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Six new C 21 steroidal glycosides ( 1 – 6 ) and one dideoxysaccharide ( 7 ), named atratcynosides A–F and atratcynose A, were isolated from the 80% ethanol extract of the root of Cynanchum atratum , together with three known compounds ( 8 – 10 ). The structures of the new compounds were determined on the basis of extensive spectral analyses and qualitative chemical methods. All compounds were subjected to detect the immunosuppressive activities by an in vitro model of concanavalin A-induced proliferation of T-lymphocytes from mice. Compounds 1 – 3 showed significant immunosuppressive activities in dose-dependent manners with the IC 50 values from 3.3 to 7.0 μM. Moreover, the structure–activity relationship of the steroidal glycosides on the immunosuppression was analyzed. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD) is caused by aberrant immune responses to the gut microbiota. Among the gut microbiota, adherent-invasive Escherichia Coli (AIEC) is thought to be the pathogen through invading the intestinal epithelial cells and causing inflammation. IL-17 secretion increase, induced by enhanced bacterial adhesion to the intestine epithelium, could on one hand protect the mucosa, but on the other hand, over amount of IL-17 initializes inflammation reactions that in turn damages the mucosa. The relationship between IL-17 and AIEC is still unclear. In this study, we tried to elucidate the function of IL-17 in AIEC-mediated colitis. Wild type (WT) and IL-17 knockout (IL-17 KO) mice were inoculated with AIEC strain E. coli LF82 and treated with dextran sodium sulphate (DSS). Histological examination of the colon was performed. Mucosa damage was assessed and scored. IL-22 and IL-17 in colon tissues were detected by ELISA, qPCR and immunohistochemistry methods. Transient AIEC colonization in IL-17 KO mice resulted in increased intestinal epithelial damage, systemic bacterial burden and mortality compared with WT controls. Moreover, IL-17 is required for the induction of IL-22 in the experimental animal models during AIEC strain E. coli LF82 colonization. These results indicate IL-17 plays a protective role in AIEC strain E. coli LF82 induced colitis by promoting IL-22 secretion. [ABSTRACT FROM AUTHOR]