Two unsaturated fatty acids with potent α-glucosidase inhibitory activity purified from the body wall of sea cucumber (Stichopus japonicus).

UNLABELLED: One therapeutic approach for preventing diabetes mellitus and obesity is to retard the absorption of glucose via inhibition of α-glucosidase. Two unsaturated fatty acids with strong α-glucosidase inhibitory activity, 7(Z)-octadecenoic acid (1) and 7(Z),10(Z)-octadecadienoic acid (2), were purified from the body wall of Stichopus japonicus. IC(50) values of compounds 1 and 2 were 0.51 and 0.67 μg/mL against Saccharomyces cerevisiae α-glucosidase and 0.49 and 0.60 μg/mL against Bacillus stearothermophilus α-glucosidase, respectively. These compounds mildly inhibited rat-intestinal sucrase and maltase. In addition, both compounds showed a mixed type of inhibition against S. cerevisiae α-glucosidase and were very stable under thermal and acidic conditions up to 60 min. The K(I) and K(IS) values of compounds 1 and 2 were 0.44 and 0.22 μg/mL, and 0.39 and 0.13 μg/mL, respectively. PRACTICAL APPLICATION: One therapeutic approach for preventing diabetes mellitus is to retard the absorption of glucose via inhibition of α-glucosidase. In this study, 2 fatty acids with strong α-glucosidase-inhibitory activity, 7(Z)-octadecenoic acid and 7(Z),10(Z)-octadecadienoic acid, were purified and identified from sea cucumber. Therefore, sea cucumber fatty acids can potentially be developed as a novel natural nutraceutical for the management of type-2 diabetes.