The present study was undertaken to isolate component(s) which contributes to the hypocholesterolemic action of Ningyotake (Polyporus confluens) mushroom. The mushroom powder was extracted with 80% ethanol, and the extract and residue were fractionated into five fractions according to the solubility to solvents. When each fraction was added to a diet containing 1% cholesterol and 0.25% sodium cholate and fed to rats, the plasma cholesterol level was significantly decreased only by ethyl acetate-soluble fraction. Therefore, ethyl acetate-soluble fraction was further fractionated by silica gel column chromatography. Two major compounds, which comprised 45.0% and 28.5% of the ethyl acetate-soluble fraction, were obtained in a pure form by the chromatography, and the compounds were identified as grifolin (2-trans, trans-farnesyl-5-methylresorcinol) and neogrifolin (4-trans, trans-farnesyl-5-methylresorcinol), respectively. The addition of grifolin and neogrifolin to the high cholesterol diet was found to lower plasma cholesterol level significantly.
