Secondary metabolites from the endophytic fungus Pestalotiopsis virgatula isolated from the mangrove plant Sonneratia caseolaris

Chromatographic analysis of an ethyl acetate extract of Pestalotiopsis virgatula rice cultures yielded four new α-pyrone derivatives, pestalotiopyrones I–L, and the new (6S,1′S,2′S)-hydroxypestalotin, in addition to three known compounds. The planar structures of the new compounds were elucidated on the basis of extensive NMR spectroscopic and mass spectrometric analyses. The absolute configurations of the new compounds were determined on the basis of biosynthetic considerations, coupling constants, and for pestalotiopyrone L by TDDFT ECD calculations of solution conformers.