Silver nanoparticles (AgNPs) previously synthesised using leaf (AgNP-L) and stem (AgNP-S) extracts of Clinacanthus nutans (C. nutans) were tested to evaluate antimicrobial, antioxidant, and cytotoxicity activities. The AgNPs showed good inhibition against bacteria, but not fungi. The inhibition results showed the highest activity against Staphylococcus aureus (S. aureus) with 11.35 mm (AgNP-L) and 11.52 mm (AgNP-S), while the lowest inhibition was against Escherichia coli (E. coli) with 9.22 mm (AgNP-L) and 9.25 mm (AgNP-S) in the disc diffusion method. The same trend of results was noted in the well diffusion method. The IC₅₀ of AgNP-L and AgNP-S in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays was 417.05 μg/mL and 434.60 μg/mL, as well as 304.31 μg/mL and 326.83 μg/mL, respectively. Ferric reducing power (FRAP) assay showed that AgNP-L [872.389 μmol/L Fe(II)] and AgNP-S [612.770 μmol/L Fe(II)] exhibited significantly ( < 0.05) greater antioxidant activities than leaf extract (CNL) [152.260 μmol/L Fe(II)] and stem extract (CNS) [110.445 μmol/L Fe(II)] of C. nutans. The AgNPs were also proven to possess cytotoxic effects on the breast (MCF-7), cervical (HeLa), and colon (HT-29) cancer cells in a dose-dependent manner. AgNP-S and AgNP-L showed significantly ( < 0.05) higher cytotoxicity against MCF-7 (117.43 μg/mL) and HT-29 (78.47 μg/mL), respectively. In conclusion, the biosynthesised AgNPs from aqueous extract leaves and stem of C. nutans have demonstrated promising potential towards antioxidant, antimicrobial, and cytotoxicity activities.

中文翻译：

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斜触藻的生物银纳米颗粒作为抗氧化剂，具有抗菌和细胞毒性作用

银纳米颗粒（的AgNPs）使用叶（AgNP-L）预先合成和茎（AgNP-S）的提取物Clinacanthus碱草（C.垂穗进行了测试）来评价抗微生物剂，抗氧化剂，和细胞毒性活性。AgNPs显示出对细菌的良好抑制作用，但对真菌没有抑制作用。抑制结果表明，对金黄色葡萄球菌（S. aureus）的活性最高，为11.35 mm（AgNP-L）和11.52 mm（AgNP-S），而对大肠杆菌（E. coli）的抑制作用最低，为9.22 mm（AgNP -L）和9.25 mm（AgNP-S）（采用圆盘扩散法）。在孔扩散法中注意到了相同的结果趋势。IC ₅₀AgNP-L和AgNP-S在2,2-二苯基-1-苦基苯肼（DPPH）和2,2'-连氮基-双（3-乙基苯并噻唑-6-磺酸）的（ABTS）测定为417.05  μ克/毫升和434.60  μ克/毫升，以及304.31  μ克/ mL和326.83  μ克/毫升，分别。铁的还原力（FRAP）分析表明，AgNP-L [872.389  μ摩尔/ L的Fe（II）]和AgNP-S [612.770  μ摩尔/ L的Fe（II）]表现出显著（ <0.05）更大的抗氧化剂比叶提取物的活动（CNL）[152.260  μ摩尔/ L的Fe（II）]和茎提取物（CNS）[110.445  μ摩尔/ L的Fe（II）]的C.垂穗。还证实了AgNP以剂量依赖性方式对乳腺癌（MCF-7），宫颈癌（HeLa）和结肠癌（HT-29）具有细胞毒性作用。AgNP-S和AgNP-L显著显示（ <0.05）对MCF-7的细胞毒性（117.43  μ克/毫升）和HT-29（78.47  μ分别克/毫升）。总之，从水提物叶生物合成的AgNPs和干的C.垂穗已证明对有前途的抗氧化，抗微生物和细胞毒性活动的潜力。