New Weakly Cytotoxic Eremophilane Sesquiterpenes from the Roots of Ligularia virgaurea

Abstract

Six new eremophilane sesquiterpenes, including a novel nortrieremophilane carbon skeleton, were isolated from the roots of Ligularia virgaurea. Their structures were elucidated as 3α,4α-epoxy-6α-(2′-methylacryloyl)oxy-8α-methoxyeremophil-7(11)-en-8β,12-olide (1), 3α,4α-epoxy-6α-(2′-methylacryloyl)oxy-8α-ethoxyeremophil-7(11)-en-8β,12-olide (2), 1β,10β-epoxy-6β-(2′-methylacryloyl)oxy-8β-methoxyeremophil-7(11)-en-8α,12-olide (3), 1β,10β-epoxy-6β-angeloyloxy-8β-methoxyeremophil-7(11)-en-8α,12-olide (4), 6β-methoxyeremophil-7(11)-en-8β,12-olide (5), and 5β-angeloyloxy-3a,4,5,6,7,7a-hexahydro-3aβ-methyl-1H-indene-2,4β-dioic acid methyl ester (6) by spectral methods, including IR, HR-ESI-MS, 1D and 2D NMR techniques. All of compounds were evaluated for their in vitro cytotoxic activities against human hepatoma (SMMC-7721), human promyelocytic leukemia (HL-60), and human hepatocyte (L-02) cells.

Key words

Ligularia virgaurea - Compositae - eremophilane - sesquiterpenes - cytotoxic activity

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