Green Synthesis, Characterization, and Biomedical Applications of Copper and Copper Oxide Nanoparticles of Plant Origin

The green synthesis approach using plants for the formation of metal/metal oxide nanoparticles is biologically safe and environment-friendly as compared to various physical and chemical methods. Various phytoconstituents present in the plants, such as phenols, flavonoids, alkaloids, tannins, and proteins, act as potential bioresources for the formation of metal/metal oxide nanoparticles. The most common metals/metal oxides used are silver (Ag), copper (Cu), zinc, iron, and gold. Amongst them, copper is a comparably cheap metal than gold and silver. Copper oxide nanoparticles have diverse applications in various fields of therapeutics. This review provides insights regarding the bio-mediated synthesis of copper/copper oxide nanoparticles, factors affecting the synthesis, their characterization, and the biomedical applications, mainly the antibacterial, antifungal, and anticancer activity. Although many trials and research have already been conducted, indicating the potential for developing copper and copper oxide nanoparticles as a future drug, still, more research is needed focusing on different ways to minimize their toxicity and improve biological efficacy.