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Rejitha, L.R.*
Department of Botany, Mar Ivanios College, Nalanchira, Thiruvananthapuram-695015, India
Email: rejitha.lr@mic.ac.in
Received-27.07.2026, Revised-10.08.2026, Accepted-29.08.2026
Abstract: The increasing prevalence of antimicrobial resistance has necessitated the exploration of novel therapeutic agents from natural sources. This study investigates the green synthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Thuja occidentalis L. and evaluates their antimicrobial potential against pathogenic bacteria and fungi. The biosynthesis of AgNPs was confirmed by UV-Visible spectroscopy, revealing a characteristic surface plasmon resonance peak at 420 nm, with the rapid formation of stable nanoparticles observed within 20 minutes of reaction. The antibacterial activity, assessed using the agar well diffusion method, demonstrated significant concentration-dependent inhibition against Pseudomonas aeruginosa, with maximum zones of inhibition of 16 mm at 60 µg concentration, comparable to the standard antibiotic streptomycin (18 mm). However, Staphylococcus aureus exhibited resistance to all tested concentrations, indicating differential susceptibility between Gram-negative and Gram-positive bacteria. Antifungal evaluation revealed selective activity against Candida albicans with a zone of inhibition of 16 mm, while Aspergillus niger and Phytophthora capsici showed resistance. The study successfully demonstrates a simple, rapid, cost-effective, and environmentally friendly approach for synthesizing antimicrobial silver nanoparticles using T. occidentalis leaf extract. These findings validate the traditional medicinal use of Thuja and suggest its potential as a sustainable source for developing alternative antimicrobial agents. The green nanotechnology approach presented herein offers promising applications in biomedical fields, contributing to the global effort to combat antimicrobial resistance while promoting environmental sustainability.
Keywords:Thujaoccidentalis, Silver nanoparticles, Green synthesis, Antimicrobial activity, UV-Vis spectroscopy
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