Research Of Colon Biodegradability And Anti-ulcerative Colitis Activity Of Bletilla Striata Polysaccharide

Objectives: In order to prepare a novel flora enzyme triggered oral colon drugdelivery system (OCSDS), the biodegradability and anti-ulcerative colitis activity of selfextracted and purified Bletilla striata polysaccharide (BSP) were evaluated.Methods: Based on eastblish content of BSP was analyzed by HPGPC-ELSDmethod, the degradation test of BSP was performed using paddle method in simulatedgastrointestinal tract fluid according to the pH and additives. Ulcerative colitis (UC)mice were obtained after oral administration of dextran sulfate sodium (DSS). Effects ofBSP concentration and molecular weight on the UC mice were observed such as generalcondition, daily body weight, stools and hematochezia, et al. Disease activity index(DAI) and histological damage index (HI) were assessed after sacrificing the mice on8thday. In addition, the effects of combinations of BSP and curcumin on DSS induced UCmice were also observed using the method described above, too.Results: The results of biodegradability test showed that no obvious degradation ofBSP occurred in different pH solution including pH1.2, pH6.8and pH7.8. Butinterestingly, significant degradation of BSP was determined in artificial colon juicesupplemented with rats colon contents at pH7.8. This result implies the potential of theBSP application in OCDDS triggered by colon flora enzyme. In the bioactivity test, UCmodel mice in high dose and low molecular weight groups of BSP showed relativelylow DAI and HI compared with other experimental groups. The pathological slices ofcolon from UC mice which were oral administrated with high dose of high molecularweight, middle dose of low MW and high dose of crude extract of BSP displayed intactmucous membrane, continuous and integrated epidermis, clear and orderliness glands,less infiltrated inflammatory cells and no obvious ulcer occurred. It means the lowmolecular weight BSP plays more effective roles in the treatment of UC although the mechanism needed to be further clarified. Furthermore, the combination of curcuminand low molecular BSP (high dose) showed more satisfied anti-UC activity from theobservation of DAI, HI and pathological slices of colon from UC mice.Conclusions: The preliminary data of present study demonstrated that lowmolecular weight BSP possessed the characteristics of degradation by colon floraenzyme and anti-ulcerative colitis activity, which indicated the potential of BSP as anovel excipient used for flora enzyme triggered colon specific delivery systems.