Labdane-type diterpenes and austin-type meroterpenoids from the mangrove-derived fungus Talaromyces verruculosus SCSIO41706.

Four new labdane-type diterpenes talaroterpenoids W1-W4 (1-4) and three new austin-type meroterpenoids talaraustinoids A-C (5-7) along with six known analogues (8-13) were isolated from the mangrove sediment derived fungus Talaromyces verruculosus SCSIO41706. Their structures were determined by extensive spectroscopic analysis, and their absolute configurations were further confirmed by ECD calculations or X-ray diffraction analysis. Among these compounds, 1-3 and 9 were diastereoisomers, and 7 and 13 were epimers, which displayed the configurational diversities of labdane-type diterpenes and austin-type meroterpenoids. Compounds 1-13 exhibited significant toxicity in brine shrimp lethality assays, and 4 was the strongest with the IC50 value of 2.5 μg/mL. A preliminary structure-toxicity relationship of labdane-type diterpenes was discussed.