Icariside I Inhibits Tumor Growth by Regulating Gut Microbiota

Recent studies showed that a favorable gut microbiome is associated with enhancedsystemic and antitumor immunity by modulating responses to antibody immunotherapyin melanoma patients. In this study, we found that icariside I, a novel anti-cancer agentisolated from Herbal Epimedium , significantly inhibited B16F10 melanoma growth invivo through regulation of gut microbiota and host immune. Oral administration oficariside I improved the altered gut microbiota community with marked restoration ofLactobacillus spp. and Bifidobacterium spp. abundance in feces of tumor-bearingmice. We also found that icariside I is capable to improve the levels of microbiotaderivedmetabolites such as short-chain fatty acids (SCFAs) and indole derivatives,consequently repairing intestinal barrier and systemic inflammation of tumor-bearingmice. Icariside I exhibited strong immunological anti-tumor activity, directly manifestedby up-regulation of multiple lymphocyte subsets including CD4+ and CD8+ T cells orNK and NKT cells in peripheral blood of tumor-bearing mice.