0% were terpenoid. The main constituent was limonene (31.2%). Some nonterpenoid acetylenic compounds were also detected [13].In the present study the composition of CHIR99021 mw essential oils obtained from roots and herbs of Hungarian population of C. canadensis was analyzed, and the antimicrobial activities of the oils against human pathogenic bacteria and fungi were evaluated for the first time.2. Material and Methods2.1. Plant MaterialRoots (roots 1) and flowering shoots of Conyza canadensis were collected in Szeged (Hungary) in July 2009. Further sample from horseweed roots (roots 2) was gathered in Jakabsz��ll��s (Hungary) in September 2009. The comminuted plant materials were dried at room temperature. 85.5g of the shoots, 94.9g of the roots 1, and 50.45g of the roots 2 were used for the hydrodistillation.

Voucher specimens (No. 804 and 805) have been deposited at the Department of Pharmacognosy, University of Szeged.2.2. Isolation of the Essential OilThe dried flowering shoots and roots were cut off and were subjected to hydrodistillation for 2 hours, according to the method of Ph. Eur 6.0 [14]. The obtained essential oils were dried over anhydrous sodium sulphate, filtered, and stored at ?18��C. The yields were calculated on the basis of the dry weight of the plant materials. The compositions of the oils were studied by GC and GC-MS techniques.2.3. Gas ChromatographyThe GC analysis was carried out with an HP 5890 Series II gas chromatograph (FID), using a 30m �� 0.35mm �� 0.25��m HP-5 fused silica capillary column.

Brefeldin_A The temperature program was from 60��C to 210��C at 3��C min?1 and from 210��C to 250��C (2min hold) at 5��C min?1. The detector and injector temperature was 250��C, and the carrier gas was N2, with split sample introduction.2.4. Gas Chromatography-Mass SpectrometryGC-MS analysis was performed with a FINNIGAN GCQ ion trap bench-top mass spectrometer. All conditions were as above except that the carrier gas was He at a linear velocity of 31.9cmsec?1 and the capillary column was DB-5MS (30m �� 0.25mm �� 0.25��m). Positive ion electron ionization mode was used, with a mass range of 40�C400amu. The constituents were identified by comparing their Rts and Kovats indices with published MS data [15] and from computer library searches. The identification was further confirmed with the aid of authentic samples (Extrasynthese, Genay, France). Kovats indices were calculated mainly from the GC-MS analysis results [16].2.5. Bacteriostatic and Fungistatic ActivitiesBacterial strains: Enterococcus faecalis (ATCC29212), Staphylococcus aureus (ATCC25923), Streptococcus pyogenes (HNCMB80002) Gram-positive bacteria; Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853) Gram-negative bacteria.