Ethanol Fractionation Precipitation of Polysaccharides from Bletilla striata
Background Polysaccharides from Bletilla striata (BSP) is the main active ingredients in Bletilla striata tuber, and belongs to glucomannans with average molecular weight of 10~20 KD.BSP has function of a stringency and hemostasis.Because of its better biocompatibility, BSP was studied and applied as drug carriers in novel DDSs in the past decade.But extraction and purification method of BSP from the crude herbs was still not fully investigated, which limited the applications of BSP as excipients or active agents in pharmaceutical industry.Objective To provide BSP with reliable quality for further study, ethanol precipitation method was used to fractionate polysaccharide from crude BSP, and BSP fractions with different molecular weight (MW) was obtained and evaluated.Methods (1) Crude BSP was extracted by water extraction and alcohol precipitation method, and then fractioned by ethanol precipitation method.The content of BSP was determined by phenol-sulphuric acid method on UV-Vis spectrometer.(2) BSP were successively fractionated by gradient concentrations of ethanol (30%, 40%, 50% and 70%) into four fractions, named as BSP-1, BSP-2, BSP-3 and BSP-4 respectively.And then BSP fractions were characterized by UV and IR spectrometry.(3) The solution viscosity of BSP fractions were tested by Ubbelohde viscometer with water as solvent, and the extrapolation method was adopted to calculate the relative MW of each BSP fractions.Results (1) The polysaccharide content of obtained crude polysaccharide from Bletilla striata is 67.61%, and the yield is 65.73%.(2) As ethanol concentration increasing from 30% up to 70%, the yield of the obtained BSP precipitation was progressively decreased, whereas the polysaccharide content increased gradually.UV spectrum showed no absorption peaks of nucleic acids at 260 nm, but there was one absorption peak of protein at 280 nm.Both UV and IR spectrum indicated that there was almost no difference on chemical structure from BSP-1 to BSP-4.(3) The average MW of obtained BSP fraction was lower when higher ethanol concentration was used.But due to partial solubility and impurity of BSP-1, there is no way to calculate the effective MW data.Conclusions The Ethanol Precipitation method provide a simple but rapid technique for purification and fractionation of polysaccharide from Bletilla striata.
Ethanol fractionation precipitation Bletilla striata Polysaccharides Viscosity-average molecular weight
HONG Tongtong HAN Xin ZHANG Xia WANG Wenping
Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan 750004;Ningxia Engineering & Technology Research Center For Modernization of Hui Medicine, Yinchuan 750004;Ningxia Research Institute of Medicine & Pharmacy, Yinchuan 750004
国内会议
2013年中国药物制剂大会——中国药学会药剂专业委员会2013年学术年会暨国际控释协会中国分会2013年学术年会
武汉
英文
393-394
2013-10-26（万方平台首次上网日期，不代表论文的发表时间）