Anti-Helicobacter pylori Compounds from Santalum album

Six new sesquiterpenes, (Z)-2β-hydroxy-14-hydro-β-santalol (1), (Z)-2α-hydroxy-albumol (2), 2R-(Z)-campherene-2,13-diol (3), (Z)-campherene-2β,13-diol (4), (Z)-7-hydroxynuciferol (5), and (Z)-1β-hydroxy-2-hydrolanceol (6), together with five known compounds, (Z)-α-santalol (7), (Z)-β-santalol (8), (Z)-lanceol (9), α-santaldiol (10), and β-santaldiol (11), were isolated from Santalum album, by using bioassay-guided fractionation for Helicobacter pylori. The structures were determined by extensive NMR studies. The absolute configuration of compound 3 was determined by a modified Mosher method. The crude extracts as well as the isolated compounds showed antibacterial activity against H. pylori. Especially, compounds 7 and 8 have strong anti-H. pylori activities against a clarithromycin-resistant strain (TS281) as well as other strains.