Six new isocoumarin derivatives, exserolides A-F (1-6), were isolated from solid cultures of the plant endophytic fungus Exserohilum sp., together with four known metabolites (7-10). The structures of 1-6 were elucidated primarily by NMR experiments. The absolute configuration of the C-3 methine carbon in 1-5 was deduced via the circular dichroism data, whereas that of the 1,3-diol moiety in 6 was assigned from the (1)H NMR data of its (R)- and (S)-MTPA diesters. Compounds 3 and 9 showed antifungal activity against the plant pathogen Fusarium oxysporum, whereas 6 displayed significant inhibitory effects against a small panel of bacteria.
Keywords: (12R)-12-hydroxymonocerin (PubChem CID: 24896700); (12S)-12-hydroxymonocerin (PubChem CID: 24896699); (–)-mellein (PubChem CID: 114679); 11-hydroxymonocerin (PubChem CID: 25111599); Antibacterial activity; Antifungal activity; Endophytic fungus; Exserohilum sp.; Isocoumarins; Lasionectrin (PubChem CID: 60155242); Monocerin (PubChem CID: 92267).
Copyright © 2014 Elsevier B.V. All rights reserved.