[A new naphthalene derivative from bulbs of Eleutherine americana].

A new naphthalene derivative and three known compounds were isolated from the petroleum ether extract of the bulbs of Eleutherine americana by using various chromatographic techniques, such as column chromatography over silica gel and semi-preparative HPLC. Their structures were elucidated by spectroscopic date (MS, UV, IR, NMR), which were identified as eleutherol B (1), 4,8-dihydroxy-3-methoxy-1-methylanthraquinone-2-carboxylic acid methyl ester (2), 8-hydroxy-3,4-dimethoxy-1-methylanthraquinone-2-carboxylic acid methyl ester (3), and isoeleutherine (4). Compound 1 is a new compound. The diastolic blood vessels activity of compound 1 and 2 were potent, reaching 82.5% and 85.3% at the concentration of 10 µmol·L⁻¹, which were basically the same as that of the positive drug tanshinone ⅡA.