Green Synthesis of Zinc Oxide Nanoparticles: Pharmacological Potential and Mechanistic Insights

Introduction: Nanotechnology has revolutionized various sectors, particularly in biomedical sciences and drug delivery. Among metal oxide nanoparticles, Zinc Oxide Nanoparticles (ZnO NPs) have emerged as a multifunctional agent due to their well-documented antibacterial, anticancer, anti-inflammatory, and antioxidant activities. However, the conventional synthesis of ZnO NPs often involves hazardous reagents, high energy input, and the generation of toxic byproducts, posing risks to both human health and the environment. These challenges necessitate the development of eco-friendly alternatives, such as green synthesis methods employing biological sources. Methods: This review analyzes recent studies on the green synthesis of ZnO NPs using biological sources such as plant extracts, bacteria, and fungi. The pharmacological activities of these biogenically synthesized ZnO NPs were evaluated through in vitro and in vivo experiments, focusing on antibacterial, anticancer, and antioxidant effects. Mechanisms of action were also explored. Results: Green synthesis methods effectively produced ZnO NPs with improved biocompatibility and therapeutic efficacy. Biological entities influenced nanoparticle size, shape, and stability. Antibacterial activity was attributed to membrane disruption and the induction of oxidative stress. Anticancer effects were observed via ROS generation and mitochondrial dysfunction, leading to apoptosis. Antioxidant properties were linked to free radical scavenging capabilities. Discussion: The review highlights the potential of green synthesis as a sustainable and eco-friendly approach to producing pharmacologically active ZnO NPs. Biological agents not only simplify synthesis but also enhance the therapeutic potential of the nanoparticles. Conclusion: Green-synthesized ZnO NPs offer promising biomedical applications due to their enhanced biocompatibility and multifunctional activity. Despite their potential, challenges such as synthesis variability, toxicity concerns, and scalability must be addressed through further toxicological evaluations and clinical studies.