Polysaccharides from tubers of Bletilla striata: Physicochemical characterization, formulation of buccoadhesive wafers and preliminary study on treating oral ulcer.

The purpose of this research is to arouse people's cognition of the dual role of Bletilla striata polysaccharide (BSP)-a kind of biocompatible, biodegradable natural biological materials with myriad pharmacological activities. BSP was extracted and characterized firstly. The results indicated that BSP was composed of mannose and glucose. The backbone of BSP mainly consisted of (1 → 4)-linked β-D-mannopyranose. Afterwards, A 32 factorial design was employed for optimization of lyophilized wafers for the treatment of traumatic oral ulcer with concentrations of BSP and glycerin as independent variables. Tensile strength, mucoadhesive strength, and swelling index were measured as response variables. It was determined that the wafer prepared from a solution containing 4% (w/v) BSP and 7% (w/v) glycerin was the optimal formulation. The wafers exhibited sufficient mechanical strength and suitable surface pH. Morphology of the wafers was observed. DSC/TGA thermograms showed the presence of three peaks weight loss events and decomposition patterns. Moreover, in vivo examinations indicated that the BSP wafer significantly promoted ulcer healing at 7 days, while no statistically significant difference was observed on day 12. In conclusion, this study suggests that BSP is an ideal biomaterial for mucosal adhesion agents, playing a nontrivial role in promoting oral ulcer healing.