GREEN SYNTHESIS, ANTIBACTERIAL SCREENING AND ANTIOXIDANT ACTIVITY OF SILVER NANOPARTICLES (AGNPS) CAPPED WITH METABOLITES FROM ANDROGRAPHIS PANICULATA (BURM.F.) WALL. EX NEES LEAVES

The study presents a novel method for synthesizing silver nanoparticles (AgNPs) using A. paniculata leaves extract as a bioreducing agent for Ag+ ions derived from AgNO3. The biomolecules within the extract are credited with the reduction process. Characterization techniques including UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD) analysis, and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) analysis were employed to analyze the properties of the synthesized nanoparticles. UV-Vis spectroscopy revealed a prominent Surface Plasmon Resonance (SPR) peak at 550 nm, indicative of the presence of AgNPs with efficient light absorption and scattering properties. SEM analysis provided insights into the morphology and size distribution of the nanoparticles. XRD analysis confirmed the crystalline nature of the nanoparticles, while EDX analysis corroborated the presence of elemental silver in the nanoparticle composition. The antimicrobial activity of the synthesized AgNPs against a spectrum of human pathogens, particularly noteworthy inhibition against E. coli and S. aureus, highlights their potential as antimicrobial agents. Furthermore, the antioxidant activity assessed through the DPPH scavenging assay underscores the potential health benefits of these nanoparticles. A notable observation was the variation in activity between A. paniculata extract and A. paniculata-AgNPs, with the latter exhibiting reduced inhibitory effects attributed to fewer functional groups on the nanoparticle surface. This finding contributes to a deeper understanding of structure-function relationships in nanoparticle-based applications.