Eremophilane sesquiterpenes from Ligularia macrophylla.
Wang Q, Mu Q, Shibano M, Morris-Natschke SL, Lee KH, Chen DF.
New eremophilane sesquiterpenes, 6beta-sarracinoyloxy-1beta,10beta-epoxy-furanoeremophilane (1), 6alpha-angeloyloxy-10betaH-furanoeremophil-1-one (2), 1alpha-hydroxy-9-deoxycacalol (3), and 1beta-hydroxy-11(R,S)-8-oxoeremophil-6,9-dien-12-al (4a+4b), together with five known sesquiterpenes (5-9) were isolated from the roots and rhizomes of Ligularia macrophylla. The structures were elucidated by spectroscopic methods including 2D NMR techniques, and the structure of 1 was confirmed by a single-crystal X-ray diffraction experiment. The compounds were also evaluated for cytotoxic activity against human lung carcinoma (A-549) and human breast adenocarcinoma (MCF-7) and were found to show only very weak cytotoxicity.