Ganoderol B: a potent α-glucosidase inhibitor isolated from the fruiting body of Ganoderma lucidum

α-Glucosidase inhibitor has considerable potential as a diabetes mellitus type 2 drug because it prevents the digestion of carbohydrates. The search for the constituents reducing α-glucosidase activity led to the finding of active compounds in the fruiting body of Ganoderma lucidum. The CHCl(3) extract of the fruiting body of G. lucidum was found to show inhibitory activity on α-glucosidase in vitro. The neutral fraction, with an IC(50) of 88.7 μg/ml, had stronger inhibition than a positive control, acarbose, with an IC(50) of 336.7 μg/ml (521.5 μM). The neutral fraction was subjected to silica gel column chromatography and repeated p-HPLC to provide an active compound, (3β,24E)-lanosta-7,9(11),24-trien-3,26-diol (ganoderol B). It was found to have high α-glucosidase inhibition, with an IC(50) of 48.5 μg/ml (119.8 μM).