Antibacterial activity of silver nanoparticles synthesized using weeds

Biologically synthesized silver nanoparticles are being widely used in the field of medicine. This report focuses on extracellular biosynthesis of silver nanoparticles using leaf extracts of four commonly occurring weed. The synthesis of silver nanoparticles was detected by changing colour of plant leaf extracts from green to brown after treatment with AgNO₃ and UV-Vis spectrophotometric analysis. These phyto-synthesized silver nanoparticles were tested for their antibacterial activity using agar well diffusion method. The test bacteria were E. coli, Staphylococcus aureus and Bacillus sp. Among all the test organisms Bacillus sp. followed by Staphylococcus aureus were found to be susceptible to all the silver nanoparticles with maximum inhibition by Sonchus asper whereas E. coli was least affected. The results suggest use of phytoextracts as an easy alternative for silver nanoparticles synthesis over the conventional methods.