Purple Yam Polyphenol Extracts Exert Anticolitis and Anticolitis-Associated Colorectal Cancer Effects through Inactivation of NF-κB/p65 and STAT3 Signaling Pathways

Abstract

Colorectal cancer is a malignancy with high incidence and mortality worldwide, and ulcerative colitis (UC) is strongly associated with colorectal cancer. Purple yam, also known as <i>Dioscorea alata</i>, has been reported to be rich in plant polyphenols that have possessed anti-inflammatory, antioxidant, and antitumor properties. However, it is not clear whether purple yam polyphenol extracts (PYPE) can improve colitis and inhibit colitis-related colorectal tumorigenesis. Therefore, we used dextran sulfate sodium (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced colitis-associated colorectal cancer (CAC) models in mice to evaluate the preventive value and possible mechanisms of PYPE. It was found that PYPE effectively alleviated DSS-induced colitis, inhibited macrophage infiltration, and reduced the production of the pro-inflammatory cytokines, such as TNF-α, IL-6, IL-1β, IL-17A, CXCL1, and MCP-1, and the higher the concentration of PYPE, the better the inhibitory effect. In addition, PYPE dramatically prevented the development of CAC and tumor proliferation in mice. Furthermore, PYPE inactivated NF-κB and STAT3 signaling to exert anti-inflammatory and anticancer effects. Taken together, these findings indicate that PYPE may be used as a promising preventive strategy against UC and CAC.