Chemical examination of the EtOAc extract of the deep sea-derived fungus Penicillium sp. YPGA11 resulted in the isolation of four new farnesylcyclohexenones, peniginsengins B⁻E (1⁻4), and a known analog peniginsengin A (5). The structures of compounds 1⁻4 were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of 1, 2, and 4 were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compounds 1⁻5, characterized by a highly oxygenated 1-methylcyclohexene unit and a (4E,8E)-4,8-dimethyldeca-4,8-dienoic acid side chain, are rarely found in nature. Compounds 2⁻4 exhibited antibacterial activity against Staphylococcus aureus.
Keywords: Penicillium sp.; antibacterial; deep sea-derived fungus; farnesylcyclohexenones.