Three new nor-eremophilane sesquiterpenoids, namely nor-eremophilanol A-C (1-3), along with two known eremophilanes (4-5), were isolated from the culture of the fungus Penicillium sp. L1 that was obtained from the surface of basalt fibre composite bars. The structures of the new compounds were elucidated by a combined analysis of the 1D, 2D NMR, and HRMS spectroscopic data, and the absolute configuration of 1 was determined by the modified Mosher\'s method. The biosynthetic pathway leading to the nor-eremophilanes were proposed with the oxidative cleavage of the double bond as a key step. Compound 1 displayed antibacterial activities against the tested pathogenic bacteria.

Eleven new highly oxygenated eremophilane-type sesquiterpenoids were isolated from the whole plant of Synotis solidaginea, including two pairs of C-8 S/R epimers. The structures of the new compounds were elucidated on the basis of detailed spectroscopic analysis and the absolute configurations of 1 and 9 were confirmed by single-crystal X-ray crystallography using Cu Kα radiation. All the isolates were tested for the inhibition of LPS-stimulated NO production in macrophage-like mouse monocytic leukemia RAW264.7 cells. Compound 1 exhibited weak inhibitory effects with an IC50 of 71.2 μM.

A new eremophilane sesquiterpene, named engleromophilane (1) together with known eremoxylarin E (2) and steroids (3-7) were isolated from the fungus Engleromyces sinensis culture. The structures were deduced by the analysis of spectroscopic and MS data, together with the comparison of calculated 13C NMR chemical shifts and Electronic Circular Dichroism (ECD) spectra. Compound 1 showed cytotoxic effects against Hela, PC-3, HT29 and A549 cell lines with IC50 in the ranges of 4.84-9.48 μg/mL. Compounds 1 and 2 exhibited substantial antimicrobial activity against E. coli, S. aureus, and B. subtilis. Moreover, compounds 1-3 showed α-glucosidase inhibitory activity, in which 2 displayed a strong inhibitory effect with an IC50 value of 0.13 ± 0.01 µg/mL. This work has given additional value to the E. sinensis fungus as a remarkable bioactive compound producer, together with the possibility of increasing cultivation to industrial scales.

The extract of the whole plant of Carpesium abrotanoides L. yielded five new sesquiterpenes including four eudesmanes (1-4) and one eremophilane (5). The new compounds were characterized by spectroscopic analysis especially 1D and 2D NMR spectroscopy and HRESIMS data. Structurally, both compounds 1 and 2 were sesquiterpene epoxides and 2 owned an epoxy group at C-4/C-15 position to form a spiro skeleton. Compounds 4 and 5 were two sesquiterpenes without lactones and 5 possessed a carboxy group in the molecule. Additionally, all the isolated compounds were preliminarily evaluated for the inhibitory activity against SARS-CoV-2 main protease. As a result, compound 2 showed moderate activity with an IC50 value of 18.79 μM, while other compounds were devoid of noticeable activity (IC50 > 50 μM).

Two new eremophilane-type sesquiterpenoids, fusumaols A (1) and B (2), were isolated from the stem-leafy liverwort, Bazzania japonica collected in Mori-Machi, Shizuoka, Japan. Their structures were established using extensive spectroscopic (IR, MS, and 2D NMR) data, and the absolute configuration of 1 was determined by the modified Mosher\'s method. This is the first time eremophilanes have been discovered in the liverwort genus Bazzania. Compounds 1 and 2 were evaluated for their repellent activity against the adult population of the rice weevil Sitophilus zeamais using the modified filter paper impregnation method. Both sesquiterpenoids showed moderate repellent activities.

