Silver nanoparticles fabricated using medicinal plant extracts show enhanced antimicrobial and selective cytotoxic propensities

Nanoparticles fabricated using medicinal plant extract have great potential in the area of nanomedicine. High surface-to-volume ratio of nanoparticle enhances the local active biomolecules concentration, leading to many fold increase in the medicinal potentials. The silver nanoparticles (AgNPs) fabricated using indigenous medicinal plants of India, Azadirachta indica and Syzygium cumini, have shown a significant effect on the viability of prokaryotic and eukaryotic cells. Biofabrication of AgNP was confirmed using different spectroscopic and microscopic techniques. Extraction and purification of AgNP from non-conjugated plant moieties are done using centrifugation and size exclusion chromatography. The cytotoxic propensity of AgNP formulations was screened against Gram-positive (Bacillus subtilis), Gram-negative (Escherichia coli) bacteria, cancerous (HT1080) and non-cancerous (HEK293) cell lines. The nanoparticle formulations showed a relatively higher cytotoxic propensity against Gram-positive bacteria and cancerous cell lines. In addition, the surface roughness and reactive oxygen species (ROS) measurements indicated that AgNP formulations mediate the cell activity predominantly by ROS-mediated disruptive change in membrane morphology upon direct interaction with the membrane. Hence, the nanoparticle formulations show an enhanced selective cytotoxic propensity towards Gram-positive bacteria and cancerous cell lines.