononitrile or ethyl cyanoacetate under solvent-free conditions. The biologically active heterocyclic compounds including spiropyranopyrazole derivatives were efficiently synthesized in short reaction times and excellent yields in the presence of Fe3O4/l-arginine at room temperature. The highlighted features of the Fe3O4@l-arginine nanocomposite are highly stable, easy to separate, low loading, cost-effective with easy preparation and reusability of the catalyst. The heterogeneous nanocomposite was fully characterized by SEM, EDX, FT-IR, XRD and TEM analysis.

  • Crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) tethered to nano-Fe3O4 as a superior catalyst for the synthesis of 1,3-thiazoles
    BMC Chem. (IF 2.284) Pub Date : 2019-10-12
    Hossein Shahbazi-Alavi; Sheida Khojasteh-Khosro; Javad Safaei-Ghomi; Maryam Tavazo

    Crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4 as a superior catalyst has been used for the synthesis of 3-alkyl-4-phenyl-1,3-thiazole-2(3H)-thione derivatives through a three-component reactions of phenacyl bromide or 4-methoxyphenacyl bromide, carbon disulfide and primary amine under reflux condition in ethanol. A proper, atom-economical, straightforward one-pot multicomponent synthetic route for the synthesis of 1,3-thiazoles in good yields has been devised using crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) tethered to nano-Fe3O4. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), dynamic light scattering (DLS), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA) and vibrating-sample magnetometer (VSM).

  • New potentiometric sensors for methylphenidate detection based on host–guest interaction
    BMC Chem. (IF 2.284) Pub Date : 2019-10-14
    Haitham AlRabiah; Mohammed Abounassif; Haya I. Aljohar; Gamal Abdel-Hafiz Mostafa

    The study aims to develop simple, sensitive, and selective methods for detecting methylphenidate in its bulk, dosage form and human urine. Sensing materials include β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), and 4-tertbutylcalix[8]arene as ionophores or electroactive materials have been used for construction of sensors 1, 2, and 3, respectively; Potassium tetrakis (4-chlorophenyl)borate (KTpClPB) as an ion additive was used and dioctyl phthalate as a plasticizer. The sensors displayed a fast, stable response over a wide concentration range of methylphenidate (8 × 10−6 M to 1 × 10−3 M) with 10−6 M detection limit over the pH range of 4–8. The developed sensors displayed a Near-Nernstian cationic response for methylphenidate at 59.5, 51.37, and 56.5 mV/decade for sensors β-CD, γ-CD, or 4-tertbutylcalix[8]arene respectively. Validation of the proposed sensors is supported by high accuracy, precision, stability, fast response, and long lifetimes, as well as selectivity for methylphenidate in the presence of different species. Sensitive and practical sensors for the determination of methylphenidate in bulk, in pharmaceutical forms and urine were developed and validated for routine laboratory use. The results were comparable to those obtained by HPLC method.

  • A rapid and sensitive UPLC-MS/MS method for the determination of flibanserin in rat plasma: application to a pharmacokinetic study
    BMC Chem. (IF 2.284) Pub Date : 2019-08-27
    Long He; Wenting You; Sa Wang; Tian Jiang; Caiming Chen

    In this work, we aim to develop and validate a fast, simple, and sensitive method for the quantitative determination of flibanserin and the exploration of its pharmacokinetics. Ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was the method of choice for this investigation and carbamazepine was selected as an internal standard (IS). The plasma samples were processed by one-step protein precipitation using acetonitrile. The highly selective chromatographic separation of flibanserin and carbamazepine (IS) was realised using an Agilent RRHD Eclipse Plus C18 (2.1 × 50 mm, 1.8 µ) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. The analytes were detected using positive-ion electrospray ionization mass spectrometry via multiple reaction monitoring (MRM). The target fragment ions were m/z 391.3 → 161.3 for flibanserin and m/z 237.1 → 194 for carbamazepine (IS). The method was validated by linear calibration plots over the range of 100–120,000 ng/mL for flibanserin (R2 = 0.999) in rat plasma. The extraction recovery of flibanserin was in the range of 91.5–95.8%. The determined inter- and intra-day precision was below 12.0%, and the accuracy was from − 6.6 to 12.0%. No obvious matrix effect and astaticism was observed for flibanserin. The target analytes were long-lasting and stable in rat plasma for 12 h at room temperature, 48 h at 4 °C, 30 days at − 20 °C, as well as after three freeze–thaw cycles (from − 20 °C to room temperature). The proposed method has been fully validated and successfully applied to the pharmacokinetic study of flibanserin.

