title: Pu-erh tea polysaccharides decrease blood sugar by inhibition of α-glucosidase activity in vitro and in mice.
abstract: Type 2 diabetes is mainly induced by environmental factors such as being overweight, decreased physical activity and inbalanced energy metabolism, such as pancreatic beta-cell dysfunction and peripheral insulin resistance. Acarbose, a microbial carbohydrate and an alpha-glucosidase inhibitor, is currently a useful agent for attenuating type 2 diabetes. However, it is usually accompanied by many side effects, such as abdominal distention, flatulence, diarrhea and meteorism. These side effects may be caused by its strong inhibition of alpha-amylase, leading to the accumulation of several undigested carbohydrates. The bacteria residing in the colon can further ferment the undigested carbohydrate to release gas. Finding a new alpha-glucosidase inhibitor with a low inhibitory effect on alpha-amylase is highly anticipated. In this report we describe a group of carbohydrates found in pu-erh tea polysaccharide (PTPS) that can inhibit alpha-glucosidase but have less of an inhibitory effect on alpha-amylase. The preliminary experiments on mice indicate that PTPS might be better than acarbose at suppressing blood glucose after oral administration of a carbohydrate diet; it is recommended that further clinical trials are required in type 2 diabetes in future studies.
authors.affiliation: Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan. jklin@csmu.edu.tw.
authors.forename: Yea-Tyz
authors.initials: YT
authors.lastname: Deng
authors.forename: Shoei-Yn
authors.initials: SY
authors.lastname: Lin-Shiau
authors.forename: Lie-Fen
authors.initials: LF
authors.lastname: Shyur
authors.forename: Jen-Kun
authors.initials: JK
authors.lastname: Lin
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D028241:Camellia sinensis / Q000737:chemistry*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism; D015536:Down-Regulation; D065089:Glycoside Hydrolase Inhibitors / Q000008:administration & dosage* / Q000737:chemistry; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000737:chemistry; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D011134:Polysaccharides / Q000008:administration & dosage* / Q000737:chemistry; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D011134:Polysaccharides; D000520:alpha-Glucosidases