Cytotoxic and Antibacterial Meroterpenoids Isolated from the Marine-Derived Fungus Talaromyces sp. M27416.

Three novel meroterpenoids, taladrimanins B-D ( 1 - 3 ), were isolated from the marine-derived fungus Talaromyces sp. M27416, alongside three biogenetically related compounds ( 4 - 6 ). We delineated taladrimanin B's ( 1 ) structure using HRESIMS and NMR, confirmed its configuration via quantum chemical NMR analysis and DP4+ methodology, and verified it through X-ray crystallography. ECD calculations determined the absolute configuration of compound 1 , while comparative NMR and ECD analyses elucidated the absolute configurations of 2 and 3 . These compounds are drimane-type meroterpenoids with a C10 polyketide unit (8 R -configuration). We proposed a biosynthetic pathway and noted that compound 1 showed cytotoxic activity against MKN-45 and 5637 cell lines and selective antibacterial effects against Staphylococcus aureus CICC 10384.