Aromatic compounds from the halotolerant fungal strain of Wallemia sebi PXP-89 in a hypersaline medium.

A new cyclopentanopyridine alkaloid, 3-hydroxy-5-methyl-5,6-dihydro-7H-cyclopenta[b]pyridin-7-one (1), together with 11 known aromatic compounds were isolated from the secondary metabolites of the halotolerant fungal strain Wallemia sebi PXP-89 in 10% NaCl. Their structures including the absolute configurations of (2S,3S)-1-(4-hydroxyphenyl)butane-2,3-diol (2), (2R,3S)-1-(4-hydroxyphenyl)butane-2,3-diol (3), and (S)-3-hydroxy-4-(4-hydroxyphenyl)-2-one (4) were elucidated by spectroscopic analysis and a modified Mosher's method. Compound 1 exhibited antimicrobial activity against Enterobacter aerogenes with a MIC of 76.7 μM. The absolute configurations of compounds 2-4 were determined for the first time.