Green synthesis and characterization of silver nanoparticles using leaves extract of Neem (Azadirachta indica L.) and assessment of its in vitro antioxidant and antibacterial activity

There is an increased demand for environment friendly non-toxic synthetic biological protocol for the synthesis of nanoparticles. The investigation was aimed to synthesize silver nanoparticles using leaves extract of Neem (Azadirachta indica L.), its characterization and assessment of in vitro antioxidant and antibacterial activity. Aqueous extract of the plant was used and synthesis of nanoparticles are confirmed by the colour change, followed by UV-Vis spectro photo meter analysis. The zeta potential measurement of the nanoparticles are found to be - 48.9 mV and found stable. The synthesized nanoparticles are almost spherical in shape in SEM micrograph. In TEM analysis, the average size of the nanoparticles was found to be 38.54 +/- 2.94 nm. It may be concluded that the leaves extract of the plant is found suitable for synthesis of silver nanoparticles, showed sensitive response against both grampositive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli). The antioxidant activity of the nanoparticles was also found higher than the extract alone.