Diosgenin-functionalized zinc oxide nanoparticles produced using Hibiscus tiliaceus leaf extract: evaluation of anticancer and antibacterial activities

Diosgenin is a potentially safer treatment for breast cancer. ZnO nanoparticles (ZnO NPs) can overcome their limited water solubility. This study was undertaken to prepare and characterize ZnO NPs and ZnO NP@dios (ZnO NPs loaded with diosgenin), to examine their cytotoxicity against MCF-7 (breast cancer cells), and to test their antimicrobial activity against Escherichia coli and Staphylococcus aureus . The research began with the phyto-production of ZnO NPs using Hibiscus tiliaceus leaf extract media, followed by the preparation of ZnO NP@dios. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and UV–Vis diffuse reflectance spectroscopy (DRS) were performed for the characterization of the nanoparticles. The cytotoxic response induced by ZnO NPs and ZnO NP@dios was analyzed using the 3-(4,5-dimethyl-diazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The agar well diffusion method was utilized to assess antibacterial activity. The ZnO NPs were highly pure and revealed hexagonal and rod-shaped appearances, with nanoscale sizes (45–125 nm). FTIR analysis confirmed the successful preparation of ZnO NP@dios, as evidenced by the distinct absorption band at 1570 cm⁻¹, while TEM images revealed a thin coating layer surrounding the ZnO NPs. Cytotoxicity assays against MCF-7 cells showed dose-dependent inhibition, with diosgenin-functionalized composites demonstrating greater potency. ZnO NPs MA @dios (ZnO NPs derived from H. tiliaceus methanol extract, with zinc acetate precursor and loaded with diosgenin) exhibited the most substantial effect (reducing its IC₅₀ from 48.2 to 37.2 µg/mL). Similarly, diosgenin loading improved the activity of ZnO NPs 1:1 N (ZnO NPs derived from H. tiliaceus water:ethanol 1:1 (v/v) extract, zinc nitrate precursor), reducing its IC₅₀ from 98.8 to 46.7 µg/mL. The inhibition zones against E. coli were 13, 14, 16, 14, 12, and 11 mm for ZnO NPs MA (ZnO NPs derived from H. tiliaceus methanol extract, zinc acetate precursor), ZnO NP MA @dios, ZnO NPs 1:1 N , ZnO NP 1:1N @dios (ZnO NPs derived from H. tiliaceus water: ethanol of 1:1 (v/v) extract, zinc nitrate precursor and loaded with diosgenin), ZnO com (commercial ZnO), and ZnO com @dios (commercial ZnO loaded with diosgenin), respectively. In the case of S. aureus , no inhibition zone was observed. These findings highlight that diosgenin-functionalized ZnO NPs can enhance anticancer efficacy. All types of ZnO NPs and ZnO NP@dios have potential as antibacterial agents against E. coli, but were ineffective against S. aureus .