Pestaloquinols A and B, Isoprenylated Epoxyquinols from Pestalotiopsis sp.

Two new isoprenylated epoxyquinol derivatives, pestaloquinols A (2) and B (3), and their putative biosynthetic precursor, cytosporin D (1), were isolated from the crude extract of the plant endophytic fungus Pestalotiopsis sp. The structures of these compounds were elucidated primarily by NMR experiments. Pestaloquinols A (2) and B (3) possess a previously undescribed nonacyclic ring system and showed cytotoxicity against HeLa cells.