Synthesis of Oldenlandia umbellata stabilized silver nanoparticles and their antioxidant effect, antibacterial activity, and bio-compatibility using human lung fibroblast cell line WI-38

Abstract In the past few years, green synthesized silver nanoparticles (AgNPs) are one of predominantly used materials in therapeutics and clinical practices. In this study designed to synthesize AgNPs from aqueous extract of Oldenlandia umbellata and investigate their pharmaceutical properties. UV-Vis spectroscopy of O. umbellata mediated silver nanoparticles (AgNPs@OUa) showed a peak at 423 nm. Fourier transform infrared spectroscopy and phytochemical screening explained the contribution of biomolecules in AgNPs@OUa synthesis. Field emission scanning electron microscope and high-resolution transmission electron microscopy examination revealed that small monodispersed spherical nanoparticles had an average size of 22.7 nm. Antioxidant assays were used to examine antioxidant properties of AgNPs@OUa in comparison with L-ascorbic acid (Vitamin C) as a standard antioxidant. AgNPs@OUa showed dose-dependent antioxidant activities. Antibacterial activities of AgNPs@OUa exhibited the highest zone of inhibition against Streptococcus mutans and Escherichia coli were 16.03 ± 0.35 mm and 19.76 ± 0.25 mm, respectively, at concentration of 1.0 mg L-1). Biocompatibility of AgNPs@OUa against human lung fibroblast (WI-38) cell line was also tested. Even though, the cells treated with the uppermost concentration (100 µg/mL) of AgNPs@OUa, it enhances the cell viability (∼ 90%), suggesting that AgNPs@OUa had no toxicity with excellent biocompatibility.