Neomacrodione: a new degraded diterpenoid from the roots of <i>Neoboutonia macrocalyx</i> Beng (Euphorbiaceae)

One new degraded diterpenoid 3,6-dihydroxy-1,7-dimethyl-9,10-phenantroquinone (neomacrodione) (<b>1</b>) together seven known compounds were isolated from the roots of <i>Neoboutonia macrocalyx</i> (Euphorbiaceae). The structures of the compounds were established based on their NMR and mass spectrometric data in conjunction with those previously reported in the literature. Compound (<b>1</b>) displayed moderate antibacterial activities.