Colorectal cancer (CRC) as the third largest malignant tumor in the world has seriously threatened human health. Polysaccharides hold significant potential for application in the treatment and prevention of CRC. This study aims to compare the anti-CRC activity of Lignosus rhinocerotis polysaccharide (LRP) and degraded LRP (DLRP), and elucidate the mechanism of their anti-CRC effects. Results showed that the anti-CRC effect of DLRP (IC50, 55.44 µg/mL) was superior to that of LRP (IC50, 220.92µg/mL). LRP and DLRP can cause cycle arrest in HT-29 cells at the G2/M phase, and simultaneously promote the accumulation of ROS in cells, thereby leading to cell apoptosis. Moreover, the mitogen-activated protein kinase signaling pathway was involved in apoptosis and cell cycle arrest in HT-29 cells. In vivo experiment revealed that DLRP effectively ameliorated clinicopathologic symptoms of CRC mice and attenuated inflammatory responses, and also increased concentrations of acetic, propionic, and butyric acid in feces. Apart from significantly inhibiting the growth of harmful bacteria such as Helicobacter and Mucispirillum, DLRP also promoted the proliferation of beneficial bacteria such as Parabacteroides, Muribaculum, and Akkermansia. Overall, DLRP is expected to be a potential drug for the treatment of CRC.

Tea represents an abundant source of naturally occurring polyphenols. Tea polyphenols (TPs) have received growing attentions for its wide consumption in the world, and more importantly its pleiotropic bioeffects for human health. After ingestion, TPs may undergo absorption and phase II reaction in the small intestine, and most undigested proportion would be submitted to the colon to interact with gut microbiota. Interactions between gut microbiota and TPs are bidirectional, including not only bacteria-mediated TPs metabolism, e.g., removal of gallic acid moiety and ring fission to release phenolic acid catabolites, but also TPs-based modification of bacterial profiles. Crosstalk between TPs and gut microbes may benefit for gut barrier function, for example, improvement of the intestinal permeability to alleviate inflammation. Moreover, by reshaping microbial composition and associated metabolites, TPs may exert a systemic protection on host metabolism, which contributes to improve certain chronic metabolic disorders. Given that, further understanding of the metabolic fate of TPs and interplay with gut microbiota as well as potential health-promoting effects are of great significance to development and application of tea and their polyphenolic components in the future as dietary supplements and/or functional ingredients in medical foods.