Biogenic synthesis of zinc oxide nanoparticles using leaf extract of Oxalis stricta and its effect on colon cancer: an in vitro and in silico approach

Abstract

Colon cancer is among the most common colorectal malignancies and a leading cause of cancer-related mortality worldwide. Conventional therapies, including chemotherapy, often cause severe side effects and drug resistance, underscoring the need for safer and more effective alternatives. Green nanotechnology has emerged as a promising approach in cancer therapy, offering sustainable and biocompatible therapeutic options. In this study, Zinc oxide nanoparticles (ZnO NPs) were synthesized using Oxalis stricta leaf extract via an eco-friendly green synthesis approach and evaluated for their anticancer potential against colon cancer. Characterization by UV-VIS spectroscopy, Dynamic Light Scattering, Scanning Electron Microscopy, Fourier-transform Infrared spectroscopy, and X-ray Photoelectron Spectroscopy confirmed the nanoscale size, stability, and surface functionalization of the ZnO NPs. Cytotoxicity evaluation using the MTT assay revealed a dose-dependent anti-proliferative effect on colon cancer cells, with an IC₅₀ value of 30.27 µg/mL. Hemolysis assay indicated good biocompatibility with minimal red blood cell lysis. Apoptosis induction was evidenced by fluorescence staining techniques, including DAPI, AO/EB, DCF-DA, and Rhodamine 123, revealing nuclear condensation, oxidative stress, and mitochondrial membrane disruption. In silico molecular docking demonstrated strong binding interactions between phytoconstituents of Oxalis stricta and cancer-related targets MMP-9, GSK3β, and Bcr-Abl. Furthermore, ZnO NPs inhibited cell migration and matrix metalloproteinase activity, as evidenced by wound healing and gelatin zymography assays. These findings suggest that Oxalis stricta mediated ZnO NPs hold significant promise as a biocompatible, multi-targeted nanotherapeutic agent for colon cancer treatment.