Green synthesis of silver and gold nanoparticles using quercetin extracted from Arctium lappa by HPLC, Characterization and Estimation of antioxidant activity

Arctium lappa is a therapeutic plant high in bioactive components, including flavonoids, which have antioxidant, anti-inflammatory, and antibacterial effects. Quercetin, a major flavonoid, is recognized for its pharmacological properties. The purpose of this study was to extract quercetin from A. lappa and use it for the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs) to evaluate their antioxidant properties. Quercetin was extracted using the Soxhlet method with petroleum ether, chloroform, and methanol. Quercetin was purified using hydrolysis and crystallization before being characterized using HPLC, UV-Vis, FTIR, and NMR methods. Laser ablation was used to synthesize AuNPs and AgNPs, with extracted quercetin acting as a reducing agent. The nanoparticles were examined with SEM, TEM, and XRD. Antioxidant activity was measured using the DPPH free radical scavenging test, and IC50 values were generated to compare to standard ascorbic acid.HPLC indicated that the maximum quantity of quercetin (98.6 %) was achieved using chloroform extraction. AgNPs had a spherical shape via a typical size of 20-40 nm, whereas AuNPs ranged from 80-160 nm. AgNPs had the highest antioxidant capacity (89.59 %), followed by AuNPs (83.32 %) and quercetin (73.22 %). The IC50 values were 100.4 mu g/mL, 120.8 mu g/mL, and 146.36 mu g/mL, respectively.The researchers effectively extracted quercetin from A. lappa and created AuNPs and AgNPs with significant antioxidant characteristics. AgNPs demonstrated superior free radical scavenging activity, indicating their potential use in biomedical applications, notably antioxidant therapy. More research is needed to understand their medicinal potential fully.