This study investigated the functions and regulatory mechanism of Portulacae Herba and its chemical components on the Toll-like receptor 4(TLR4)/myeloid differentiation primary response 88(MyD88)/nuclear factor kappa B(NF-κB) inflammatory signaling pathway in the colon tissue of mice with dextran sodium sulfate(DSS)-induced ulcerative colitis(UC). A total of 35 mice were randomly divided into groups, including a blank group, a model group, a mesalazine group(0. 5 g·kg~(-1)), and low, medium,and high dose alkaloids from Portulacae Herba groups(9, 18, 36 mg·kg~(-1)), and a combination treatment group, with 5 mice in each group. The blank group was given purified water, while the other groups were continuously given a 3% DSS solution for 7 days to induce the UC model. From day 8 onwards, the treatment group received oral gavage according to the prescribed doses for 14 days. The overall condition, body weight, stool characteristics, and presence of blood in the stool were recorded daily. After the experiment, the disease activity index(DAI) was assessed for each group, and colon length was measured. Histopathological changes in colon tissue were examined using hematoxylin-eosin(HE) staining. The levels of pro-inflammatory cytokines, tumor necrosis factor-α(TNF-α),and interleukin-1β( IL-1β) in serum were measured by enzyme-linked immunosorbent assay( ELISA). The protein and m RNA expression of TLR4, MyD88, and NF-κB in colon tissue were measured using Western blot and quantitative real-time PCR(qPCR).Compared to the blank group, the model group showed a significant decrease in body weight, a notable increase in DAI scores, a significant shortening of colon length, and evident histopathological damage. The levels of inflammatory cytokines TNF-α and IL-1β in the serum were significantly elevated, and the protein and m RNA expression of TLR4, MyD88, and NF-κB in colon tissue were significantly up-regulated. In contrast, the alkaloids from Portulacae Herba treatment groups significantly improved symptoms and reduced body weight loss in mice, decreased DAI scores, alleviated colon shortening, lowered serum levels of TNF-α and IL-1β,significantly down-regulated the expression levels of TLR4, MyD88, and NF-κB proteins and genes in colon tissue, as well as reduced histopathological damage. Therefore, the study suggests that alkaloids from Portulacae Herba can alleviate intestinal inflammation damage in DSS-induced UC mice, with its mechanism involving the TLR4/MyD88/NF-κB signaling pathway.
