2008 Volume 56 Issue 9 Pages 1314-1316
A new naphthoquinone, (−)-3-[2-(acetyloxy)propyl]-2-hydroxy-8-methoxy-1,4-naphthoquinone (1) was isolated from the bulb of Eleutherine americana MERR. et HEYNE (Iridaceae) together with two known compounds, eleutherinol (6) and 1,5-dihydroxy-3-methylanthraquinone (7) which were found in this species for the first time. The other known compounds, (−)-isoeleutherin (2), (+)-eleutherin (3), (−)-hongconin (4), and (+)-dihydroeleutherinol (5) which were reported previously from this species, were also isolated in the present study. Compounds 2—6 exhibited potent inhibitory activity on nitric oxide production in RAW 264.7 lipopolysaccharide-activated mouse macrophage cells with IC50 values of 7.7, 11.4, 19.8, 21.7, and 34.4 μM, respectively, whereas the other two compounds, 1 and 7, were inactive. The structure of compound 1 was elucidated by spectroscopic data analysis including 1D and 2D NMR experiments.
