Biogenic ZnO Nanoparticles from Allium Cepa and Tagetes erecta: Synthesis, Characterization and its Antidiabetic,...

Plant-based nanoparticles have potential uses and advantages over traditional physico-chemical techniques. In this study, zinc oxide nanoparticles (ZnO-NPs) were biosynthesized from Tagetes erecta flower extract and Allium cepa peel extract, characterized and evaluated their antioxidant, and antidiabetic activities. UV-visible absorption spectroscopy (UV-Vis) revealed a characteristic absorption peak at 355 nm, while X-ray diffraction (XRD) confirmed the presence of crystalline ZnO-NPs having an average size of 35.14 nm. Fourier transform infrared (FTIR) spectroscopy provided evidence for presence of functional groups that stabilizes nanoparticles, elemental composition was confirmed by energy-dispersive X-ray spectroscopy (EDX). Scanning electron microscopy (SEM) provided evidence of the rod-like morphology of nanoparticles, and dynamic light scattering determined the particle size distribution and polydispersity index. The biosynthesized ZnO-NPs presented a range of biological activities that included key antioxidant properties and strong inhibition of α-glucosidase activity (IC₅₀ = 35.9 ± 2.49 µg/mL). The MTT assay was performed for cytotoxicity screening MIN6 pancreatic β-cells that confirmed high viability from 99.4% at 10 µg/mL to 85.6% at 100 µg/mL, indicating non-toxic behaviour. Furthermore, the biosynthesized ZnO-NPs also induce dose-dependent stimulation of insulin secretion, with fold-increases ranging from 2.29 to 7.64 (p ≤ 0.0001) compared to controls. The ZnO-NPs derived from peel of Allium cepa and the floral extracts of Tagetes erecta shown strong antioxidant and antidiabetic characteristics, suggesting that they have the potential to be effective therapeutic agents with minimal side effects for advanced biomedical applications.