Sesquiterpene lactones from Anthemis altissima and their anti-Helicobacter pylori activity.

Seven sesquiterpene lactones, (-) sivasinolide (1), a new naturally occurring eudesmanolide (altissin, 2), desacetyl-beta-cyclopyrethrosin (3), tatridin-A (4), 1-epi-tatridin B (5), 1alpha,10beta-epoxy-6-hydroxy-1,10H-inunolide (6), and spiciformin (7), were isolated from Anthemis altissima. Also isolated were 10 known flavonoids, namely, apigenin (8), kaempferol 4'-methyl ether (9), quercetin (10), quercetin 3-methyl ether (11), isorhamnetin (12), rhamnetin (13), 6-hydroxyquercetin 3,6,4'-trimethyl ether (14), isoquercetrin (15), taxifolin (16), and eriodictyol (17), and one phenolic acid, chlorogenic acid (18). The structure and the stereochemistry of compound 2 were deduced by spectroscopic methods. The in vitro activity of the sesquiterpene lactones (1-5) against Helicobacter pylori, as well as against three Gram-positive and three Gram-negative bacteria growing aerobically, was tested using the microdilution method. Compounds 8-18 have also been tested against H. pylori.