Biogenic synthesis and physicochemical characterization of metal nanoparticles based on Calotropis procera as promising sustainable materials against skin cancer

The UAE harbors a rich diversity of wild medicinal plants, such as Calotropis procera (CP), that are renowned for their extensive use in traditional medicine due to their abundance of bioactive phytochemicals. Zinc and iron metals possess significant pharmacological effects including antioxidant and anticancer properties. In this study, nanoparticles (NPs) containing zinc and iron were green synthesized utilizing ethanolic and aqueous extracts of CP aerial parts. UV-Vis spectra revealed absorption peaks around 270-275 nm, while FT-IR analysis confirmed successful coating of the NPs with plant's phytochemicals. SEM/EDX analysis indicated a more potent reducing effect of the aqueous extract, whereas the alcoholic extract demonstrated more effective coating of the NPs. DLS showed monodispersed NPs with average sizes of 32.67-202 nm. The alcoholic extract-based zinc and iron NPs exhibited the highest phenolic and flavonoid contents (51.06 ± 2.82 µg of GAE/mg of DW and 66.26 ± 1.12 µg of Qu/mg of DW, respectively) and the strongest antioxidant effect against ABTS and DPPH radicals (IC₅₀ = 52.81 and 148.46 µg/mL, respectively). The aqueous extract-based zinc NPs demonstrated the greatest cytotoxicity against A-431 cell lines (IC₅₀ = 188.97 µg/mL). The findings highlight promising potential of these sustainable materials for therapeutic applications, indicating a need for continued research and development in this area.