Green synthesis of ZnO nanoparticles from the leaves of Passiflora foetida L. and its antimicrobial and cytotoxic activities.

The present study demonstrates the eco-friendly green synthesis of zinc oxide nanoparticles using Passiflora foetida L., an ethnomedicinal plant traditionally employed by sacred grove-centric communities of Uttar and Dakshin Dinajpur, West Bengal, for treating enteric disorders. The biogenic synthesis involved zinc nitrate as a precursor and aqueous leaf extract as a natural reducing and stabilizing agent. The obtained nanoparticles were characterized by UV-Vis spectroscopy, FESEM, EDX, FTIR, DLS, and zeta potential analysis, confirming their crystalline nature, spherical morphology (~ 99.42 nm), and purity. The functional groups identified through FTIR suggested phytochemical-mediated stabilization. The nanoparticles exhibited potent antioxidant activity, particularly in DPPH and ABTS assays, demonstrating efficient radical scavenging with low IC50 values. Antibacterial evaluation revealed broad-spectrum efficacy against both Gram-positive and Gram-negative bacteria, with E. coli and S. typhimurium showing the highest sensitivity. Minimum inhibitory concentration (MIC) analysis confirmed dose-dependent inhibition. Cytotoxicity assessment using the WRL-68 human liver cell line indicated moderate toxicity only at higher concentrations (IC50= 471.05 µg/mL), suggesting good biocompatibility. Overall, the study highlights the potential of P. foetida-mediated ZnO- nanoparticles as promising antimicrobial and antioxidant agents, integrating traditional ethnomedicinal knowledge with green nanotechnology to combat antibiotic-resistant pathogens and oxidative stress.