Witch Hazel-Derived ZnO Nanoparticles: Green Synthesis and Exceptional Multifunctionality in Antibiotic Removal, Inflammation Control, Bacterial Inhibition, and Colorectal/Breast Cancer Suppression

Abstract

In this work, we report a simple, green synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous extract of witch hazel (Hamamelis virginiana) as both reducing and stabilizing agent. The successful formation of crystalline ZnO NPs was confirmed by XRD, UV-Vis, ATR-FTIR, zeta potential, and TEM analyses, revealing highly stable nanoparticles with an average size of 17.3 nm and a bandgap of 3.42 eV. The biosynthesized ZnO NPs were highly effective in removing the antibiotic ceftriaxone from aqueous solution. Adsorption followed the Langmuir isotherm and pseudo-second-order kinetics, achieving a maximum capacity of 154.5 mg/g via a spontaneous, endothermic physisorption process. SEM images showed that the sponge-like morphology of the nanoparticles facilitated drug loading, with particle size increasing noticeably after ceftriaxone adsorption. Both bare ZnO NPs and ceftriaxone-loaded nanoparticles displayed strong antibacterial activity against Escherichia coli and Bacillus subtilis. Moreover, they exhibited promising anticancer properties against human colorectal (Caco-2) and breast (MCF-7) cancer cell lines, with IC₅₀ values of 12.5 µg/mL and 22.4 µg/mL, respectively. These findings demonstrate that witch hazel-mediated ZnO nanoparticles offer an environmentally benign, multifunctional nanoplatform that combines efficient antibiotic removal with potent antibacterial and anticancer effects, making them attractive candidates for biomedical and environmental applications.