Facile green synthesis of nano-sized ZnO using leaf extract of Morinda tinctoria: MCF-7 cell cycle arrest, antiproliferation, and apoptosis studies

Zinc oxide nanoparticles (ZnO NPs) were prepared by a facile, one-pot, greener approach using aqueous leaf extract of the medicinal plant Nuna (Morinda tinctoria) and were analyzed by ultraviolet–visible (UV–Vis) and Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. The TEM images confirmed that the as-prepared greener Nuna (Nu)-mediated ZnO NPs (Nu-ZnO NPs) were spherical in shape, with an average diameter of 8–10 nm. Further, the single phase and crystallinity of the Nu-ZnO NPs were observed by PXRD pattern. In addition, the biogenic Nu-ZnO NPs showed high cytotoxicity in human breast adenocarcinoma (MCF-7) cells in vitro. These tiny spherical bodies produced profound toxicity according to the MTT assay, with IC₅₀ of 46 µg/mL. Apoptosis and morphological changes were studied using acridine orange/ethidium bromide and 4′,6-diamidino-2-phenylindole fluorescence staining and MTT assays. Finally, the anticancer efficacy of biosynthesized Nu-ZnO NPs was imparted by dysregulation of cell division through arrest of growth-promoting and inhibiting signals in the S phase, with further reduction in the G2/M phase of the cell cycle. In conclusion, Nu-ZnO NPs conferred MCF-7 cell toxicity by modulating proliferation and inducing apoptosis.