Effect of Quantity of Plant Extract on Physicochemical Properties and Biomedical Applications of Phytoconstituent-Coated ZnONPs

This study delved into how the quantity of extract (Withania somnifera root) affects the physicochemical properties and biomedical applications of ZnONPs. For this study, three samples of phytoconstituents-coated ZnONPs were prepared by altering the extract volume i.e., 10[Formula: see text]mL, 20[Formula: see text]mL and 30[Formula: see text]mL of 10% (w/v) extract solution (corresponding samples were marked as WS10, WS20 and WS30). UV–Vis spectroscopy preliminary confirms the formation of ZnONPs with surface plasmon resonance (SPR) peaks at 361[Formula: see text]nm, 359[Formula: see text]nm and 356[Formula: see text]nm for WS10, WS20 and WS30 samples, respectively. Fourier transform infrared data confirmed the presence of different functional groups. X-ray diffraction revealed the crystalline nature and high purity of samples. FESEM confirmed spherical-shaped ZnONPs with an average particle size of 72–88 nm. The agar well diffusion assay results indicated that out of three samples, WS30 has maximum antibacterial activity, with inhibition zones of [Formula: see text][Formula: see text]mm (against Escherichia coli) and [Formula: see text][Formula: see text]mm (against Streptococcus mutans). Synthesized samples also exhibited mild antioxidant activity. Additionally, we proposed a radical scavenging mechanism for phytoconstituents-coated ZnONPs. The MTT assay suggests WS30 exhibited excellent anticancer activity with IC[Formula: see text] of [Formula: see text] against human liver cancer cells (HepG2), while comparatively lower toxicity was observed against normal human melanoma cells (HaCaT) with IC[Formula: see text] of [Formula: see text]. This work is novel as it investigates the effects of phytoconstituents amount on the production of ZnONPs as reducing and coating agents that play a critical role in their overall biomedical applications.