Eremophilenolides and Other Constituents from the Roots of Ligularia sagitta

Abstract

Chemical investigation of the roots of Ligularia sagitta has resulted in the characterization of six eremophilenolides 6β,8β-dimethoxy-10β-hydroxyeremophil-7(11)-en-12,8α-olide (1), 6β-angeloyloxy-10β-hydroxy-8β-methoxyeremophil-7(11)-en-12,8α-olide (2), 6β-(2′-methylbutanoyloxy)-10β-hydroxy-8β-methoxyeremophil-7(11)-en-12,8α-olide (3), 6β-angeloyloxy-10β-hydroxy-8α-methoxyeremophil-7(11)-en-12,8β-olide (4), 6β-(2′-methylbutanoyloxy)-10β-hydroxy-8α-methoxyeremophil-7(11)-en-12,8β-olide (5) and 8β,10β-dihydroxy-6β-methoxyeremophil-7(11)-en-12,8α-olide (6), together with one monoterpene (3R,4R,6S)-3,6-dihydroxy-1-menthene (7), two triterpenes lupeol (8) and ursolic acid (9), and β-sitosterol (10). The structures of five new constituents (1 - 5) were elucidated by spectroscopic methods including 2D-NMR experiments. The compounds 1, 5 and 7 showed antibacterial activity by being assayed against Staphylococcus aureus, Bacillus subtilis and Escherichia coli.

Key words

Ligularia sagitta - Compositae - Eremophilenolides - Sesquiterpenes - antibacterial activity

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