Article Subject

There is worldwide interest in silver nanoparticles (AgNPs) synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis) of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Withania coagulans extract is a medicinal agent with multiple properties including an antibacterial and anti oxidant activity. AgNPs were prepared by an eco-friendly hydrothermal method using a Withania coagulans plant extract solution as both a reducing and stabilizing agent. The synthesized nano particles was characterized using UV, IR XRD, TEM and SEM. Additionally, an agar disc diffusion method was used to screen for antimicrobial activity. Then the anti oxidant activity was investigated using DPPH assay method. The synthesized AgNPs were crystalline with sizes of 20-150nm as revealed using XRD and SEM. The particles were found to be Cubic and Spherical in shape.

These AgNPs were investigated for potential use as an antibacterial and anti fungal agent to inhibit growth of pathogenic bacteria and fungi. Very high bacterial zone inhibition activity was observed on B Subtilis, B cereus and E coli. Anong the two fungal strains observed, the AgNPs show very high activity against the growth of A niger. The LC50 for DPPH activity was observed at a very low concentration 50-100µg/mL. This confirms that the syntheisised nano particles were found to have high anti oxidant activity. These results indicated that AgNPs synthesized using Withania coagulans extract can be effectively utilized inpharmaceutical, biotechnological and biomedical applications

Green synthesis; Withania coagulans
Nanoparticle tracking analyzer
Transmission electron microscope; Energy dispersive X-ray spectra