Xanthones from Hypericum roeperanum.

Four new xanthones have been isolated from the roots of Hypericum roeperanum. Their structures have been established by a combination of spectroscopic and chemical methods as 1,6-dihydroxy-5-methoxy-4',5'-dihydro-4',4',5'-trimethylfurano- (2',3':3,4)-xanthone (5-O-methyl-2-deprenylrheediaxanthone B), 1,6-dihydroxy-5-methoxy-6',6'-dimethylpyrano-(2',3':3,4)-xanthone (5-O-methylisojacareubin), 1,3,5,6-tetrahydroxy-2-(2',2'-dimethyl-4'-isopropenyl)-cyclopen tanylxanthone (5-O-demethylpaxanthonin) and 1,3,5,6-tetrahydroxy-4-trans-sesquilavandulylxanthone (roeperanone). In addition, 2-hydroxyxanthone, 5-hydroxy-2-methoxyxanthone, 1,5-dihydroxy-2-methoxyxanthone, 2-deprenyl rheediaxanthone B, isojacareubin and calycinoxanthone D have been isolated and characterized. Some of the isolated xanthones exhibited antifungal activity against Candida albicans.