Green and cost effective synthesis of silver nanoparticles from endangered medicinal plant Withania coagulans and their potential biomedical properties.

Silver nanoparticles (AgNPs) have great potential for their mechanistic role in biomedical researches. Recently, green biosynthetic approaches have been received much attention in plant science for nanoparticles production. Therefore, in the present study AgNPs have been synthesized utilizing in-vitro grown leaf extract of anti-diabetic medicinal plant Withania coagulans Dunal by the reduction of silver nitrate solution. W. coagulans synthesized silver nanoparticles (WcAgNPs) were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, X-ray powder diffraction and Fourier transform Infra-Red spectroscopy. All cumulative results showed that WcAgNPs were ~14 nm in size having spherical shape with face centered cubic structure. High performance liquid chromatography confirmed the involvement of withanolides in AgNPs synthesis as a reducing/capping agent. Synthesized WcAgNPs showed greater antioxidative potential when compared with W. coagulans leaf extract. WcAgNPs have efficient antimicrobial potential and suppresses the growth of both gram positive and gram negative bacteria. In our finding we also observed cytotoxicity of WcAgNPs against SiHa (cervical cancerous, hyper-triploid) cell lines and apoptosis in SiHa cells after 48 hour incubation with 13.74 μg ml-1 (IC50) concentration of WcAgNPs. As results suggested, this is the first report which explain that W. coagulans leaf extract have potential as bio-reducing agent for synthesis of silver nanoparticles, which can be exploited as anti-oxidant, antimicrobial and anti-cancerous agent and depicting an effective way for utilizing bioactive resources in restoration of medicinal properties of this plant with high efficacy.