The genus Senecio is one of the largest in Asteraceae. There are thousands of species across the globe, either confirmed or awaiting taxonomic delimitation. While the species are best known for the toxic pyrrolizidine alkaloids that contaminate honeys (as bees select pollen from the species) and teas via lateral transfer and accumulation from adjacent roots of Senecio in the rhizosphere, they are also associated with more serious cases leading to fatality of grazing ruminants or people by contamination or accidental harvesting for medicine. Surprisingly, there are significantly more sesquiterpenoid than pyrrolizidine alkaloid-containing species. The main chemical classes, aside from alkaloids, are flavonoids, cacalols, eremophilanes, and bisabolols, often in the form of furan derivatives or free acids. The chemistry of the species across the globe generally overlaps with the 469 confirmed species of Africa. A small number of species express multiple classes of compounds, meaning the presence of sesquiterpenes does not exclude alkaloids. It is possible that there are many species that express the pyrrolizidine alkaloids, in addition to the cacalols, eremophilanes, and bisabolols. The aim of the current communication is, thus, to identify the research gaps related to the chemistry of African species of Senecio and reveal the possible chemical groups in unexplored taxa by way of example, thereby creating a summary of references that could be used to guide chemical assignment in future studies.

The investigation of the metabolites from the endophytic fungus Xylaria sp. YM 311647 in solid fermentation resulted in the isolation of six undescribed compounds, namely xylarioxides A-F, respectively. These included one eremophilane sesquiterpene, three guaiane sesquiterpene glycosides, and two ergostane glycosides. The structures of the compounds were determined by extensive analyses of spectroscopic data, including 1D and 2D NMR, as well as HRESIMS data. The stereochemistry of xylarioxide A was confirmed by X-ray crystallographic analysis. All of the isolated compounds were assayed for their antifungal activities against seven phytopathogenic fungi and two human pathogenic fungi. Among them, xylarioxides A, E and F showed potent activities against the tested phytopathogens. Particularly, xylarioxide E exhibited the highest activity against Gibberella saubinetii, Curvularia lunata, and Colletotrichum gloeosporioides with MIC values of 4, 4, and 8 μg/mL, respectively, which were comparable to the positive control of nystatin. Interestingly, guaiane sesquiterpene glycosides have been rarely reported from fungal sources. Additionally, xylarioxide E represented an unusual naturally occurring 3,4-seco-steroidal glycoside with a seven-membered lactone in ring A.

Five new sesquiterpenoids, alashanoids O-S (1-5), along with three known analogs (6-8) were isolated from the peeled stems of Syringa pinnatifolia. Their structures were elucidated by analysis of extensive spectroscopic data including ESI-MS, 1D, 2D NMR. The absolute configurations were determined by comparing its experimental and calculated electronic circular dichroism, calculated OR, calculated NMR, and single crystal X-ray diffraction data analysis. Compounds 1 and 2 belong to the seco-humulane type and possess a rare 13-membered oxygen heterocycle framework, and 3-5 belong to eremophilane-type. Compounds 1, 2, and 5 showed inhibitory effects against NO production in LPS-induced RAW264.7 macrophage cells with its IC50 values of 11.86±2.34, 72.08±7.72, and 69.22±15.29 μM, respectively, compared with the positive control indomethacin (IC50 =31.52 μM).

Fifteen new highly oxygenated eremophilane sesquiterpenoids, parasubolides A-O (1-15), were obtained from the whole plant of Parasenecio albus. The structures of 1-15 were elucidated based on the interpretation of NMR and HRESIMS data, along with experimental electronic circular dichroism (ECD) and single-crystal X-ray diffraction analysis. Compounds 1-6, and 9-14 represent the first class of 1,2,10-trioxygenated eremophilane lactones. Selected isolates were evaluated for their immunosuppressive activities. Compounds 4, 5, and 12 exhibited moderate inhibition against LPS-induced B-cell proliferation with IC50 values of 23.1, 33.8, and 26.6 μM, respectively.

Lichens, a natural source producing a number of valuable compounds is economically not feasible and profitable due to its slow growth. Mycobiont cultures are alternative sources which have become highly attractive for chemists recently. Mycobiont of Graphis sp., a native lichens in Vietnam was separated then cultivated in test tubes. The present study aimed to identify chemical constituents of the cultured mycobiont of Graphis sp. Multiple chromatographic methods were applied to isolate three eremophilane sesquiterpenes including one new compound, graphilane (1) and two known compounds sporogen-AO-1 (2) and dihydrosporogen-AO-1 (3). Their chemical structures was elucidated by extensive 1 D and 2 D NMR analysis and high resolution mass spectroscopy as well as comparisons in literature. Compound 1 was evaluated for the cytotoxic activity against K562 cancer cell line and revealed moderate activity with IC50 value of 87.20 ± 0.76 µM.