Citrinin dimeric derivatives are bioactive polyketides previously reported from Penicillium, Aspergillus, and Monascus fungi species. Due to the large distance between the stereogenic centers of the two monomer units, it was difficult to determine the absolute configuration of the whole molecule (1). In previous work, the absolute configuration of 1 was just proposed by biogenetic considerations. To address this problem, the experimental VCD of 1 was compared with the corresponding DFT calculations for two diastereomers (1a and 1b). Also, the experimental ECD and NMR spectra of 1 were combined for analysis with the corresponding theoretical predictions for different diastereomers. Additionally, compound 1 showed promising anti-Vibrio activity against pathogenic Vibrio spp.with MIC values ranging from 0.4 to 0.8 μM.

A fungal strain, Pleosporales sp. CF09-1, was isolated from marine sediment collected from the Bohai Sea. A novel azaphilone derivative, named pleosporalone A (1), along with two known analogues, cohaerins A and B (2 and 3), were obtained and identified from the culture extract of Pleosporales sp. CF09-1. Their planar structures were elucidated by detailed analysis of spectroscopic data and by comparison with related known compounds. Pleosporalone A (1) represents the first azaphilone derivative characterised with A-ring aromatisation. Compound 1 showed strong antifungal activity against three plant pathogenic fungi Botrytis cinerea, Rhizopus oryzae and Phytophthora capsici with the MIC values of 0.39, 0.78 and 0.78 μM, respectively.

No abstract

A pair of enantiomeric 4-oxabicyclic[4.3.0]lactam derivatives, (+)- and (-)-penicilactam A (1), and one new polyketide derivative penicitrinone F (2) were isolated from the marine-derived fungus Penicillium griseofulvum GT-10. Their structures and absolute configurations were elucidated through extensive spectroscopic analyses combined with the calculated ECD spectra. Penicitrinone F (2) had moderate inhibitory activity towards Bacillus subtilis with a MIC value of 6.3 μM.

One new oxygenated steroid, named aspersteroid A (1), and three known analogues (2-4) were isolated from the marine-derived fungus Aspergillus flavus collected from the Bohai Sea. Their structures were elucidated by spectroscopic analyses and by comparison with previously reported data. The absolute configuration of tetracyclic nucleus in 1 was assigned by quantum chemical calculation of the electronic circular dichroism (ECD) spectrum. All the compounds were evaluated for their cytotoxic and antibacterial activities.