Plant-mediated ZnO nanoparticles using Allophylus concanicus: Synthesis, characterization, and in vitro biological evaluation

Abstract

This study reports the green synthesis of zinc oxide nanoparticles (ZnONPs) using Allophylus concanicus leaf extract (Ac-ZnONPs) via an eco-friendly co-precipitation method. Nanoparticle formation was confirmed by a color change and a UV-Visible absorption peak at 354​​​​​​ ​nm. FE-SEM revealed spherical nanoparticles averaging 33.14​​​​​​ ​nm, with EDX confirming Zn, O, and C. FTIR indicated phenolic and flavonoid functional groups involved in reduction and capping. PXRD patterns matched the hexagonal wurtzite ZnO phase (ICDD No. 01-070-8072), with calculated lattice parameters a= 3.26 A˚ and c= 5.22​​​​​​ A˚.Zeta potential of -18.4​​​​​​​ mV suggested moderate colloidal stability. Biological evaluations demonstrated strong antibacterial activity (MICs of 1.25 Mu g/mL for Gram-positive and 5 Mu g/mL for Gram-negative bacteria), likely due to ROS generation and membrane disruption. Ac-ZnONPs exhibited excellent antioxidant activity (93.26 percent DPPH scavenging at 200​​​ Mu g/mL) and notable anti-inflammatory activity (IC sub(50) of 15.92 plus-minus 0.56​ Mu g/mL, comparable to diclofenac sodium). Moderate antidiabetic activity was observed (IC sub(50) values of 20.27 plus-minus 0.39 Mu g/mL for alpha-amylase and 18.18 plus-minus 0.39​ Mu g/mL for alpha-glucosidase). These findings highlight the multifunctional bioactivity of Ac-ZnONPs, supporting their potential for diverse biomedical applications and offering a sustainable route for plant-based ZnO nanomaterials.