20(S)‐ Protopanaxadiol saponins isolated from Panax notoginseng target the binding of HMGB1 to TLR4 against inflammation in experimental ulcerative colitis

Abstract

AbstractUlcerative colitis (UC) has emerged as a global healthcare issue due to high prevalence and unsatisfying therapeutic measures. 20(S)‐ Protopanaxadiol saponins (PDS) from Panax notoginseng with anti‐inflammatory properties is a potential anti‐colitis agent. Herein, we explored the effects and mechanisms of PDS administration on experimental murine UC. Dextran sulfate sodium‐induced murine UC model was employed to investigate anti‐colitis effects of PDS, and associated mechanisms were further verified in HMGB1‐exposed THP‐1 macrophages. Results indicated that PDS administration exerted ameliorative effects against experimental UC. Moreover, PDS administration remarkably downregulated mRNA expressions and productions of related pro‐inflammatory mediators, and reversed elevated expressions of proteins related to NLRP3 inflammasome after colitis induction. Furthermore, administration with PDS also suppressed the expression and translocation of HMGB1, interrupting the downstream TLR4/NF‐κB pathway. In vitro, ginsenoside CK and 20(S)‐protopanaxadiol, the metabolites of PDS, exhibited greater potential in anti‐inflammation, and intervened with the TLR4‐binding domain of HMGB1 predictably. Expectedly, ginsenoside CK and 20(S)‐protopanaxadiol administrations inhibited the activation of TLR4/NF‐κB/NLRP3 inflammasome pathway in HMGB1‐exposed THP‐1 macrophages. Summarily, PDS administration attenuated inflammatory injury in experimental colitis by blocking the binding of HMGB1 to TLR4, majorly attributed to the antagonistic efficacies of ginsenoside CK and 20(S)‐protopanaxadiol.