Evaluation of ZnO nanoparticles biosynthesized from Camellia sinensis leaves: Anticancer effects on HepG2 cells, antioxidant activity, and anti‑hemolytic properties

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and represents a major global health burden due to its high incidence, limited treatment options, and negative impact on patient quality of life. This study aimed to evaluate the anticancer potential of green‑synthesized zinc oxide nanoparticles (ZnO NPs) as a natural alternative therapeutic strategy against HCC. ZnO NPs were biosynthesized using Camellia sinensis leaf extract. The cytotoxic activity of ZnO NPs against human hepatocellular carcinoma cells (HepG2) was assessed using the MTT assay following 72 hours of treatment. Antioxidant activity was determined using the DPPH free radical scavenging assay. Hemocompatibility was evaluated using an erythrocyte hemolysis assay, while genotoxic effects were examined using a DNA fragmentation assay. ZnO NPs exhibited a significant, concentration‑dependent cytotoxic effect on HepG2 cells. Cell viability decreased to 42.13% at 0.5 μg/mL and 26.84% at 5 μg/mL after 72 hours of exposure. The IC50 value was calculated as 2.87 μg/mL, indicating strong antiproliferative activity at low concentrations. Antioxidant analysis revealed enhanced free radical scavenging activity with increasing ZnO NP concentrations, reaching a maximum of 81.63% at 1 μg/mL and a minimum of 63.73% at 0.12 μg/mL. Hemolysis levels remained below detectable limits at all tested concentrations (0.12-1 μg/mL), demonstrating excellent hemocompatibility. Moreover, ZnO NPs did not induce DNA fragmentation, confirming the preservation of DNA integrity. The findings of this study demonstrate that ZnO NPs possess significant anticancer activity at low concentrations while exhibiting excellent hemocompatibility and no detectable DNA damage in vitro.