Oolong tea polyphenols affect the inflammatory response to improve cognitive function by regulating gut microbiota

[Display omitted] •OTP restored the gut microbiota dysbiosis induced by circadian rhythm disorder.•OTP reduced inflammation response and strengthened tight junction proteins to ameliorate intestinal barrier dysfunction.•OTP alleviated neuronal damage in the hippocampus and reduce cognitive impairment. Oolong tea polyphenols (OTP) has received increasing attention for their ability to reduce cognitive dysfunction by modulating the gut microbiota and related metabolites. In our study, the circadian rhythm disorder (CRD) mice showed gut microbial disruption and cognitive impairments. OTP treatment restored the gut microbiota disruption including up-regulated the relative abundance of Akkermansia and Muribaculum, and down-regulated Desulfovibrio. Moreover, OTP reduced inflammation response, decreased lipopolysaccharide (LPS) levels, and strengthened tight junction proteins (TJPs) to ameliorate intestinal barrier dysfunction. These changes inhibited the elevated levels of pro-inflammatory factors, therefore, attenuated neuronal damage and Aβ protein aggregation in the hippocampus. Additionally, OTP supplementation also regulated the levels of metabolites related to cognitive function, some of them closely associated with microbiota. Our findings speculate that OTP potentially modulates cognitive impairment and inflammation caused by circadian disruption by modulating the gut microbiota.