Furan Derivatives and Polyketides from the Fungus Irpex lacteus

Boerechalasins A-G, cytochalasans from the fungus Boeremia exigua with anti-inflammatory and cytotoxic activities

Seven previously undescribed cytochalasans, namely, boerechalasins A-G, together with one analogue, were characterized from the solid culture of the fungus Boeremia exigua. Their structures and absolute configurations were elucidated on the basis of extensive spectroscopic analysis as well as electronic circular dichroism calculations. Remarkably, boerechalasin F possessed an unusual sulfoxide moiety that might be derived from methionine, while boerechalasin G had an unusual 5-methylcyclohexane-1,2,3-triol substituent at N-2 position. Boerechalasins A and E exhibited inhibitory activities against nitric oxide production in LPS-induced RAW264.7 macrophages with IC50 values of 21.9 and 5.7 μM, respectively. Boerechalasin F displayed cytotoxicity against human MCF‒7 cells with an IC50 value of 22.8 μM.

Polyketides from the fungus Pochonia chlamydosporia and their bioactivities

Three previously undescribed griseofulvin derivatives, namely pochonichlamydins A-C, one small polyketide, namely pochonichlamydin D, together with nine known compounds, have been isolated from cultures of the fungus Pochonia chlamydosporia. Their structures with absolute configurations were elucidated on the basis of extensive spectrometric methods and single-crystal X-ray diffraction. Dechlorogriseofulvin and griseofulvin exhibited inhibitory activities against Candida albicans at the concentration of 100 μM, with inhibition rates of 69.1% and 56.3%, respectively. Meanwhile, pochonichlamydin C showed mild cytotoxicity against the human cancer MCF-7 cell line with an IC₅₀ value of 33.1 μM.

Lanostane triterpenoids from the fungus Physisporinus vitreus and their inhibitory activity against nitric oxide production

Eight undescribed lanostane triterpenoids, physivitrins A-H, along with four known analogues, were isolated from cultures of the fungus Physisporinus vitreus. Their structures were elucidated on the basis of extensive spectroscopic methods, in which the absolute configuration of physivitrin A was elucidated using electronic circular dichroism calculation and nuclear magnetic resonance (NMR) calculation with DP4+ analysis. Physivitrins B and C showed inhibitory activities against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages with IC₅₀ values of 7.5 and 23.5 μM, respectively. Meanwhile, proinflammatory cytokines (TNF-α, iNOS and IL-1β) mRNA expression was also inhibited by physivitrin B significantly.

Sesquiterpenoids and furan derivatives from the Orychophragmus violaceus (L.) O.E. Schulz endophytic fungus Irpex lacteus OV38

Nine undescribed compounds, including six tremulane-type sesquiterpenoids, irpexolaceus A-F, one phenolic bisabolane-type sesquiterpenoid, irpexolaceus G, and two furan derivatives, irpexonjust A-B, as well as eight known analogs, were isolated from an endophytic fungus (Irpex lacteus OV38) of Orychophragmus violaceus (L.) O.E. Schulz, a Chinese medicinal and edible plant. The structures of these natural compounds were elucidated based on NMR, HRESIMS, single-crystal X-ray diffraction, and ECD spectroscopic data. Among the tested isolates (50 μg/mL), the inhibitory effects of irpexolaceus A, C, D, F, and G, irpexonjust B, and irpexlacte B against NO release from LPS-induced RAW 264.7 cells were higher than 45%, while irpexlacte C (42.6%), irpexolaceus B (39.6%), irpexonjust A (43.7%), and irpexolaceus E (33.6%) exhibited weaker inhibitory effects on the release of NO.

Psathyrellins A-E, Antibacterial Guanacastane Diterpenoids from Mushroom Psathyrella candolleana

Five previously undescribed guanacastane diterpenoids, namely psathyrellins A-E (1-5), were obtained from cultures of the mushroom Psathyrella candolleana. Their structures with absolute configurations were elucidated by extensive spectroscopic methods. Compounds 1-3 showed antibacterial activity against four strains with MIC values in a range of 16-128 μg/mL.

Two new pyridine derivatives and two new furan derivatives from Irpex lacteus

Two undescribed disubstituted pyridine derivatives irpexidines A and B (1 and 2) and two undescribed alkylfuran derivatives irpexins K and L (3 and 4) were isolated from fermentation broth of Irpex lacteus. Their structures were established by extensive spectroscopic methods. The pyridine derivatives from this fungus were reported for the first time. The new compounds were evaluated for their cytotoxicity against Hela cancer cell and inhibitory activity on NO production.