Five new (fusarisolins A⁻E, 1 to 5) and three known (6 to 8) polyketides were isolated from the marine-derived fungus Fusarium solani H918, along with six known phenolics (9 to 14). Their structures were established by comprehensive spectroscopic data analyses, methoxyphenylacetic acid (MPA) method, chemical conversion, and by comparison with data reported in the literature. Compounds 1 and 2 are the first two naturally occurring 21 carbons polyketides featuring a rare β- and γ-lactone unit, respectively. All isolates (1 to 14) were evaluated for their inhibitory effects against tea pathogenic fungus Pestalotiopsis theae and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase gene expression. Compound 8 showed potent antifungal activity with an ED50 value of 55 μM, while 1, 8, 13, and 14 significantly inhibited HMG-CoA synthase gene expression.
Keywords: HMG-CoA synthase; bioactivity; microorganisms; ocean; β-lactones.