title: Characterization of proanthocyanidins in stems of Polygonum multiflorum Thunb as strong starch hydrolase inhibitors.
abstract: Characterization of polyphenolic compounds in the stems of P. multiflorum was conducted using HPLC, high resolution LC-MS and LC-MSn. Proanthocyanidins in particular were isolated in 4.8% yield using solvent extraction followed by Sephadex LH-20 fractionation. HPLC analysis using a diol column revealed oligomers (from dimer to nonamer) as minor components, with (epi)catechin monomeric units predominating, and oligomers with higher degree of polymerization being dominant. Thiolysis treatment of the proanthocyanidins using mercaptoacetic acid produced thioether derivatives of (epi)catechin as the major product and a mean value of the degree of polymerization of 32.6 was estimated from the ratio of terminal and extension units of the (epi)catechin. The isolated proanthocyanidins were shown to strongly inhibit α-amylase with an acarbose equivalence (AE) value of 1,954.7 µmol AE/g and inhibit α-glucosidase with an AE value of 211.1 µmol AE/g.
authors: Food Science and Technology Program, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors: Hongyu
authors: H
authors: Wang
authors: Lixia
authors: L
authors: Song
authors: Shengbao
authors: S
authors: Feng
authors: Yuancai
authors: Y
authors: Liu
authors: Gang
authors: G
authors: Zuo
authors: Fuli
authors: F
authors: Lai
authors: Guangyuan
authors: G
authors: He
authors: Mingjie
authors: M
authors: Chen
authors: Dejian
authors: D
authors: Huang
mesh_terms: D000880:Anthraquinones / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000032:analysis; D006867:Hydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007700:Kinetics; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry*; D028502:Polygonum / Q000737:chemistry*; D059808:Polyphenols / Q000302:isolation & purification / Q000494:pharmacology; D044945:Proanthocyanidins / Q000032:analysis*; D020005:Propanols / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization; D013213:Starch / Q000378:metabolism*; D013267:Stilbenes / Q000032:analysis; D013438:Sulfhydryl Compounds / Q000737:chemistry; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000880:Anthraquinones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D044945:Proanthocyanidins; D020005:Propanols; D013267:Stilbenes; D013438:Sulfhydryl Compounds; C439395:1-phenylpropanol; C404987:flavan-3-ol; D013213:Starch; D006867:Hydrolases; D000516:alpha-Amylases