Cyclo(dehydroala-L-Leu), an α-glucosidase inhibitor from Penicillium sp. F70614

Abstract

A diketopiperazine (1) has been isolated from the culture broth of Penicillium sp. F70614 and its structure has been determined to be cyclo(dehydroala-L-Leu) by various spectroscopic analyses. This compound selectively inhibited yeast α-glucosidase and porcine intestinal α-glucosidase with IC50 values of 35 and 50 μg/ml, respectively. However, it did not show significant inhibitory effects against almond β-glucosidase, Aspergillus α-galactosidase, Escherichia coli β-galactosidase and jack bean α-mannosidase.