Protective Effects of Deinoxanthin on Brain Oxidative Damage and Gut Microbiota in the D-Galactose-Induced Aging Mice

Deinoxanthin (DX), a special hydroxylated tetraterpenoid synthesized by Deinococcus radiodurans, exhibits robust antioxidative activities in vitro and in vivo. The accumulation of excessive reactive oxygen species (ROS) and free radicals in the body would induce brain oxidative damage, thereby contributing to the process of aging. Whether the administration of DX could protect the brain against oxidative damage in aging is of great interest. In this study, we explored the potential beneficial effects of DX on D-galactose (D-gal)-induced aging mice in vivo, particularly its protective effects on the brain against oxidative damage, and its impact on the gut microbiota of aging mice. We demonstrated that treatment with a low dose (25 mg/kg/day) and a middle dose (50 mg/kg/day) of DX could effectively alleviate motor deficits, reduce the hippocampal pathological changes, suppress microglia and astrocyte activation, and attenuate oxidative stress in D-gal-induced aging mice. However, the treatment with a high dose of DX (100 mg/kg/day) seemed to exacerbate these changes, indicating that excessive DX may exacerbate oxidative damage in aging mice. Furthermore, the administration of appropriate DX could restore the gut microbiota in aging mice, while the high dose of DX further aggravated the disturbance of the gut microbiota in aging mice. Collectively, we conclude that taking DX appropriately may be beneficial in preventing oxidative damage to the brain and improving the gut microbiota in aging mice.