New Fusaric Acid Derivatives from the Endophytic Fungus Fusarium oxysporum and Their Phytotoxicity to Barley Leaves

Chemical investigation of the endophytic fungus Fusarium oxysporum isolated from fruits of Drepanocarpus lunatus afforded eight new fusaric acid derivatives, fusaricates A–G, 1–7, and 10-hydroxy-11-chlorofusaric acid, 8, along with four known compounds. Their structures were elucidated by one- and two-dimensional NMR as well as MS data and by comparison with the literature. The absolute configurations of fusaricates C–E, 3–5, were determined using chiral GC-MS. Fusaricates A–G, 1–7, represent the first examples of fusaric acid linked to a polyalcohol moiety via an ester bond. All isolated fusaric acid derivatives 1–8 showed significant phytotoxicity to leaves of barley.