Synergistic effect of combined treatment with baicalin and emodin on DSS‐induced colitis in mouse

The treatment of combination drugs in complex diseases has been spotlighted. Ulcerative colitis (UC) is a chronic inflammatory disease that has made progress in combination therapy. Baicalin, a flavone from Scutellaria baicalensis Georgi. (Lamiaceae), and emodin, an anthraquinone derivative from Rhei Radix et Rhizoma. (Polygonaceae), both have been reported to possess antiinflammatory activities. Our study investigated whether combined treatment with baicalin and emodin had a synergistic effect in inhibiting colitis inflammation. The results showed that baicalin combined with emodin at a lower dose had the same effect as the two drugs alone significantly alleviated the symptoms of dextran sulfate sodium (DSS)-induced colitis mice, involving the prevention of the loss of body weight and colon shortening, the decrease in the disease activity index (DAI), and intestinal damages. The combined treatment decreased the expression of CD14/TLR4/NF-κB pathway proteins and increased the expression of PPAR-γ protein in the colon of colitis mice. Further study in vitro has shown that baicalin decreased the expression of CD14, whereas emodin increased the expression of PPAR-γ, both of which inhibited the activity of NF-κB and exerted antiinflammatory effects. Furthermore, compared to the treatment using the two drugs individually, baicalin combined with emodin had more significant effects on the expression of CD14 and PPAR-γ. Therefore, emodin combined with baicalin had a synergistic effect on DSS-induced colitis.