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Enzyme Research
Volume 2017, Article ID 5724902, 12 pages
Research Article

Inhibition of α-Amylases by Condensed and Hydrolysable Tannins: Focus on Kinetics and Hypoglycemic Actions

1Postgraduate Program of Food Science, University of Maringá, Avenida Colombo 5790, 87020900 Maringá, PR, Brazil
2Department of Biochemistry, University of Maringá, Maringá, PR, Brazil
3Department of Chemistry, Federal University of Santa Catarina, Florianópolis, SC, Brazil

Correspondence should be addressed to Rosane Marina Peralta; moc.liamg@atlarepmenasor

Received 23 January 2017; Revised 24 March 2017; Accepted 29 March 2017; Published 14 May 2017

Academic Editor: Sunney I. Chan

Copyright © 2017 Camila Gabriel Kato et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of the present study was to compare the in vitro inhibitory effects on the salivary and pancreatic α-amylases and the in vivo hypoglycemic actions of the hydrolysable tannin from Chinese natural gall and the condensed tannin from Acacia mearnsii. The human salivary α-amylase was more strongly inhibited by the hydrolysable than by the condensed tannin, with the concentrations for 50% inhibition (IC50) being 47.0 and 285.4 μM, respectively. The inhibitory capacities of both tannins on the pancreatic α-amylase were also different, with IC50 values being 141.1 μM for the hydrolysable tannin and 248.1 μM for the condensed tannin. The kinetics of the inhibition presented complex patterns in that for both inhibitors more than one molecule can bind simultaneously to either the free enzyme of the substrate-complexed enzyme (parabolic mixed inhibition). Both tannins were able to inhibit the intestinal starch absorption. Inhibition by the hydrolysable tannin was concentration-dependent, with 53% inhibition at the dose of 58.8 μmol/kg and 88% inhibition at the dose of 294 μmol/kg. For the condensed tannin, inhibition was not substantially different for doses between 124.4 μmol/kg (49%) and 620 μmol/kg (57%). It can be concluded that both tannins, but especially the hydrolysable one, could be useful in controlling the postprandial glycemic levels in diabetes.