Two Unsaturated Fatty Acids with Potent α‐Glucosidase Inhibitory Activity Purified from the Body Wall of Sea Cucumber ( Stichopus japonicus )

  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.