Green synthesis of metallic nanoparticles has emerged as a sustainable and eco-friendly alternative to conventional chemical and physical methods, utilizing biological entities such as plant extracts, bacteria, fungi, and algae as reducing and stabilizing agents. This biogenic approach not only minimizes the use of toxic chemicals but also imparts unique physicochemical properties to the nanoparticles, enhancing their biomedical potential. Among various applications, the anticancer activity of green-synthesized metallic nanoparticles, particularly those of silver, gold, zinc oxide, and copper, has gained significant attention. Their biocompatibility and targeted action make them promising candidates for cancer therapy with reduced side effects compared to conventional chemotherapeutics. Herein, we display the results of our recent research studies where we unveiled the anti- cancer mechanisms of newly green synthesized gold and silver metallic nanoparticles on oral squamous cell carcinoma cell lines. Our studies also examined the safety of these nanoparticles on normal cells. Additionally, we present briefly the main concerns of green synthesis and the reported assumptions to overcome these shortcomings in order to put green synthesized metallic nanoparticles into practical use as potential next-generation cancer therapeutics.

The main objectives are to clarify the advantage of green synthesized metallic nanoparticles as anticancer agents, to explain the main anti- cancer mechanisms of these nanoparticles in oral cancer cell lines and their effect on normal cells based on our previous research in addition to displaying the main limitations of green synthesis and how to overcome them.