Chemotaxonomic and biological activities of Tunisian Eryngium species

The essential oils of six Tunisian Eryngium species obtained by hydrodistillation (Clevenger apparatus) were analyzed by coupled Gas Chromatography-Mass Spectrometry (GC-MS). Falcarinol (0.6 – 98%), terpenes mainly sesquiterpenes (11 – 66%), and mono- and di-terpenes (0.1 – 2.6%) as minor constituents, have been identified. The petroleum ether, dichloromethane and methanol extracts of aerial parts and roots of these species were tested against 36 bacteria and yeast using the microdilution assay and their cytotoxicity was evaluated. The petroleum ether extract of roots of E. triquetrum was the most active with an IC50 up to 0.07 mg/ml. Bio-guided fractionation of this extract was conducted and led to the isolation of seven compounds. Photoactivation[1] of the plant extracts has also been investigated and irradiation with UVA wavelengths results in a higher, light-enhanced, antimicrobial activity.