  • Atom transfer radical polymer-modified paper for improvement in protein fixation in paper-based ELISA
    BMC Chem. (IF 2.284) Pub Date : 2019-08-22
    Lu Qi; Aihong Zhang; Yu Wang; Long Liu; Xinghe Wang

    A newly modified paper-based enzyme-linked immunosorbent assay (P-ELISA) was established by immobilizing more proteins on the paper surface through an atom transfer radical polymerization (ATRP) reaction. In addition, introducing graphene oxide (GO) sheets, Au nanoparticles (AuNps) and two primary antibodies (Ab1s) led to signal amplification and cost reduction.

  • Design, synthesis, and preliminary biological evaluation of catalpol propionates as antiaging drugs
    BMC Chem. (IF 2.284) Pub Date : 2019-08-21
    Chunhong Dong; Shuanglin Liu; Xiaodong Cheng; Qiang Wang; Shiqing Jiang; Guoqing Wang

    In this paper, catalpol propionylated analogs (CPs) were designed as drug ligands of glutathione peroxidase (GSH-Px) based on molecular docking (MD) using Surflex-Docking method. The calculated total scores (Total_score) and C log P of CPs are higher than that of catalpol, which show that the CPs maybe served as potential lead compounds as new antiaging drugs. Furthermore, the maximum Total_score of isomers in one group CPs is often not that the molecule with minimum energy structure. These show that the CPs docking with GSH-Px maybe not only affected by the molecular energy, but also affected by their conformations. The CPs were synthesized by esterification of catalpol with propionic anhydride using pyridine as solvent and acid banding agent, DMAP as catalyst, reaction at specific temperature. The synthesized perpropionylated catalpol analog (CP-6) was determined by NMR, FT-IR, HRMS, and HPLC, and the synthesis process was optimized by means of orthogonal experimental design. Subsequently, CP-6 was screened for cells viability by MTT assay, the results show that the CP-6 can effectively reversed STZ-induced reduction of cells viability, and CP-6 has potential antiaging activity.

  • Thermodynamic properties of some isomeric 5-(nitrophenyl)-furyl-2 derivatives
    BMC Chem. (IF 2.284) Pub Date : 2019-08-14
    Volodymyr Dibrivnyi; Andriy Marshalek; Iryna Sobechko; Yuriy Horak; Mykola Obushak; Nadiia Velychkivska; Lubomyr Goshko

    The aim of the current work was to determine thermodynamical properties of 5-(nitrophenyl)-2-furaldehyde oximes and 3-[5-(nitrolphenyl)-2-furyl]acrylic acids. The temperature dependences of saturated vapor pressures of 5-(nitrophenyl)-2-furaldehyde oximes and 3-[5-(nitrolphenyl)-2-furyl]acrylic acids were determined by the Knudsen effusion method. The results are presented by the Clapeyron–Clausius equation in linear form, and via this form, the standard enthalpies of sublimation of compounds were calculated at 298.15 K. The standard molar formation enthalpies of compounds in crystalline state at 298.15 K were determined indirectly from the corresponding standard molar combustion enthalpy, obtained using combustion bomb calorimetry. The non-nearest neighbour interactions (strain) in molecule were defined. The ideal-gas enthalpies of investigated compounds formation and the data available from the literature were used for calculation of group-additivity parameters and the correction terms useful in the application of the Benson correlation. Determining the thermodynamic properties for these compounds will contribute to solving practical problems pertaining to optimization processes of their synthesis, purification and application. It will also provide a more thorough insight regarding the theoretical knowledge of their nature and are necessary for the application of the Benson group-contribution correlation for calculation of $$ \Delta {}_{f}H_{{m(298.15{\text{K}})}}^{o} $$ Δ f H m ( 298.15 K ) o (g)calc.

