本文以蛹虫草子实体为原料，通过建立a-葡萄糖苷酶抑制剂体外验证模型，以麦芽糖作为反应底物，阿卡波糖作为阳性对照，利用体外酶促反应方法，对通过水提、脱色、醇沉、除蛋白及色谱柱纯化得到的不同纯度的蛹虫草多糖的α-葡萄糖苷酶抑制活性进行了验证。结果表明，通过逐步的酶促反应实验，确定蛹虫草中对α-葡萄糖苷酶活性具有较显著抑制作用的功能成分为多糖，并且随着多糖纯度的不断提高其抑制率随之提高。通过对经色谱层析柱纯化后蛹虫草多糖进一步的酶促反应实验研究，表明蛹虫草多糖对α-葡萄糖苷酶的抑制率随多糖浓度的提高而提高，说明蛹虫草多糖的抑制效应存在一定的剂量依赖性，纯化后的多糖对α-葡萄糖苷酶的半数抑制浓度（IC50）为4.22 mg/mL，呈现出良好的降血糖功能，为今后将蛹虫草开发为降血糖药物及保健品提供了一定的理论依据。

In this study, the fruiting body of Cordyceps militaris was used to validate its α-glucosidase inhibitory activity in vitro. Using maltose as the reaction substrate and acarbose as a positive control, in vitro enzymatic reactions were carried out to validate the α-glucosidase inhibitory activity of polysaccharides (with different purities) from Cordyceps militaris, which were purified by water extraction, decolorization, alcohol precipitation, deproteinization, and column chromatography. The results of stepwise enzymatic reaction showed that the functional component with α-glucosidase inhibitory activity in Cordyceps militaris was polysaccharide, and the inhibitory rate gradually increased with increasing purity of the polysaccharide. The results of further enzymatic reactions using Cordyceps militaris polysaccharide purified by column chromatography showed that the rate of α- glucosidase inhibition increased with increasing concentration of polysaccharide, which was demonstrated that the inhibitory activity of Cordyceps militaris polysaccharide was dose-dependent within a certain concentration range. The half-maximal inhibitory concentration (IC50) value of purified polysaccharide was 4.22 mg/mL, showing a good hypoglycemic function. This study provides a theoretical basis for the future development of hypoglycemic drugs and health products using Cordyceps.

国家农业科技成果转化资金项目（2011GB2A100009）；天津市高等学校科技发展基金计划项目（20090604），天津科技大学科学研究基金资助项目（20120106）