Structural Characterization And Hypoglycemic Activity Of A Polysaccharide Isolated From The Fruit Of Physalis Alkekengi L.

Physalis alkekengi L. of the family of Solanaceae is a traditional Chinese herbal plant distributed abundantly in the northeast region of China. It has been reported to have many ethnopharmacological properties including anti-inflammatory, anti-cold, anti-cough and anti-fungal activities. Some active components from P. alkekengi, such as physalin, alkaloids, and flavone, have been investigated. However, no specific studies on polysaccharides isolated from P. alkekengi fruit have been carried out.In this papar: a water-soluble polysaccharide isolated with hot water from the mature fruits of Physalis alkekengi L., after frozen, trawed and removed protain the crude polysaccharide was fractionated with different concentration of ethanol and purified by Sepharose CL-6B gel filtration chromatography. The structural characterization and hypoglycemic activity of the purified polysaccharide fraction (designated PPSB) were evaluated in this paper. PPSB (Mw= 27kDa) is an acid heteropolysaccharide consisting of Ara, Gal, Glc and GalA in ratio of 2.6:3.6:2:1 andα-configuration. It has a backbone composed of (1→5)-linked Ara, (1→6)-linked Gal with 3 branches attached to O-3 of (1→6)-linked Gal and terminated with either Gal or Gal and Glc, and all of Glc and the majority of GalA are distributed in branches. Pharmaceutical experiments showed PPSB administered orally in alloxan-induced diabetic mice can significantly reduce blood glucose levels and water intake, and increase the body weight of diabetic mice compared with alloxan-induced diabetic control group. The results suggest PPSB could be considered as a potential candidate for developing a new anti-diabetic agent.