Production, isolation and structure determination of a novel .BETA.-glucosidase inhibitor, cyclophellitol, from Phellinus sp.

Abstract
In the course of our screening of .beta.-glucosidase inhibitor, a culture filtrate of a mushroom, Phellinus sp. strongly inhibited the enzyme activity. The active substance was isolated through charcoal separation, column chromatography and crystallization. Spectroscopic and crystallographic analysis revealed that it had a novel cyclitol structure, (1S,2R,3S,4R,5R,6R)-5-hydroxymethyl-7-oxabicyclo[4,1,0]heptane-2,3,4-triol, and we named it cyclophellitol. It inhibited almond-derived .beta.-glucosidase with an IC50 of 0.8 .mu.g/ml.