Variation in Volatiles of Astragalus gombiformis Pomel

Astragalus, genus of Fabaceae, comprises more than 1500 species that are distributed in the Orient and North Africa (Ozenda, 1991). Many Astragalus species are toxic. In contrast, several therapeutic properties are assigned to other plants of this genus. In folk and modern medicine, Astragalus species such as Astragalus mongholicus Bunge and Astragalus membranaceus (Fisch) Bunge are used against various diseases and for cancer therapy (Rios and Waterman, 1997; Lei et al., 2003; Yesilada et al., 2005; Yin et al., 2006). In the last decades, many plant essential oils were studied to discover compounds of possible interest for medicinal and environmental applications due to their biological activities, such as fungicidal, antimicrobial, insecticidal, and antiproliferative effects against cancer cells (Conforti et al., 2009; Batish et al., 2008). To our knowledge, few studies related to essential oils of Astragalus species have been reported. Wild and cultivated Astragalus corniculatus contains essential oils that possess cytotoxic activity (Krasteva et al., 2008). The volatiles from Astragalus glycyphyllos, Astragalus hamosus, Astragalus cicer, and Astragalus spruneri, and their application for the chemotaxonomy were studied by Platikanov et al. (2005). In Tunisia, the fl ora contains many Astragalus species such as A. epiglottis L., A. sesameus L., A. baeticus L., and A. caprinus usually distributed in desert regions (Le Floc'h, 1983). Except the studies of Semmar et al. (2001, 2002, 2005) on Astragalus caprinus, no previous phytochemical investigations related to other Astragalus species of Tunisian fl ora have been reported. Astragalus gombiformis Pomel, taking recently the taxonomy of Astragalus gombo subsp. gomboeformis (Pomel) Ott, is a sort spread in the big oriental Erg of Tunisia under Saharan climate characterized by different stresses. This plant, presenting an important biomass, is moderately appetible by animals, probably for its toxicity or its rankness. The present study aims at investigating the chemical composition of volatile compounds from aerial parts of Astragalus gombiformis at different phenological phases.