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Dipleosporalones A and B (1and 2), two new [2 + 2] azaphilone dimers, were obtained from a marine-derived Pleosporalessp. fungus. The absolute configurations of 1and 2were elucidated by calculations of their ECD spectra. Dipleosporalone A (1) possessed an unprecedented skeleton with an uncommon 6/4/6 ring system. Compounds 1and 2showed cytotoxicity about 30–90-fold more potent than that of their monomer pinophilin B.

Five new indole-terpenoids named penerpenes E–I (1–5), along with seven known ones (6–12), were isolated from the marine-derived fungus Penicilliumsp. KFD28 from a bivalve mollusk, Meretrix lusoria. The structures of the new compounds were elucidated from spectroscopic data and ECD spectroscopic analyses. Compound 1was assigned as an indole-diterpenoid with a unique 6/5/5/6/6/5/5 heptacyclic ring system. Compound 2represents an indole-diterpenoid with a new carbon skeleton derived from paxilline by the loss of three carbons (C-23/24/25). Compound 3contains an additional oxygen atom between C-21 and C-22 compared to paxilline to form an unusual 6/5/5/6/6/7 hexacyclic ring system bearing a 1,3-dioxepane ring, which is rarely encountered in natural products. Compounds 1, 2, 4, and 6showed inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC50values of 14, 27, 23, and 13 μM, respectively.

Ten new drimane meroterpenoids talarines A–J (1–10), along with six known analogues (11–16), were isolated from desert soil-derived fungus Talaromyces pinophilusLD-7. Their 2D structures were elucidated by comprehensive interpretation of NMR and HRESIMS data. Electronic circular dichroism calculation was used to establish their absolute configurations. Compounds 2, 10, and 11showed antiviral activities toward vesicular stomatitis virus with IC50values of 18, 15, and 23 nM, respectively. The structure-bioactivity relationship indicated that chlorine substitution at C-5 contributed greatly to their antiviral activities. Finally, we identified a new halogenase outside the biosynthetic gene cluster, which was responsible for C-5 halogenation of the precursor isocoumarin 17as a tailoring step in chlorinated meroterpenoids assembly.

Streptococcus agalactiaeis a hazardous pathogen that can cause great harm to humans and fish. In the present study, the known fungal metabolite helvolic acid (10), seven new helvolic acid derivatives named 16-O-deacetylhelvolic acid 21,16-lactone (2), 6-O-propionyl-6,16-O-dideacetylhelvolic acid 21,16-lactone (3), 1,2-dihydro-6,16-O-dideacetylhelvolic acid 21,16-lactone (4), 1,2-dihydro-16-O-deacetylhelvolic acid 21,16-lactone (5), 16-O-propionyl-16-O-deacetylhelvolic acid (6), 6-O-propionyl-6-O-deacetylhelvolic acid (7), and 24-epi-6β,16β-diacetoxy-25-hydroxy-3,7-dioxo-29-nordammara-1,17(20)-diene-21,24-lactone (9), and two known ones (1and 8) were isolated from the marine-derived fungus Aspergillus fumigatusHNMF0047 obtained from an unidentified sponge from Wenchang Beach, Hainan Province, China. The structures and the absolute configurations of the new compounds were unambiguously elucidated by spectroscopic data and electronic circular dichroism (ECD) spectroscopic analyses along with quantum ECD calculations. In addition, the spectroscopic data of compound 1are reported here for the first time, the configuration of C-24 of known compound 8was revised based on comparison of its ROESY data with its C-24 epimer 9, and the absolute configuration of 8was also determined for the first time. Compounds 6, 7, and 10showed stronger antibacterial activity than a tobramycin control against S. agalactiaewith MIC values of 16, 2, and 8 μg/mL, respectively.