title: Inhibition of alpha-glucosidase and alpha-amylase by flavonoids.
abstract: The inhibitory activity of six groups of flavonoids against yeast and rat small intestinal alpha-glucosidases and porcine pancreatic alpha-amylase was compared, and chemical structures of flavonoids responsible for the inhibitory activity were evaluated. Yeast alpha-glucosidase was potently inhibited by the anthocyanidin, isoflavone and flavonol groups with the IC50 values less than 15 microM. The following structures enhanced the inhibitory activity: the unsaturated C ring, 3-OH, 4-CO, the linkage of the B ring at the 3 position, and the hydroxyl substitution on the B ring. Rat small intestinal alpha-glucosidase was weakly inhibited by many flavonoids, and slightly by the anthocyanidin and isoflavone groups. 3-OH and the hydroxyl substitution on the B ring increased the inhibitory activity. In porcine pancreatic alpha-amylase, luteolin, myricetin and quercetin were potent inhibitors with the IC50 values less than 500 microM. The 2,3-double bond, 5-OH, the linkage of the B ring at the 3 position, and the hydroxyl substitution on the B ring enhanced the inhibitory activity, while 3-OH reduced it.
authors.affiliation: Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Tadera
authors.forename: Yuji
authors.initials: Y
authors.lastname: Minami
authors.forename: Kouta
authors.initials: K
authors.lastname: Takamatsu
authors.forename: Tomoko
authors.initials: T
authors.lastname: Matsuoka
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D065089:Glycoside Hydrolase Inhibitors; D007421:Intestine, Small / Q000201:enzymology; D007700:Kinetics; D015394:Molecular Structure; D010179:Pancreas / Q000201:enzymology; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013552:Swine; D000516:alpha-Amylases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D065089:Glycoside Hydrolase Inhibitors; D000516:alpha-Amylases; D000520:alpha-Glucosidases