Frankincense oil nanoemulsion induces selective cytotoxicity and over ROS-mediated oxidative stress and apoptotic DNA damage in Hep-G2 hepatic cancer cells

Frankincense oil nanoemulsion (FONE) exhibits high bioavailability, enhanced cellular uptake, and improved kinetic stability, making it a promising candidate for therapeutic applications. However, its potential effects on hepatocellular carcinoma (HCC) remain insufficiently explored. This study consequently investigated the cytotoxic and apoptotic activities of FONE on human hepatocellular carcinoma (Hep-G2) cells, focusing on cell viability, oxidative stress, DNA damage, and the regulation of apoptosis-related genes. Cell viability and proliferation were evaluated in Hep-G2 hepatic cancer cells and normal human skin fibroblasts (HSF) using the Sulforhodamine B (SRB) assay. Oxidative stress markers, DNA damage, and apoptotic gene expression were assessed through biochemical analysis, alkaline comet assay, and quantitative real-time PCR (qRT-PCR), respectively. Intracellular reactive oxygen species (ROS) levels were measured using 2,7-dichlorofluorescin diacetate (2,7-DCFH-DA) staining. Treatment with FONE at concentrations of 0.1, 1, 10, 100, and 1000 µg/ml for 48 h caused a significant, concentration-dependent reduction in Hep-G2 cell viability, with a half-maximal inhibitory concentration (IC50) of 176.14 µg/ml, while showing minimal cytotoxicity in HSF cells (IC50 = 515.7 µg/ml). Mechanistic investigations revealed that exposure to FONE IC50 concentration (176.14 µg/ml) significantly elevated ROS level, DNA damage, and lipid peroxidation (malondialdehyde level), accompanied by a marked decline in antioxidant defenses, including glutathione content and glutathione peroxidase activity. Gene expression analysis showed notable upregulation of pro-apoptotic genes p53 and Bax, alongside a strong downregulation of the anti-apoptotic gene Bcl-2, in a concentration-dependent manner. FONE exerts selective cytotoxic effects against Hep-G2 cells, mediated by ROS-induced oxidative stress, DNA damage, and apoptosis induction. These findings highlight FONE's potential as a targeted therapeutic agent for hepatocellular carcinoma. Further in vivo investigations and clinical evaluations are recommended to validate its efficacy and safety.