Alpha-glucosidase inhibitory activity of bromophenol purified from the red alga Polyopes lancifolia.

A bromophenol, bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, was purified from the red alga Polyopes lancifolia. Its IC(50) values were 0.098 and 0.120 microM against Saccharomyces cerevisiae and Bacillus stearothermophilus alpha-glucosidases, respectively, and 1.00 and 1.20 mM against rat-intestinal sucrase and maltase. This bromophenol competitively inhibited S. cerevisiae alpha-glucosidase with a K(I) value of 0.068 microM and was very stable at pH 2 for 60 min at 37 degrees C. Therefore, this P. lancifolia bromophenol may have potential as natural nutraceutical for the management of type 2 diabetes.