New bioactive secondary metabolites from the Anoectochilus roxburghii endophytic fungus Aspergillus versicolor

Six new compounds, including two new isochromane lactones, versicoisochromanes A and B (1 and 2), two new benzolactones, versicobenzos A and B (3 and 4), one furancarboxylic derivate, asperfuran A (6) and one ergosterol-type steroid, asperergoster A (7), along with five known steroids (8-12), were isolated from the Anoectochilus roxburghii endophytic fungus Aspergillus versicolor. The structures of these new compounds were determined by extensive spectroscopic techniques and electronic circular dichroism (ECD) calculations. It is notable that the new compound 7 exhibited obvious IL-1 beta, NO and TNF-alpha inhibitory activity in LPS-stimulated RAW264.7 macrophages, with IC50 values of 35.5, 33.9 and 31.3 mu M, respectively. Furthermore, compounds 7 and 8 displayed potential inhibitory effects on murine splenocytes proliferation stimulated by anti-CD3/anti-CD28 monoclonal antibodies (mAbs), meanwhile suppress the lipopolysaccharide (LPS) irritated murine splenocytes proliferation.