Sugar-mimic Alkaloids from Faeces bombycis and Their Pronounced α-Glucosidase Inhibitory Activities

A new sugar-mimic alkaloid, (2R,3R,4R)-2-hydroxymethyl-3,4-dihydroxypyrrolidine- N-glyoxylamide (1) and a novel natural sugar-mimic alkaloid, (2R,3R,4R)-2-[(S)-1,2-dihydroxyethyl]piperidine-3,4-diol (2), as well as nine known compounds, were isolated and identified from Faeces bombycis. Compounds 1 and 2 showed remarkable inhibitory activity against α-glucosidase with the IC50 value of 1.9 and 6.2 μM, which were 93.4 and 28.6 potent folds than that of acarbose. The results showed that the sugar-mimic alkaloids from Faeces bombycis exhibit significant and reasonably broad range α-glucosidase inhibitory activity, which may be useful in the prevention of the postprandial hyperglycemia and provide new candidates for the treatment of diabetes mellitus.