title: α-Amylase and lipase inhibitory activity and structural characterization of acacia bark proanthocyanidins.
abstract: The bark extract of Acacia mearnsii showed strong lipase and α-amylase inhibition activities. Fractionation of the extract by column chromatography and subsequent (13)C NMR and MALDI-TOF-MS analysis revealed that the active substances are proanthocyanidin oligomers mainly composed of 5-deoxyflavan-3-ol units. In addition, 4'-O-methylrobinetinidol 3'-O-β-D-glucopyranoside, fisetinidol-(4α,6)-gallocatechin, and epirobinetinidol-(4β,8)-catechin were isolated as new compounds, and their structures were determined from spectroscopic data. Furthermore, a modified thiol degradation method using strongly acidic conditions was applied to the extract to yield three thiol degradation products derived from robinetinidol units. This method is useful for characterizing acacia proanthocyanidins (wattle tannins).
authors.affiliation: Laboratory of Natural Product Chemistry, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-Machi, Nagasaki 852-8521, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Kusano
authors.forename: Sosuke
authors.initials: S
authors.lastname: Ogawa
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Yazaki
authors.forename: Isao
authors.initials: I
authors.lastname: Kouno
mesh_terms: D000045:Acacia / Q000737:chemistry*; D008049:Lipase / Q000037:antagonists & inhibitors*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010179:Pancreas / Q000201:enzymology; D024301:Plant Bark / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
chemical_list: D044945:Proanthocyanidins; D008049:Lipase; D000516:alpha-Amylases