A novel neutral exopolysaccharide (EPS-III) was isolated from culture broth of Cordyceps militaris (C. militaris). The EPS-III was a homogeneous polysaccharide with Mw of 1.56 x 10(3) kDa. The yield of EPS-III from culture broth was 123.2 +/- 3.1 mg/L and the sugar content was 93.32 +/- 0.87%. The backbone of EPS-III was mainly consisted of –>4)-alpha-D-Galp-(1–>, while –>3, 6)-alpha-D-Manp-(1–>, –>4)-alpha-D-Manp-(1–>, –>3)-beta-D-Galp-(1–> and –>3)-alpha-D-Glcp-(1–> were distributed in the backbone or in the branch chains. The EPS-III had helix structure when dissolved in weak alkaline solution. It also had branched and intertwined form on the surface. The inhibition of alpha-glucosidase significantly increased as the increase of purity of exopolysaccharides. The EPS-III had effective inhibition on the alpha-glucosidase with dose-effect relationship. Besides, the results of hypoglycemic activity analysis in vivo indicated that EPS-III can alleviate weight loss, reduce plasma glucose concentration, improve glucose tolerance, protect immune organs and repair dyslipidemia to relieve diabetes in STZ-induced diabetic mice. The manuscript first studied the hypoglycemic activity of exopolysaccharide of by C. militaris, proving and promoting the application value of culture broth. The structure characterization of EPS-III laid experimental foundations on the exploration of structure-activity relationship.
Sun, H., Yu, X., Li, T., & Zhu, Z. (2020). Structure and hypoglycemic activity of a novel exopolysaccharide of Cordyceps militaris. Int J Biol Macromol. doi:10.1016/j.ijbiomac.2020.10.207