Kojicone C, new anti-inflammatory polyketide from insect-associated fungus Aspergillus versicolor

The chemical study of EtOAc extracts of the insect-associated fungus Aspergillus versicolor led to the isolation of a new polyketide kojicone C ( 1 ) and its precursor (2 R ,4 R )−4-hydroxy-5-methoxy-2,4-dimethyl-2-[(2 R )−2-methylbutyryloxy]−5-cyclohexen-1,3-dione ( 2 ). Kojicone C belongs to the rare tricycle cyclohexen-1,3-dione adduct class. The structures of 1 and 2 were determined by HRESIMS (high resolution electrospray ionization mass spectroscopy) data, 1D and 2 D NMR (nuclear magnetic resonance) spectroscopic analysis, ECD (electronic circular dichroism) calculations, and CD exciton chirality method. Compound 1 exhibited moderate anti-inflammatory activities that reduced LPS-induced NO production of RAW 264.7 cells (IC 50 = 35.8 μ Μ). It could also significantly inhibit LPS-induced mRNA expression of TNF- α , IL-1 β , and IL-6 of this cell line at a concentration of 20 μ Μ. • One new polyketide was isolated from Aspergillus versicolor . • The new compound is a rare tricycle cyclohexen-1,3-dione adduct. • The new compound exhibited potent anti-inflammatory activities.