α-Amylase and Lipase Inhibitory Activity and Structural Characterization of Acacia Bark Proanthocyanidins

• Published in: Journal of natural products (Washington, D.C.) Vol. 74; no. 2; pp. 119 - 128
• Main Authors: Kusano, Rie, Ogawa, Sosuke, Matsuo, Yosuke, Tanaka, Takashi, Yazaki, Yoshikazu, Kouno, Isao
• Format: Journal Article
• Language: English
• Published: Northbrook, IL American Chemical Society and American Society of Pharmacognosy 25-02-2011; American Society of Pharmacognosy
• Subjects: Acacia - chemistry; alpha-Amylases - antagonists & inhibitors; Biological and medical sciences; General pharmacology; Lipase - antagonists & inhibitors; Medical sciences; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Pancreas - enzymology; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Bark - chemistry; Proanthocyanidins - chemistry; Proanthocyanidins - isolation & purification; Proanthocyanidins - pharmacology; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Bark; Triacylglycerol lipase; Esterases; Oligomer; Flavonoid; Medicinal plant; Polyphenol; Dicotyledones; Angiospermae; Proanthocyanidin; α-Amylase; Catechin; Enzyme; Pharmacognosy; Enzyme inhibitor; Acacia mearnsii; In vitro; Biological activity; Carboxylic ester hydrolases; Glycosylases; Leguminosae; Glycosidases; Plant origin; Hydrolases; Isolation; Spermatophyta; Structural analysis
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np100372t

The bark extract of Acacia mearnsii showed strong lipase and α-amylase inhibition activities. Fractionation of the extract by column chromatography and subsequent 13C 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).