Plant-extract mediated green approach for the synthesis of ZnONPs: Characterization and evaluation of cytotoxic, antimicrobial and antioxidant potentials

Plant-extract-mediated green synthesis of nanoparticles is significantly attracting the attention of scientific community due to its simple, cost-effective, energy-efficient and eco-friendly nature. The present study focuses on the biological synthesis of zinc oxide nanoparticles (ZnONPs) using aqueous solution of Rhamnus virgata as both reducing and stabilizing agents. The formation, morphology, structure and other physicochemical properties of ZnONPs were extensively studied using different microscopic and spectroscopic techniques. Scherer equation deduced a mean crystallite size of similar to 20 nm for ZnONPs. Detailed in vitro biological activities revealed significant therapeutic potentials. Strong antibacterial and antifungal activities were reported for ZnONPs. Dose-dependent cytotoxicity assays revealed against Leishmania tropica promastigotes (IC50 : 8.34 mu g/mL), amastigotes (IC50 : 13.6 mu g/mL), HepG2 cancer cell line (IC50 : 19.67 mu g/mL), brine shrimps (IC50 : 26.34 mu g/mL). Significant antioxidant activities and enzyme inhibition assays were performed. The biocompatibility assays with RBCs and macrophages confirmed the bio-safe nature of biogenic ZnONPs. In conclusion, ZnONPs have shown potential biological applications and should be subjected to further in vivo studies on toxicity in animal models to develop its nano-pharmacological relevance in biomedical applications. (C) 2019 Elsevier B.V. All rights reserved.