Green synthesis and characterization of silver nanoparticles from Hydrocotyle umbellata L. and its antibacterial properties

Abstract

The present study demonstrates the green synthesis of silver nanoparticles (AgNPs) using Hydrocotyle umbellata L. leaf extract, an eco-friendly and sustainable approach. The formation of AgNPs was confirmed by a visible color change from light green to light brown, indicating the reduction of silver ions (Ag⁺) to metallic silver nanoparticles (Ag⁰). The synthesized nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS). FTIR analysis identified key functional groups (C=C, N-O, C-H, C-N, and aromatic compounds) involved in the reduction and stabilization of AgNPs. XRD confirmed the crystalline nature of the nanoparticles, revealing a face-centered cubic (FCC) structure. SEM-EDS analysis showed uniform, spherical nanoparticles with high elemental purity. The biosynthesized AgNPs exhibited significant antibacterial activity against both Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Klebsiella pneumoniae) bacteria, with dose-dependent inhibition zones. These findings highlight the potential of H. umbellata-mediated AgNPs as an effective, eco-friendly antimicrobial agent for biomedical applications.