Determination of Polysaccharides Content in Zhaotong Gastrodia elsta

The polysaccharides content in 14 samples of Gastrodia elsta produced in Zhaotong and 3 samples of G.elsta bought outside Yunnan Province was determined by means of applying phenol-sulfuric acid method.The absorptiophotometric determinations were carried out at 490 nm.There was a linear relationship between the photometric value and the concentration within the scale of 0-112.0 μg/mL(r=0.997 3).The RSD value of precision test was 0.07%,the RSD value of stability test was 1.67%,and the recovery rate and its RSD value were 100.6%and 1.37% respectively.The results of the study indicated that the determination of polysaccharide contents by phenol-sulfuric acid method was simple but accurate,the polysaccharides content in the G.elsta produced in Xiaocaoba Township of Yiliang County,Zhaotong Prefecture was 10.4%-21.6%,which was generally higher than those produced from other regions.The polysaccharides content might be adopted as one of the indexes to identify the quality of G.elsta produces.