Bioassay-guided fractionation of the organic extract from a culture of Phom
opsis longicolla, an endophytic fungus of the endangered mint Dicerandra fr
utescens, led to the isolation of dicerandrols A, B, and C. Extensive NMR a
nd HRFABMS experiments were used to identify these new yellow antibiotic an
d cytotoxic compounds as 2,2 ' -dimeric tetrahydroxanthones.