Structure Revision and Protein Tyrosine Phosphatase Inhibitory Activity of Drazepinone

From the marine-derived fungus Penicillium sumatrense (Trichocomaceae), a pair of enantiomers [(+)-1 and (-)-1] were isolated with identical 1D NMR data to drazepinone, which was originally reported to have a trisubstituted naphthofuroazepinone skeleton. In this study, we confirmed the structures of the two enantiomers as drazepinone and revised their structures by detailed analysis of extensive 2D NMR data and a comparison of the calculated C-13 chemical shifts, ECD, VCD, and ORD spectra with those of the experiment ones. (+)-1 and (-)-1 were evaluated for their PTP inhibitory activity in vitro. (-)-1 showed selective PTP inhibitory activity against PTP1B and TCPTP with IC50 values of 1.56 and 12.5 mu g/mL, respectively.

Automated summary

A pair of enantiomers were isolated from the marine-derived fungus Penicillium sumatrense, with one showing selective PTP inhibitory activity against PTP1B and TCPTP. The structures were confirmed as drazepinone through detailed analysis of 2D NMR data and comparisons with calculated chemical shifts and spectra.