Isolation and structure determination of a cholesterol esterase inhibitor from Ganoderma lucidum

Bioassay-guided fractionation of methanol extract of Ganoderma lucidum gave a pure cholesterol esterase inhibitor. On the basis of spectroscopic analysis and comparison with data from the literature, its structure was identified as 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (compound I). Compound (I) inhibited cholesterol esterase with an IC50 value of 42 micronM. A Lineweaver-Burk plot revealed that the compound (I) is a noncompetitive inhibitor. Findings from this study suggest that compound (I) may be the active principle of the hypocholesterolemic effect of Ganoderma lucidum.