Ginger and turmeric lipid-solubles attenuate heated oil-induced oxidative stress in the brain via the upregulation of NRF2 and improve cognitive function in rats.

In this study, we elucidated the modulatory potentials of lipid-solubles from ginger and turmeric that may migrate to oils during
heating on the brain antioxidant defense and cognitive response in rats. Male Wistar rats were fed with control diet [including
native canola oil (N-CNO), and native sunflower oil (N-SFO)], or experimental diets [including heated canola oil (H-CNO),
heated sunflower oil (H-SFO), heated canola oil with ginger (H-CNO + GI), heated canola oil with turmeric (H-CNO + TU),
heated sunflower oil with ginger (H-SFO + GI), heated sunflower oil with turmeric (H-SFO + TU)] for 90 days. Memory
parameters [Morris water maze, elevated plus maze, novel object recognition test, T-maze (spontaneous alteration)], locomotor
skills (open field test and rotarod test), antioxidant defense enzymes, reactive oxygen species, NOS2, ICAM-1, and NRF-2 level
in the brain were assessed. Compared to their respective controls, heated oil-fed rats, but not those fed oils heated with ginger or
turmeric, showed significant (p < 0.05) reduction in the memory, motor coordination skills, antioxidant defense enzymes, and
NRF-2 activation in the brain. Compared to their respective controls, the brain NOS-2 and ICAM-1 were significantly (p < 0.05)
increased in heated oil-fed rats, but not those fed oils heated with ginger or turmeric. Chronic intake of repeatedly heated oil
causes brain dysfunction by inducing oxidative stress through NRF-2 downregulation. Lipid-solubles from ginger and turmeric
that may migrate to oil during heating prevent the oxidative stress and cognitive dysfunction triggered by heated oils in rats.