Anti-ulcerative Colitis Function Of Bletilla Striata Polysaccharide

The tubers of Bletillla striata had been used as one of the fundamental herb to treat alimentary canal mucosal damage,peptic ulcer,bleeding,bruises and burns in traditional Chinese medicine.Previously,we had investigated the basic function and corresponding ingredients of this herb.As a result,bletillan,one glucomann polysaccharide was isolated and identified.Bletillan showed capacities to treat gastric and bowel ulcers.It could be digested by normal rat's intestinal microflora in vitro.Inflammatory bowel disease(IBD),include ulcerative colitis(UC)and Crohn's disease,was a kind of chronic refractory disease.Taken into account of mucosal damage repair capacity,bletillan had potential clinical advantage in treat IBD,although its function and molecular mechanisms remained unknown.Consequently,the current project planned to evaluate function of bletillan in ulcerative colitis.Bletillan were extracted from Bletilla striata planted in Pu'er city of Yunnan province.In vitro digestion experiments of bletillan by rat's intestinal flora were carried out.The molecular weight(Mw)change of bletillan was detected by HPSEC,and the flora changes of E.coli,lactobacillus and bifidobacteria in intestinal flora were analyzed.The results indicated as follows:(1)under the in vitro digestion of intestinal flora,bletillan lost its molecular weight steadily,and turned to a series of oligosaccharides with average Mw to be 0.851 k Da in the end.(2)bletillan could promote the proliferation of bifidobacterium and lactobacillus(P<0.05),and showed no effect on the proliferation of E.coli.The anti-UC function of bletillan was conducted using acetic acid enema ulcerative colitis modle in rats.Bletillan(25,50,100 mg/kg,p.o.)was applied for 7 days,with methalazine as a positive drug.Index factors,including body weight,disease activity index(DAI),colon coefficient,histological lesion,and selected cytokines in colon tissue were evaluated.The test results showed as follows:(1)bletillan(25,50,100 mg/kg)could restore the weight of rats(P<0.05)and reduce DAI(P<0.05)significantly,and bletillan(50,100 mg/kg)could improve the colon coefficient significantly(P<0.05).(2)The recovery effect of mucosal epidermal cells was observed obviously and dose-dependently after treatment of bletillan(25,50,100 mg/kg),as displayed in the colon pathological slices with intact mucous membrane,continuous integrated epidermis,clear and ordered shapes of glands,with less infiltrated inflammatory cells and no obvious ulcer occurred.(3)The levels of TNF-? and IL-1 ? in the colon tissue was decreased(P<0.05)in bletillan(50,100 mg/kg)groups,and the content of IL-10 was increased(P<0.05)in bletillan(100 mg/kg)group.These results showed that bletillan had certain anti-UC effects,which might be ascribed to the promotion of the recovery of mucosa,regulation of the inflammatory factors such as reduction the levels of TNF-? and IL-1 ?,and up-regulation of IL-10.