Biosynthesis of silver nano particles of herbal plant extracts and characterisation by using UV and FTIR analysis

Abstract

The present study explores the green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of Zingiber officinale (ginger rhizome), Carica papaya (papaya seeds), and Camellia sinensis (green tea leaves). Extracts were subjected to phytochemical screening, total phenolic content (TPC) estimation, and characterization of AgNPs by UV–Vis and FTIR. Their biological efficacy was evaluated through catalytic degradation of methylene blue, antioxidant activity (DPPH assay), and antimicrobial studies. Ginger showed the highest TPC (75.65 mg GAE/mg), efficient AgNP formation, and strong antioxidant, antimicrobial, and catalytic activities. Papaya seeds, with lower TPC (13.7 mg GAE/mg), produced AgNPs with moderate antioxidant and antimicrobial effects, particularly against E. coli. Green tea (36.64 mg GAE/mg) yielded stable AgNPs with significant antioxidant, catalytic, and antibacterial activity. These findings highlight plant-mediated AgNPs as eco-friendly nanomaterials with biomedical and environmental potential, with ginger demonstrating the strongest overall performance.