Oligoepicatechins from the leaves of machilus konishii
Journal
Journal of the Chinese Chemical Society
Journal Volume
61
Journal Issue
5
Pages
589-593
Date Issued
2014
Author(s)
Abstract
Epicatechin (3) and five oligomers (2, 4, 5, 10, 11) together with five other type compounds were isolated and characterized from n-BuOH and EtOAc soluble fractions of the ethanol extract of the leaves of Machilus konishii Hayata. Their structures were elucidated by means of MS and NMR spectroscopic analyses. Dehydrodiepicatechin A (11) is the first occurrence as a natural product although it has been prepared from epicatechin. The stereochemistry of 11 is elucidated for the first time on the basis of 1D NOESY and chemical model analyses. Tiliroside (7) and kaempferol 3-O-α-L-(2a,4a-di-E-p-coumaroyl)- rhamnopyranoside (8) showed moderate inhibitory activity against α-glucosidase. Following the bioassay-guided fractionation, 11 compounds including five oligoepicatechins were isolated from the leaves of M. konishii. Dehydrodiepicatechin A (11) represents the first occurrence of such a natural product and its stereochemistry was elucidated for the first time. Two of the isolated compounds showed moderate anti-α-glucosidase activity Copyright © 2014 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Type
journal article