Neuroprotective diterpenes from the fruiting body of Antrodia camphorata

Three new compounds, 19-hydroxylabda-8(17)-en-16,15-olide ( 1), 3 beta,19- dihydroxylabda-8(17), 11E- dien-16,15-olide ( 2), and 13-epi-3 beta,19-dihydroxylabda- 8( 17), 11E-dien-16,15-olide ( 3), together with four known compounds, 19-hydroxylabda- 8( 17), 13-dien-16,15-olide ( 4), 14-deoxy-11,12-didehydroandrographolide ( 5), 14-deoxyandrographolide, and pinusolidic acid, were isolated from the fruiting bodies of Antrodia camphorata. The structures of compounds 1-3 were elucidated by the analysis of their spectroscopic data. The in vitro neuroprotective activity of all compounds was evaluated, and compounds 1-5 protected neurons from A beta damage by 39.2, 35.0, 36.7, 30.6, and 27.0%, respectively, at concentrations between 5 and 20 mu M.