A chemical study of the ethyl acetate (EtOAc) extract from the deep-sea-derived fungus Penicillium thomii YPGA3 led to the isolation of a new austalide meroterpenoid (1) and seven known analogues (2−8), two new labdane-type diterpenoids (9 and 10) and a known derivative (11). The structures of new compounds 1, 9, and 10 were determined by comprehensive analyses via nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data. The absolute configurations of 1, 9, and 10 were determined by comparisons of experimental electronic circular dichroism (ECD) with the calculated ECD spectra. Compound 1 represented the third example of austalides bearing a hydroxyl group at C-5 instead of the conserved methoxy in other known analogues. To our knowledge, diterpenoids belonging to the labdane-type were discovered from species of Penicillium for the first time. Compound 1 showed cytotoxicity toward MDA-MB-468 cells with an IC₅₀ value of 38.9 μM. Compounds 2 and 11 exhibited inhibition against α-glucosidase with IC₅₀ values of 910 and 525 μM, respectively, being more active than the positive control acarbose (1.33 mM).

A new indole diterpene, named penicindopene A (1), together with seven known compounds (2 – 8), was isolated from the deep-sea fungus Penicillium sp. YPCMAC1. The structure of penicindopene A was elucidated by extensive spectroscopic analyses (1 D and 2 D NMR, and HRESIMS data), in addition to the ECD calculations for the assignments of its absolute configuration. Penicindopene A represented the first example of indole diterpenes possessing a 3-hydroxyl-2-indolone moiety, and it exhibited moderate cytotoxicities against A549 and HeLa cell lines with IC₅₀ values of 15.2 and 20.5 µM, respectively.

Three new butenolide derivatives, namely aspernolides N–P (1–3), together with six known analogues (4–9), were isolated from the ethyl acetate (EtOAc) extract of the deep sea-derived fungus Aspergillus terreus YPGA10. The structures of compounds 1–3 were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of 1 and 2 were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compound 1 represents the rare example of Aspergillus-derived butenolide derivatives featured by a monosubstituted benzene ring. Compounds 6–9 exhibited remarkable inhibitory effects against α-glucosidase with IC₅₀ values of 3.87, 1.37, 6.98, and 8.06 μM, respectively, being much more active than the positive control acarbose (190.2 μM).