Susceptibility of Helicobacter pylori to essential oil of Dittrichia viscosa subsp. revoluta.

The essential oil of Dittrichia viscosa subsp. revoluta and its fractions were assessed for anti-Helicobacter activity. The essential oil was isolated by hydrodistillation, submitted to flash column chromatography and analysed by gas chromatography, gas-chromatography coupled to mass spectrometry and (13)C-nuclear magnetic resonance. The anti-Helicobacter activity was determined by incorporation of the crude essential oil and oxygenated fractions of the oil into the culture medium. At a concentration of 0.025 microL/mL no recovery was registered when one of the oxygenated fractions of the oil, mainly constituted by 3-methoxy cuminyl isobutyrate (about 40%), was used. This fraction revealed a higher activity against the six H. pylori strains tested when compared with the other oxygenated fractions. The crude essential oil at a concentration of 0.33 microL/mL reduced the initial population of H. pylori CCUG 15818 of 8.52 +/- 0.30 log(10) cfu/mL to 7.67 +/- 0.22 log(10) cfu/mL. The susceptibility of several Helicobacter pylori strains to the oxygenated fraction of Dittrichia viscosa subsp. revoluta essential oil suggests the possible use of these natural products in combating this widespread infection.