Dracocephalum moldavica L. extract alleviates experimental colitis in rats by modulating gut microbiome and inflammatory pathways.

Several studies have revealed that an imbalance of the intestinal microbiota is involved in intestinal inflammation associated with ulcerative colitis (UC). Therefore, regulating the homeostasis of gut microbiota is critical for treating UC. Dracocephalum moldavica L. (DML) extract, a common traditional Chinese medicine, has been demonstrated to possess numerous pharmacological effects, such as antioxidative, anti­inflammatory, and antibacterial properties. The aim of the present study was to evaluate the beneficial effects of DML extract and the probable mechanism of action in a dextran sulfate sodium­induced chronic colitis model. It was found that DML extract ameliorated UC by improving disease activity index, weight loss, colon length, and histological scoring. DML extract administration also enhanced the count of Lactobacillus and reduced the count of Romboutsia. Furthermore, the results of network pharmacology analysis revealed that the active ingredients (including luteolin, rosmarinic acid, oleanolic acid, ursolic acid, apigenin, acacetin, kaempferol, and isorhamnetin) in the DML extract were closely associated with anti­inflammatory activity via various signaling pathways, including the NF­κB, IL­17, TNF, and Toll­like receptor (TLR) signaling pathways. Western blot analysis further indicated that DML extract downregulated the expression of members of the TLR4/NF­κB signaling pathway, which was associated with colitis. Thus, it was hypothesized that DML extract exerted its anti­colitis effects by modulating the gut microbiota and inflammatory pathways.