Bactericidal effect of silver nanoparticles from aqueous root extracts of Catharanthus roseus

In this study, green synthesis of silver nanoparticle (AgNPs) is synthesised using aqueous root extract of Catharanthus roseus as a reducing as well as capping agent. The bioactive molecules present in the root extract such as alkaloids, flavonoids, carbohydrates, amino acids and phenolic compounds were found to be responsible for the reducing and capping of nanoparticles. Stable nanoparticles were observed after the addition of aqueous root extract into the silver nitrate solution. Biotransformation of the silver nitrate to silver nanoparticles were investigated by UV-visible spectroscopy (UV) and found that the surface plasmon resonance of the nanoparticles is a shallow peak at 490 nm. XRD pattern shows the crystalline nature of silver nanoparticle. Highly mono dispersed silver nanoparticles within 100 nm rage was revealed from TEM. The activity of the silver nanoparticles against microbes were found to be higher in the zone of inhibition in all the species used for the studies.