Genotoxic and carcinogenic risks associated with the consumption of repeatedly boiled sunflower oil

Repeated boiling of vegetable oils at high temperature in cooking and frying is a very common practice and leads to the formation of a class of toxic substances. Among them, polycyclic aromatic hydrocarbons (PAHs) are well-documented for their mutagenic/carcinogenic potential. The objectives of the present study were to evaluate the genotoxic and carcinogenic risks associated with the consumption of repeatedly boiled sunflower oil, which is one of the commonly consumed vegetable oils in southeast Asian countries. The presence of PAHs was analyzed using high-performance liquid chromatography (HPLC) methods in fresh, single-boiled, and repeatedly-boiled sunflower oil (FSO, SBSO, and RBSO) samples. A higher amount of known carcinogenic/mutagenic PAHs in RBSO samples were shown, as compared to FSO and SBSO. Oral administration of RBSO in Wistar rats resulted in significant induction of aberrant cells (p < 0.05) and micronuclei (p < 0.05) incidence in a dose-dependent manner. Oxidative stress analysis also showed a significant decrease in levels of antioxidant enzymes, such as superoxide dismutase and catalase, with a concurrent increase in reactive oxygen species and lipid peroxidation in animals following RBSO consumption, as compared to FSO or SBSO (p < 0.05). Additionally, RBSO administration alone and along with diethylnitrosamine for 12 weeks induced altered hepatic foci, as noticed by the alteration in positive (γ-glutamyl transpeptidase and glutathione-S-transferase) and negative (adenosine-triphosphatase, alkaline phosphatase, and glucose-6-phosphatase) liver biomarkers. A significant decrease in the relative and absolute hepatic weight in RBSO-supplemented rats was also noted (p < 0.05).