Structural Elucidation of Three Anthraquinones from a Marine-Derived Mangrove Endophytic Fungus (Isolate 1850)

Anthracycline antibiotics now were used extensively as clinic medicines, but new anthracyclines with novel bioactivities are still urgently needed because of the drug-resistant problem. During our screening for lead compounds from marine fungi from the South China Sea, three anthraquinones (1-3) were found to be produced by the marine-derived endophytic fungus isolate 1850 from a leaf of Kandelia candel from an estuarine mangrove in Hong Kong. Their structures were elucidated as averufin (1), nidurufin (2) and versicolorin C (3) by analysis of spectroscopic data. These three anthraquinones had also been obtained from another marine fungus (isolate 2526). The results that the same metabolites were produced by two different fungal strains derived from two different species mangrove plants shows the presence of some close connections between the two fungal strains and the two species mangrove plants.