title: Identification of a new naphthalene and its derivatives from the bulb of eleutherine americana with inhibitory activity on lipopolysaccharide-induced nitric oxide production.
abstract: 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 IC(50) values of 7.7, 11.4, 19.8, 21.7, and 34.4 microM, 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.
authors.affiliation: College of Pharmacy and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul Korea.
authors.forename: Ah-Reum
authors.initials: AR
authors.lastname: Han
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Min
authors.forename: Joo-Won
authors.initials: JW
authors.lastname: Nam
authors.forename: Na-Youn
authors.initials: NY
authors.lastname: Lee
authors.forename: Adam
authors.initials: A
authors.lastname: Wiryawan
authors.forename: Wahyu
authors.initials: W
authors.lastname: Suprapto
authors.forename: Sang Kook
authors.initials: SK
authors.lastname: Lee
authors.forename: Kang Ro
authors.initials: KR
authors.lastname: Lee
authors.forename: Eun-Kyoung
authors.initials: EK
authors.lastname: Seo