  • A review of bioanalytical techniques for evaluation of cannabis (Marijuana, weed, Hashish) in human hair
    BMC Chem. (IF 2.284) Pub Date : 2019-08-14
    Iltaf Shah; Bayan Al-Dabbagh; Alaa Eldin Salem; Saber A.A. Hamid; Neak Muhammad; Declan P. Naughton

    Cannabis products (marijuana, weed, hashish) are among the most widely abused psychoactive drugs in the world, due to their euphorigenic and anxiolytic properties. Recently, hair analysis is of great interest in analytical, clinical, and forensic sciences due to its non-invasiveness, negligible risk of infection and tampering, facile storage, and a wider window of detection. Hair analysis is now widely accepted as evidence in courts around the world. Hair analysis is very feasible to complement saliva, blood tests, and urinalysis. In this review, we have focused on state of the art in hair analysis of cannabis with particular attention to hair sample preparation for cannabis analysis involving pulverization, extraction and screening techniques followed by confirmatory tests (e.g., GC–MS and LC–MS/MS). We have reviewed the literature for the past 10 years’ period with special emphasis on cannabis quantification using mass spectrometry. The pros and cons of all the published methods have also been discussed along with the prospective future of cannabis analysis.

  • Treatment and characterization of phosphorus from synthetic wastewater using aluminum plate electrodes in the electrocoagulation process
    BMC Chem. (IF 2.284) Pub Date : 2019-08-14
    Dessie Tibebe; Yezbie Kassa; Ashok N. Bhaskarwar

    The main objective of this study is treatment and characterization of phosphorus from synthetic wastewater using aluminum electrodes in the electrocoagulation process. EC experimental setups were designed and different parameters were optimized. The maximum amounts of phosphorus removal efficiencies were observed at pH 7. The phosphorus removal efficiency increases from 85.16 to 97.65% as the temperature increases from 15 to 45 °C, beyond this temperature, there is small effect on removal efficiency. Pollutant removal efficiency increases with an increase in the electrolysis time. At lower initial concentrations the removal efficiencies reached to their maximum values while at the highest initial concentration, the phosphorus removal efficiency was decreased. The increase of current density improves the efficiency of phosphorus removal. Energy and aluminum consumption decreases with increasing initial concentration of phosphorus. Field Emission Scanning Electron Microscope (FESEM) image analysis demonstrated very fine structures for aluminum hydroxide/oxyhydroxides and aluminum phosphate. The existence of the different elemental composition in the sludge was proved by the help of Energy Dispersive X-ray Analysis (EDXS), indicating that the aluminum, oxygen and phosphorus were present in the product. From X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and Raman analyses of the sludge product, it is concluded that the chemical speciation of the by-products can be mostly aluminum hydroxide and aluminum phosphate.

  • Chemical constituents and coagulation activity of Syringa oblata Lindl flowers
    BMC Chem. (IF 2.284) Pub Date : 2019-08-14
    Lili Cui; Miyun Hu; Pengran Cao; Yun Niu; Changqin Li; Zhenhua Liu; Wenyi Kang

    The leaves and bark of Syringa oblata Lindl are used as folk medicine which has heat-clearing, detoxifying, dampness-removing and jaundice-relieving effects. There are many studies about leaves of S. oblata because of its abundant resource, however, less reports about the components of S. oblata flowers. The previous studies on S. oblate flowers were mainly focused on the volatile components and its traditional pharmacological activity. Thus, this study aimed to investigate the nonvolatile chemical constituents and the coagulation activity of S. oblate flowers. The chemical constituents of S. oblate flowers were isolated with various column chromatographies and coagulation activity of the major constituents was investigated by assaying the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen (FIB) on plasma of rabbit in vitro. Fifteen known compounds (namely compound 1-15) were isolated from S. oblata flowers. Compound 6, 10, 11 and 14 were isolated from Syringa genus for the first time. Compound 1, 2, 4, 5, 8 and 9 were isolated from the plant for the first time. The results of coagulation activity showed that water part of S. oblate flowers, lauric acid and kaempferol-rutinose significantly shorten PT (P < 0.001), TT (P < 0.001) and APTT (P < 0.001) compared with blank group, thus revealed that water extract of S. oblate flowers, lauric acid and kaempferol-rutinose possessed the procoagulant activity, but the effects were not better than that of Yunnan Baiyao as positive control.

