Eremophilane-type sesquiterpene derivatives from Senecio aegyptius var. discoideus.

Investigation of a CH(2)Cl(2) extract of the aerial parts of Senecio aegyptius var. discoideus afforded nine eremophilane compounds, of which six are new (1-6), namely, 1beta-hydroxy-8alphaH-eremophil-7(11),9-dien-8beta,12-olide (1), 1beta,8alpha-dihydroxyeremophil-7(11),9-dien-8beta,12-olide (2), 1beta-hydroxy-8alpha-methoxyeremophil-7(11),9-dien-8beta,12-olide (3), 1-oxo-8alpha-methoxy-10alphaH-eremophil-7(11)-en-8beta,12-lactam (4), 1beta,10beta-epoxy-8alpha-hydroxyeremophil-7(11)-en-8beta,12-olide (5), and 1beta,10beta-epoxy-8alpha-methoxyeremophil-7(11)-en-8beta,12-olide (6). The structures of 1-6 were elucidated by spectroscopic methods and by comparison with literature data. The antibacterial activity of the isolated compounds was tested against Bacillus cereus and a Serratia sp.