Three new α-pyrone derivatives from the soil-derived fungus Penicillium herquei MA-370

Three new α-pyrone derivatives, annularins L-N (1-3), were isolated from the EtOAc extract of Penicillium herquei MA-370, a fungus obtained from the rhizospheric soil of the mangrove plant Rhizophora mucronata. The planar structures of compounds 1-3 were determined based on comprehensive spectral interpretation of the NMR and MS data. The absolute configuration of 1 was determined by X-ray crystallographic data and that of 2 was assigned by TDDFT calculations of its ECD spectrum and cotton effects comparison with those of 1. The antimicrobial activity of compounds 1-3 was evaluated.