  • Protective effect of blackthorn fruits (Prunus spinosa) against tartrazine toxicity development in albino Wistar rats
    BMC Chem. (IF 2.284) Pub Date : 2019-08-09
    Igori Balta; Bogdan Sevastre; Vioara Mireşan; Marian Taulescu; Camelia Raducu; Adina Lia Longodor; Zamfir Marchiş; Codruta Stefania Mariş; Aurelia Coroian

    Tartrazine (Yellow 5 or E102) is a synthetic food dye able to modify perception and behavior, causing agitation, confusion, rhinitis and can produce hyperactivity syndrome in children when is combined with benzoates. Additionally, it can trigger oxidative stress which consequently generates metabolic disorders. Therefore, the study was designed to evaluate the harmful effects of the food additive tartrazine and to observe beneficial properties of blackthorn fruits (Prunus spinosa) on the blood and organs of albino Wistar rats. This study was carried out on 20 mature Wistar rats, randomly divided into four groups of five animals. Over the course of the experiment, the control group received only food and drinking water, group I received 75 mg of tartrazine dissolved in (250 ml) water group II was given 75 mg of tartrazine and 200 mg of dried blackthorn fruit powder 200 mg dissolved simultaneously in (250 ml) of tartrazine-water mixture (aiming to reduce the tartrazine toxicity) and group III received a higher dose of tartrazine (100 mg) in (250 ml) of water. At the end of the experiment, values regarding kidney and liver weight were significantly increased, while the weight of the spleen was slightly decreased compared with the weight of the control group. Biochemical and hematological assays, of the blood samples show that the addition of tartrazine in the diet of rats caused significant changes in all biochemical and hematological parameters of the blood. In the group II, which received (P. spinosa) powder combined with tartrazine, the biochemical and hematological parameters had average values similar to the control group. Histopathological assay showed that the application of tartrazine in the group I, II and III produced lesions of the kidneys, spleen and the liver for all rodents. Tartrazine was able to generate histopathological changes, which caused significantly tissue lesions of the liver and significant changes in blood parameters. Blackthorn powder showed a promising protective role for the blood parameters but demonstrated no significant benefits for the organs.

  • Secondary metabolites from the Aspergillus sp. in the rhizosphere soil of Phoenix dactylifera (Palm tree)
    BMC Chem. (IF 2.284) Pub Date : 2019-08-07
    Raha Orfali; Shagufta Perveen

    The soil-derived fungus Aspergillus sp. isolated from the rhizospheric soil of Phoenix dactylifera (Date palm tree) and cultured on the large scale solid rice medium yielded a novel compound 1-(4-hydroxy-2,6-dimethoxy-3,5-dimethylphenyl)-2-methyl-1-butanone (1) and four known compounds; citricin (2), dihydrocitrinone (3), 2, 3, 4-trimethyl-5, 7-dihydroxy-2, 3-dihydrobenzofuran (4) and oricinol (5). The structures of the isolated compounds were elucidated by MS, 1H, 13C and 2D NMR spectra. Compound (1) exhibited potent antimicrobial activities against Staphylococcus aureus with MIC values of 2.3 μg mL−1 and significant growth inhibitions of 82.3 ± 3.3 against Candida albicans and of 79.2 ± 2.6 against Candida parapsilosis. This is the first report to isolate metabolites from the fungus Aspergillus found in temperate region date plant rhizospheres.

  • Three smart spectrophotometric methods for resolution of severely overlapped binary mixture of Ibuprofen and Paracetamol in pharmaceutical dosage form
    BMC Chem. (IF 2.284) Pub Date : 2019-08-06
    Christine M. El-Maraghy; Nesrine T. Lamie

    Paracetamol is an analgesic-antipyretic drug and Ibuprofen is a non-steroidal anti-inflammatory drug. They are co-formulated as tablets to improve analgesia, to simplify prescribing and to improve patient compliance. Three accurate, simple and sensitive spectrophotometric methods were developed for the simultaneous determination of Paracetamol and Ibuprofen in their co-formulated dosage form. The first method was the ratio difference, which was based on the measurement of the difference in absorbance between the two wavelengths (210.6 and 216.4 nm) for Ibuprofen and (236.0 and 248.0 nm) for Paracetamol. The second method was constant center method which depends on using the constant found in the ratio spectra. The third method was the mean centering of ratio spectra which measured the manipulated values at 240 nm and 237 nm for Ibuprofen and Paracetamol, respectively. Beer’s law was obeyed in the concentration range of 2–50 μg/mL for Ibuprofen and 2–20 μg/mL for Paracetamol. The recovery % of the accuracy of both methods ranged from 99.64 to 100.56%. Factors affecting the resolution of the spectra were studied and optimized. The three methods are validated according to ICH guidelines and could be applied for the pharmaceutical preparation.

