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 490nm. There was a linear relationship between the photometric value and the concentration within the scale of 0-112.0μg/mL (r=0.9973). 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.