Screening of the optimized prescription from Suqingwan in terms of its therapeutic effect on DSS-induced ulcerative colitis by its regulation of inflammatory and oxidative mediators

Abstract Ethnopharmacological relevance Suqingwan (SQW), a traditional Chinese medicine used for treating ulcerative colitis (UC), is composed of 13 kinds of Traditional Chinese medicines (TCMs). According to TCM theory, we investigated whether a simplified prescription composed of the herbs with some functions, would have similar effects to SQW and examined its potential treatment mechanism of action. Materials and methods We categorized the herbs in SQW into four groups according to their traditional functions and used an orthogonal experimental design to obtain nine separated prescriptions (SPs) of SQW. A dextran sulfate sodium (DSS)-induced UC mouse model was used to evaluate the anti-ulcer colitis effects of the nine SPs and the calculated prescription (CP) was obtained based on the orthogonal t values of the disease activity index (DAI) of the nine SPs. The effect of the CP and SP8 were verified in the DSS-induced UC model, and the DAI and histopathology of the UC mice were examined. Myeloperoxidase (MPO), malondialdehyde (MDA), tumor necrosis factor (TNF)-α, interleukin (IL)−1β, IL-6, IL-4 and IL-10 of the mice in SP8 were investigated to explore the mechanism of action of the optimized prescription with regard to anti-inflammatory and anti-oxidation effects. Results Among the 9 SPs, separate prescription 6, 7 and 8 (SP6, SP7 and SP8) and the SQW formulation all significantly reduced the DAI of the UC mice and, in particular, SP8 had an effect similar to SQW, which consists of Sanguisorba officinalis L., Rehmannia glutinosa Libosch. and four other herbal medicines. In a further investigation, SP8 was found to improve the ulcerative colitis in mice in terms of both clinical symptoms and histopathology. The mortality of mice in the SP8 group was 33.3%, better than CP based on the orthogonal t values (83.3%). SP8 could also reduce the levels of TNF-α, IL-1β, IL-6, MPO and MDA and increase the levels of IL-4 and IL-10 in colon tissue of UC mice in comparison with those of the model group ( p Conclusions An optimized prescription (SP8) from SQW was obtained based on an orthogonal experimental design, which involved 6 herbal medicines, with significantly fewer herbs than in the original prescription. SP8 displayed a similar anti-ulcerative colitis activity to SQW, and its in vivo mechanism of action is related to up-regulation of anti-inflammatory cytokines and down-regulation of pro-inflammatory and oxidative factors.