Aqueous Cymbopogon citratus Extract Mediated Silver Nanoparticles: Part I. Influence of Synthesis Parameters, Characterization, and Biomedical Studies
Himabindu Kurra, Aditya Velidandi, Mounika Sarvepalli, Ninian Prem Prashanth Pabbathi, Vikram Godishala
Abstract
This study explores the green synthesis of silver nanoparticles (AgNPs) using Cymbopogon citratus (lemongrass) extract as a reducing agent. Synthesis was confirmed by a color change (light yellow to dark brown) under optimal conditions: 1.50 mM silver nitrate, 3.5% v/v extract, at 100 °C, with a pH of 9, and for 60 min. The AgNPs exhibited spherical morphology, a hydrodynamic diameter of 135.41 ± 49.30 nm, a zeta potential of −29.9 ± 1.4 mV, crystalline structure, and minimal aggregation. AgNPs showed significant antibacterial activity, particularly at >20 µg/well, with the zones of inhibition varying by bacterial strain. In vitro studies demonstrated anti-inflammatory, antidiabetic (α-glucosidase and α-amylase inhibition), and antioxidant activities, with AgNPs outperforming plant extract and nearing standard efficacy at higher concentrations. Cyto-toxicity studies indicated that AgNPs and plant extract were less toxic than doxorubicin but exhibited concentration-dependent effects on cancerous and non-cancerous cells. Eco-toxicity assays revealed that AgNPs were less acutely toxic than controls but posed risks with prolonged exposure. This work highlights the eco-friendly synthesis of AgNPs and their potential in biomedical applications, demonstrating efficacy in antibacterial and antioxidant activities.