Synthesis of silver nanoparticles using Senna sophera (L.) Roxb. leaf extract and study of antibacterial and anti-cancer properties

The present study aimed to synthesise silver nanoparticles using an aqueous leaf extract of Senna sophera (L.) Roxb. (Fabaceae) to evaluate their antioxidant, antibacterial and anticancer activity. The silver nanoparticles (AgNPs) produced were characterized by different spectroscopic and microscopic techniques namely; UV-Vis spectroscopy, FTIR, DLS, XRD and TEM. The prominent peak at 424 nm in UV-Vis spectroscopy confirms the synthesis of nanoparticles, FTIR spectra confirms the presence of polyphenols and proteins from the leaf extract which mainly acts as reducing, capping and stabilizing agent. DLS results confirm the negative value of zeta potential and the XRD results revealed that the AgNPs are crystalline in nature with a face-centered cubic nature. TEM micrograph images indicate that the nanoparticles are 5-35 nm without any agglomeration. EDX result revealed that the weight % of nanoparticles is 69.56 %, indicating the purity of the sample. Biosynthesized AgNPs show effective DPPH, H2O2 scavenging activity and FRAP assay. AgNPs show strong antibacterial activity against Escherichia coli, Klebsiella pneumonia, Salmonella typhi, Bacillus subtilis and Staphylococcus aureus with an inhibition zone of 17.6, 16.03, 15.66, 14.13 and 12.33 mm respectively. The antibacterial activity of leaf aqueous extract at different concentrations of AgNPs revealed the efficacy against Salmonella typhi. Further AgNPs exhibited good cytotoxic properties against HepG2 cell line with the IC50 value of 95.52 mu g/mL. The silver nanoparticles were successfully synthesized using Senna sophera leaf extract, proving it to be an economical, environmentally benign and sustainable method for its applications in pharmaceutical field.