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Eight new cadinane sesquiterpenoids ( 1 - 8 ), along with two known compounds ( 9 and 10 ), were isolated from infected stems of the semi-mangrove plant, Hibiscus tiliaceus . The structures of compounds 1 - 8 were elucidated through the analysis of their 1D and 2D NMR and MS data, and their absolute configurations were determined by comparing their experimental and calculated ECD spectra and by single-crystal X-ray diffraction. The two confused known compounds ( 9 and 10 ) were resolved using single-crystal X-ray crystallography. Compounds 1 - 3 have novel norsesquiterpene carbon skeletons arising from a ring contraction rearrangement. All obtained isolates were evaluated against the HepG2 and Huh7 cell lines, and compounds 1b , 2b , 4 , 6 , and 8 showed cytotoxic activity toward both cell lines, with IC 50 values ranging from 3.5 to 6.8 μM.

Two new meroterpenoids, aspermeroterpenes D and E ( 1 and 2 ), two new ophiobolin-type sesterterpenoids, the C-18 epimers of 18,19-dihydro-18-methoxy-19-hydroxyophiobolin P ( 6 and 7 ), and two new drimane-type sesquiterpenoids, 3 S -hydroxystrobilactone A ( 8 ) and 6- epi -strobilactone A ( 9 ), along with 11 known terpenoids ( 3 - 5 and 10 - 17 ) were isolated from the cultures of the algicolous fungus Aspergillus sp. RR-YLW-12, derived from the red alga Rhodomela confervoides . The structures and relative configurations of new compounds were established by detailed spectroscopic analysis of NMR and HRMS experiments, and the absolute configurations were assigned by X-ray diffraction experiments and comparison of their experimental and calculated ECD spectra. Compound 1 features a rare 6/6/6/6/5 pentacyclic system with a meroterpenoid skeleton, and the structure of terretonin E ( 3 ) was revised in this study. Compound 4 showed significant inhibitory activities against three microalgae, Prorocentrum donghaiense , Heterosigma akashiwo , and Chattonella marina , with IC 50 values of 10.5, 5.2, and 3.1 μg/mL, respectively.

Biological species collections are critical for natural product drug discovery programs. However, prioritization of target species in massive collections remains difficult. Here, we introduce an untargeted metabolomics-based prioritization workflow that uses MS/MS molecular networking to estimate scaffold-level distribution. As a demonstration, we applied the workflow to 40 polyporoid fungal species. Nine species were prioritized as candidates based on the chemical structural and compositional similarity (CSCS) metric. Most of the selected species showed relatively higher richness and uniqueness of metabolites than those of the others. Cryptoporus volvatus , one of the prioritized species, was investigated further. The chemical profiles of the extracts of C. volvatus culture and fruiting bodies were compared, and it was shown that derivative-level diversity was higher in the fruiting bodies; meanwhile, scaffold-level diversity was similar. This showed that the compounds found from a cultured fungus can also be isolated in wild mushrooms. Targeted isolation of the fruiting body extract yielded three unknown ( 1 - 3 ) and six known ( 4 - 9 ) cryptoporic acid derivatives, which are drimane-type sesquiterpenes with isocitric acid moieties that have been reported in this species. Cryptoporic acid T ( 1 ) is a trimeric cryptoporic acid reported for the first time. Compounds 2 and 5 exhibited cytotoxicity against HCT-116 cell lines with IC 50 values of 4.3 and 3.6 μM, respectively.

Bioactivity-guided isolation of Aspergillus ustus led to the discovery of five new drimane sesquiterpenes, named ustusal A, ustusolate F and G, and ustusoic acid A and B, 1 - 5 respectively. Structural elucidation of these fungal terpenes relied on 1D and 2D NMR techniques, high-resolution mass spectrometry, and chiroptical properties. Their relative configurations were determined by NMR methods, while the absolute configurations were established using comparative analyses of computed and experimental NMR chemical shifts and ECD spectra. The sesquiterpenes exhibited weak activity against the clinically relevant pathogens vancomycin-resistant Enterococcus faecium and multidrug-resistant Staphylococcus aureus ; however, the activity of 5 was drastically enhanced when equal amounts of stromemycin ( 6 ), a known metabolite coisolated from the same fraction from A. ustus , was added.

Paraconiothins A-J ( 1 - 10 ), 10 new sesquiterpenoids, as well as five known sesquiterpenoids, were isolated from the cultures of the endophytic fungus Paraconiothyrium brasiliense ECN-258. The structures of the sesquiterpenoids were elucidated by extensive spectroscopic analysis. Furthermore, the absolute structures of 7 and 8 were determined by comparing their experimental and computed electronic circular dichroism data. Paraconiothins A-G ( 1 - 7 ) were eremophilane sesquiterpenoids, while paraconiothins H-J ( 8 - 10 ) had new or rare carbon frameworks that are possibly biosynthesized by a pathway involving the rearrangement of eremophilane sesquiterpenoids. Paraconiothins C ( 3 ) and I ( 9 ) exhibited an inhibitory effect on the liver X receptor α at a concentration of 50 μM.

The presence of excessive osteoclasts is a major factor in skeletal diseases. The present study aimed to discover osteoclast differentiation inhibitors from the basidiomycete Xylodon flaviporus . Seven new drimane sesquiterpenoids ( 1 - 7 ) and 7-ketoisodrimenin-5-ene ( 8 ) were obtained and characterized by various spectroscopic methods. The isolated compounds were evaluated for their inhibitory effects against receptor activator of nuclear factor-kappa-B ligand-induced osteoclastogenesis in mouse bone marrow macrophages. Compounds 1 , 3 , and 6 showed potent activities with IC 50 values of 1.6, 0.9, and 2.1 μM, respectively, while 4 , 5 , and 7 exhibited relatively weak activities with IC 50 values of 10.7, 10.1, and 8.5 μM, respectively.