Evaluation of the antimicrobial efficacy of phytogenic silver nanoparticles

To evaluate the antimicrobial activity of silver nanoparticles synthesized from Psidium guajava (P. guajava) against human pathogens. Ultraviolet-visible (UV-Vis) spectrophotometry and transmission electron microscopy (TEM) were performed to confirm the formation and stability of silver nanparticles. Antimicrobial activities of the synthesized Ag nanoparticles were determined using the agar well diffusion assay method. UV-Vis spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 410 nm. TEM showed the formation of silver nanoparticles with an average size of 59 nm. The formed silver nanoparticles showed good antimicrobial activity against Escherichia coli, Bacillus cereus and Candida tropicalis. P. guajava demonstrated strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag + to Ag 0). Biological methods are a good competent for the chemical procedures, which are environment friendly and convenient.