Potent α-glucosidase inhibitors purified from the red alga Grateloupia elliptica

Diabetes mellitus is a most serious and chronic disease whose incidence rates are increasing with incidences of obesity and aging of the general population over the world. One therapeutic approach for decreasing postprandial hyperglycemia is to retard absorption of glucose by inhibition of alpha-glucosidase. Two bromophenols, 2,4,6-tribromophenol and 2,4-dibromophenol, were purified from the red alga Grateloupia elliptica. IC50 values of 2,4,6-tribromophenol and 2,4-dibromophenol were 60.3 and 110.4 mu M against Saccharomyces cerevisiae alpha-glucosidase, and 130.3 and 230.3 mu M against Bacillus stearothermophilus alpha-glucosidase, respectively. In addition, both mildly inhibited rat-intestinal sucrase (IC50 of 4.2 and 3.6 mM) and rat-intestinal maltase (IC50 of 5.0 and 4.8 mM). Therefore, bromophenols of G. elliptica have potential as natural nutraceuticals to prevent diabetes mellitus because of their high ot-glucosidase inhibitory activity. (C) 2008 Elsevier Ltd. All rights reserved.