Comparable neuroprotection efficacy of raw Pu-erh tea and ripened Pu-erh tea in D-galactose-induced aging mice via gut-brain axis

Prevention of age-related cognitive decline by tea consumption is of great interest. This study systematically compared the neuroprotective efficacy of raw Pu-erh tea (RPT) and ripened Pu-erh tea (FPT) against D-galactose-induced aging in mice, focusing on the modulation of the gut-brain axis. To enhance translational relevance, mice were provided with ad libitum access to RPT or FPT infusions, mimicking human drinking habits. Results showed that both RPT and FPT significantly ameliorated cognitive impairment and hippocampal damage in aging mice, with comparable efficacy despite their distinct phytochemical profiles. Both teas reversed gut microbiota dysbiosis, consistently enriching core taxa such as Lachnospiraceae_NK4A136_group and Alistipes, and restored host sphingolipid metabolism, leading to reduced cerebral ceramide levels and Aβ deposition. Notably, the key difference lay in polyphenol components: RPF acted mainly via native monomeric catechins, whereas FPT relied on fermentation-derived polymers (theaflavins, thearubigins, theabrownins) and gallic acid. Despite fundamental compositional differences imposed by pile fermentation, both teas provided similar protection against age-related cognitive decline, primarily through the gut microbiota-sphingolipid-brain axis. Our findings highlight that both RPT and FPT represent effective dietary interventions for cognitive health, with the choice being a matter of preference.