Epiconone, one novel cyclohexenone from endophytic fungi Epicoccum sp. 1-042.

Targeting drug-resistant Acinetobacter baumannii, two fungal strains, Epicoccum sp. 1-042 and Penicillium sp. 19-115, were identified from 35 fungi isolated from Tibet. Bioassay-guided isolation from Epicoccum sp. 1-042 yielded a novel cyclohexenone, epiconone (1), and parasitenone (2), while patulin (3) was isolated from Penicillium sp. 19-115. Structural elucidation was accomplished through comprehensive spectroscopic analysis and quantum chemistry calculations. The biosynthetic pathways of compounds 1 and 2 were proposed based on bioinformatics analysis. Compounds 1 - 3 exhibited antibacterial activity against carbapenem-resistant Acinetobacter baumannii (CRAB) with MIC values ranging from 4 to 128 μg mL-1.