ABSTRACT
Gut microbiota dysbiosis is a risk factor for colorectal cancer (CRC) in inflammatory bowel disease (IBD). In this study, the effects of Panax notoginseng saponins (PNS) on colitis-associated CRC progression were evaluated on an azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model. In vivo, PNS significantly relieved AOM/DSS-induced colon tumorigenesis and development by reducing the disease activity index (DAI) scores and colon tumor load. The 16S rRNA data of fecal samples showed that the microbiome community was obviously destructed, while PNS could recover the richness and diversity of gut microbiota. Especially, PNS could increase the abundance of Akkermansia spp. which was significantly decreased in model group and negatively correlated with the progression of CRC. Moreover, ginsenoside compound K (GC-K) was evaluated on the effects of human CRC cells, which was the main bio-transformed metabolite of PNS by gut microbiota. Our data showed that PNS played important role in the prevention of the progression of CRC, due to their regulation on the microbiome balance and microbial bio-converted product with anti-CRC activity.
ABSTRACT
Panax notoginseng saponins (PNS) are the major components of Panax notoginseng, with multiple pharmacological activities but poor oral bioavailability. PNS could be metabolized by gut microbiota in vitro, while the exact role of gut microbiota of PNS metabolism in vivo remains poorly understood. In this study, pseudo germ-free rat models were constructed by using broad-spectrum antibiotics to validate the gut microbiota-mediated transformation of PNS in vivo. Moreover, a high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was developed for quantitative analysis of four metabolites of PNS, including ginsenoside F1 (GF1), ginsenoside Rh2 (GRh2), ginsenoside compound K (GCK) and protopanaxatriol (PPT). The results showed that the four metabolites could be detected in the control rat plasma, while they could not be determined in pseudo germ-free rat plasma. The results implied that PNS could not be biotransformed effectively when gut microbiota was disrupted. In conclusion, gut microbiota plays an important role in biotransformation of PNS into metabolites in vivo.