title: Effects of soluble tea polysaccharides on hyperglycemia in alloxan-diabetic mice.
abstract: The effects of tea water extracts (TWE), crude tea polysaccharides (CTP), and a tea polysaccharide fraction (TPF) were tested on hyperglycemic diabetic mice. Results indicated that TWE, CTP, and TPF could significantly decrease fasting blood glucose (FBG) and glucosylated serum protein (GSP) in alloxan-induced diabetic mice compared to the control group. In vitro antioxidant activities of TWE, CTP, and TPF for scavenging hydroxyl radicals and superoxide radicals decreased with the degree of purification and were lowest for TPF. High-performance gel permeation chromatography (HPGPC) and component analysis revealed the molecular mass distribution and constituents of TWE, CTP, and TPF, indicating that a 100-120 kDa fraction contained the hypoglycemic activity. This fraction was essentially composed of polysaccharides (approximately 90%) with substantial amounts of arabinogalactan proteins. The second-derivative IR spectra of TWE, CTP, and TPF with peak intensity around 1075 and 1045 cm(-1), which characterize galactopyranose in the backbone and arabinofuranose units in side branches, respectively, further substantiated the importance of the arabinogalactan proteins. Taken together, the results indicate that a soluble tea polysaccharide is the major hypoglycemic factor in tea and that this polysaccharide may be developed to a potential natural hypoglycemic functional ingredient.
authors.affiliation: College of Food Science and Engineering and College of Life Science and Technology, Ocean University of China, Qingdao 266003, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhou
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Wang
authors.forename: Pingnan
authors.initials: P
authors.lastname: Sun
authors.forename: Peter
authors.initials: P
authors.lastname: Bucheli
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Yangfeng
authors.initials: Y
authors.lastname: Hou
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001786:Blood Glucose / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D011134:Polysaccharides / Q000494:pharmacology / Q000627:therapeutic use*; D012995:Solubility; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D011134:Polysaccharides; D013662:Tea