Cytosporins F-K, new epoxyquinols from the endophytic fungus Pestalotiopsis theae

Chemical investigation of an endophytic fungus, Pestalotiopsis theae, isolated from the leaves of Turraeanthus longipes (Meliaceae) collected in Cameroon, resulted in the isolation of six new epoxyquinols, cytosporins F-K (2-7), together with the known cytosporin D (1). The structures of the new compounds were unambiguously determined by analysis of the 1D, 2D NMR, and HRMS spectra. Cytosporins G-K (3-7) are the first cytosporins with a hydroxyl substituted C7 side chain, while cytosporins F-I (2-5) contain a 13-acetoxyl group that was not reported previously. A plausible biosynthetic pathway for the cytosporin derivatives is proposed.