Dicerandrols, new antibiotic and cytotoxic dimers produced by the fungus Phomopsis longicolla isolated from an endangered mint

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.