PHYTOCHEMICAL SCREENING, SILVER NANOPARTICLE SYNTHESIS AND ANTIBACTERIAL STUDIES ON THE LEAVES OF AESCHYNOMENE ASPERA L.

Green synthesis is one of the best routes for the silver nanoparticles (AgNPs). The present study revealed that the aqueous leaf extracts of Aeschynomene aspera, which contains alkaloids, flavonoids, phenols, terpenoids, anthocyanidins, indoles, glycosides, saponins and tannins, is found to be responsible for bioreduction during the synthesis of silver nanoparticles (SNPs). The colour change from light yellow to dark brown within 20 to 60 min indicates the formation of nanoparticles. The UV-Visible spectrum of the aqueous medium containing silver nanoparticles showed a Surface Plasmon Resonance peak at 450 nm. FT-IR analysis reveals that the phenols and amides are mainly responsible for reduction. XRD analysis clearly showed the characteristic Bragg peaks of (111), (200), (220), (311) facets of the face-entered cubic structure of silver nanoparticles and confirmed that these nanoparticles are crystalline in nature.HR-TEM analysis revealed that the green synthesized SNPs were spherical in shape with an average size of 10 nm. The antibacterial effect of synthesized AgNPs on different bacterial strains with the zone of inhibition 14.1 mm on Escherichia coli 12.2 mm on Pseudomonas aeruginosa, 11.3 mm on Staphylococcus aureus and 11.1 mm on Bacillus subtilis respectively. DPPH analysis shows that the nanoparticles possess 67.48 percent of antioxidant activity. The above results also correlated with the other species of Fabaceae such as, Abrus precatorius, Cicer arietinum, Callindra haematocephala Clitoria ternatea, and Pongamia pinnata both in their nanoparticles characteristics and also their antibacterial activity.