Polysaccharide extracted from Portulacae Oleracea L. exerts protective effects against dextran sulfate sodium-induced colitis through inhibition of NF-κB.

Portulacae Oleracea L. (POL) is a traditional Chinese medicine and also an edible vegetable used to treat diarrhea in china for thousands years. Though the therapeutic effect has been proved in clinical trials, the concrete effective component and mechanisms remained elusive. Polysaccharide from POL has been extracted previously and the experiment suggested that POLP could diminish the weight loss and improve the health conditions of mice with DSS induced colitis. Hematoxylin & eosin staining revealed that POLP could improve the histopathological structure of the colon tissue. For the notably variation curve of TNF-α in control, colitis and treatment group, NF-κB was enrolled to investigate the molecular mechanisms of the protective effect of POLP. The protein expression level of NF-κBp65 in cytoplasm increased after POLP treatment of the induced colitis. However, the protein level of NF-κBp65 in the nucleus decreased after administration of POLP. The expression levels of IκBα and NF-κB related proteins Bcl-2 and survivin were also detected and the results suggested that POLP could inhibit the degradation of IκBα and decrease the protein levels of Bcl-2 and Survivin in colitis. It was concluded that POLP could improve the health condition of mice with DSS induced colitis and the mechanisms were closely related with NF-κB via inhibiting the degradation of IκBα.