Ameliorative effect of α-tocopherol and curcumin against the deleterious effects of hydrogenated (thermally oxidized) rice bran oil in rats

Rice bran oil (RBO) is known for its health benefits due to its high content of natural antioxidants like tocotrienols, tocopherols, and oryzanols, which combat oxidative stress and inflammation. However, repeated heating of RBO above 110°C leads to degradation, forming harmful oxidative components and reducing its antioxidant content. This study aimed to investigate the effects of long-term consumption of thermally oxidized RBO on rats and the potential protective effects of curcumin and α-tocopherol supplementation. RBO was subjected to oxidative degradation through repeated frying cycles at temperatures ranging from 100°C to 180°C for 45 days. Physicochemical and phytochemical parameters of the oxidized RBO were analyzed. In vivo experiments evaluated serum biochemical, hematological, and histopathological parameters, along with oxidative and inflammatory responses in rats fed with oxidized RBO for 45 days. Results showed that thermal oxidation at 180°C significantly altered the chemical composition of RBO, increasing oxidative markers and reducing nutritional components. Consumption of oxidized RBO led to decreased body weight gain, elevated levels of various biochemical markers indicating liver and kidney dysfunction, hyperlipidemia, and increased oxidative and inflammatory damage in rats. However, supplementation with curcumin and α-tocopherol effectively mitigated these harmful effects. In conclusion, long-term consumption of thermally oxidized RBO negatively affects health parameters in rats, but fortification with curcumin and α-tocopherol helps alleviate these adverse effects