Abstract Malvastrum coromandelianum is widely used in traditional system of medicine for the cure of different ailments. In the present study, two compounds were isolated from the methanol extract and were characterized as tiliroside [kaempferol-3-O-β- d -(6″-E-p-coumaryl) glucopyranoside] and quercetrin (quercetin-3-O-α- l -rhamnopyranoside) based on comprehensive NMR, IR and mass spectral analysis. NMR also showed the presence of trans- and cis-isomers of tiliroside in 3.26:1.00 ratio. The change of NMR solvent from CH3OH-d4 to DMSO-d6 and resulting chemical shift values have been analyzed. The in vitro IC50 values against 1, 1-diphenyl-2-picryl-hydrazyl radical (DPPH) for tiliroside, quercetrin and extract was found to be 60.40 ± 0.24, 68.05 ± 0.36 and 71.98 ± 0.29 (in µg/mL ± s.d.), respectively. The ferric ion (Fe+3) reducing ability of ethyl acetate extract, tiliroside, quercetrin and standard ascorbic acid were 1.169 ± 0.006, 0.324 ± 0.012, 1.407 ± 0.008 and 1.167 ± 0.010 respectively with R2 > 0.990 at 50 µg/mL concentration. The results conclude that isolated compounds as well as extract have significant antioxidant activity and can be further developed as potential antioxidants.

中文翻译：

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锦葵中顺式和反式叶黄素和槲皮素的综合结构分析及其抗氧化活性

摘要 锦葵在传统医学体系中广泛用于治疗各种疾病。在本研究中，从甲醇提取物中分离出两种化合物，并表征为 tiliroside [kaempferol-3-O-β-d -(6″-Ep-coumaryl) glucopyranoside] 和槲皮素 (quercetin-3-O-α- l -rhamnopyranoside) 基于综合 NMR、IR 和质谱分析。NMR 还显示存在比例为 3.26:1.00 的 tiliroside 的反式和顺式异构体。已分析了 NMR 溶剂从 CH3OH-d4 到 DMSO-d6 的变化以及由此产生的化学位移值。发现 tiliroside、槲皮素和提取物对 1, 1-二苯基-2-苦基-肼基 (DPPH) 的体外 IC50 值为 60.40 ± 0.24、68.05 ± 0.36 和 71.98 ± 0.29（单位为 µg/mL ± sd） ， 分别。在 R90/0.9 µg 浓度下，乙酸乙酯提取物、噻吩草甙、槲皮素和标准抗坏血酸对三价铁离子 (Fe+3) 的还原能力分别为 1.169 ± 0.006、0.324 ± 0.012、1.407 ± 0.008 和 1.167 ± 0.010.9 µg 结果得出结论，分离的化合物以及提取物具有显着的抗氧化活性，可以进一步开发为潜在的抗氧化剂。