Azadirachta indica leaves mediated green synthesis of metal oxide nanoparticles: A review

Various attempts have been made for green synthesis of metal oxide nanoparticles; revealing the significance of plant extracts in reducing metal sources to nanoparticles and applications in various scientific domains. Azadirachta indica (Neem) is an evergreen tree, belonging to the family Meliaceae. Its leaves are reported to contain several phytochemicals like flavonoids, glycosides, terpenes, and triterpenes. This article focuses on applications of Azadirachta indica leaves extract in the fabrication of nanoparticles of various metal oxides like calcium oxide, chromic oxide, cobalt oxide, cupric oxide, iron oxide, manganese oxide, molybdate oxide, titanium dioxide, zinc oxide. In respective research attempts, these metal oxide nanoparticles were evaluated for one or more applications like antibacterial, anti-cancer activity, photocatalytic activity. The use of the aqueous extract of neem leaves indicated the involvement of its polar phytocompounds in reducing the metal oxides and stabilizing their nanoparticles. In conclusion, it could be noted that metal oxide nanoparticles have better antimicrobial activity and photocatalytic potential over aqueous leaves extract.