The 2,3-epoxy naphthoquinol produced by endophyte Arthrinium marii M-211

Abstract

A novel 2,3-epoxy naphthoquinol, named (6R,7R,8R)-theissenone A (1), possessing an oxatricyclo[5.4.0.03,5]undeca-trien-2-one skeleton, together with two known compounds, (6S,7R,8R)-theissenone (2) and arthrinone (3), were produced by an endophytic fungus, Arthrinium marii M-211, which was isolated from mangrove plants. The structure of 1, including the absolute stereochemistry, was elucidated by analysis of nuclear magnetic resonance (NMR) and mass spectrometry (MS) data and timedependent density functional theory (TDDFT) calculations of electronic circular dichroism (ECD) spectra. Additionally, the absolute structure of 2 was deduced as a diastereomer of 1 using ECD spectral data analysis. Compounds 1, 2 and 3 exhibited cytotoxic activity against the H4IIE rat hepatoma cells, with IC50 values of 67.5, 46.6 and 13.4 mM, respectively.