New secondary metabolites from the mangrove endophytic fungus Aspergillus versicolor

Two new oxoindolo diterpene epimers, anthcolorin G 1 and anthcolorin H 2, nine new meroterpenes, (7R,8R)-8-hydroxysydowic acid 4, (7S,10S)-10-hydroxy-sydowic acid 5, (7S,11R)-12-hydroxy-sydowic acid 6, (7S,11R)-12-acetoxy-sydowic acid 7, (7R,8R)-1,8-epoxy-11-hydroxy-sydonic acid 9, 7-deoxy-7,14-didehydro-11-hydroxy-sydonic acid 11, 7-deoxy-7,14-didehydro-12-acetoxy-sydonic acid 14, and (E)-7-deoxy-7,8-didehydro-12-acetoxy-sydonic acid 15, (7R)-11-hydroxy-sydonic acid methyl ester 18, and a benzoic acid derivative, isolated for the first time from a natural source, 3-hydroxy-4-(1-oxo-ethane)benzoic acid 10, in addition to twelve known compounds were isolated from the solid rice culture of the endophytic fungus Aspergillus versicolor. Their structures were determined by one- and two-dimensional NMR spectroscopy, high resolution electrospray ionization mass and circular dichroism spectra. Their cytotoxic activity was evaluated using Hela cells.