  • Identification of novel antifungal agents: antimicrobial evaluation, SAR, ADME–Tox and molecular docking studies of a series of imidazole derivatives
    BMC Chem. (IF 2.284) Pub Date : 2019-08-06
    Btissam Bouchal; Farid Abrigach; Abdelilah Takfaoui; Manal Elidrissi Errahhali; Mounia Elidrissi Errahhali; Pierre H. Dixneuf; Henri Doucet; Rachid Touzani; Mohammed Bellaoui

    Thirty-four imidazole-based compounds synthesized by one-pot catalytic method were evaluated for their antifungal and antibacterial activities against several fungal and bacterial strains. None of the compounds had antibacterial activity. Interestingly, compounds 1, 2, 3, 10 and 15 displayed a strong antifungal activity against all the tested fungal species, while compounds 5, 7, 9, 11, 21 and 27 showed a moderate antifungal activity. To better understand the biological activity of the most active compounds ADME–Tox and molecular docking studies were carried out. Interestingly, compounds 1, 2, 3, 7, 10 and 15 showed excellent bioavailability. In addition, compounds 1, 2 and 3, exhibited good toxicity profiles. Docking studies of the two most active compounds 2 (IC50 of 95 ± 7.07 μM) and 10 (IC50 of 235 ± 7.07 μM) suggested that they might act by inhibiting the fungal lanosterol 14α-demethylase. Therefore, these novel antifungal agents merit further characterization for the development of new antifungal therapeutics.

  • Pharmacological significance of heterocyclic 1H-benzimidazole scaffolds: a review
    BMC Chem. (IF 2.284) Pub Date : 2019-08-06
    Sumit Tahlan; Sanjiv Kumar; Balasubramanian Narasimhan

    Heterocyclic compounds are inevitable in a numerous part of life sciences. These molecules perform various noteworthy functions in nature, medication and innovation. Nitrogen-containing heterocycles exceptionally azoles family are the matter of interest in synthesis attributable to the way that they happen pervasively in pharmacologically dynamic natural products, multipurpose arranged useful materials also profoundly powerful pharmaceuticals and agrochemicals. Benzimidazole moiety is the key building block for several heterocyclic scaffolds that play central role in the biologically functioning of essential molecules. They are considered as promising class of bioactive scaffolds encompassing diverse varieties of activities like antiprotozoal, antihelminthic, antimalarial, antiviral, anti-inflammatory, antimicrobial, anti-mycobacterial and antiparasitic. Therefore in the present review we tried to compile the various pharmacological activities of different derivatives of heterocyclic benzimidazole moiety.

  • Synthesis, anti-leishmanial and molecular docking study of bis-indole derivatives
    BMC Chem. (IF 2.284) Pub Date : 2019-08-06
    Muhammad Taha; Imad Uddin; Mohammed Gollapalli; Noor Barak Almandil; Fazal Rahim; Rai Khalid Farooq; Muhammad Nawaz; Mohamed Ibrahim; Mohammed A. Alqahtani; Yasser A. Bamarouf; Manikandan Selvaraj

    We have synthesized new series of bisindole analogs (1–27), characterized by 1HNMR and HR-EI-MS and evaluated for their anti-leishmanial potential. All compounds showed outstanding inhibitory potential with IC50 values ranging from 0.7 ± 0.01 to 13.30 ± 0.50 µM respectively when compared with standard pentamidine with IC50 value of 7.20 ± 0.20 µM. All analogs showed greater potential than standard except 10, 19 and 23 when compared with standard. Structure activity relationship has been also established for all compounds. Molecular docking studies were carried out to understand the binding interaction of active molecules.

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上海纽约大学William Glover