Chemical Constituents and Antibacterial Activity of Essential Oils from Flowers and Stems of Ageratum conyzoides from Ivory Coast

The essential oils (EOs) obtained by hydro-distillation of flowers and stems of Ageratum conyzoides L. (Asteraceae) growing in Ivory Coast were investigated. The oils were analyzed and characterized by GC and GC MS. Analyses of the EOs led to the identification and quantification of 48 constituents in the flower oil and 44 from the stem oil, respectively. Characterization of the EOs revealed the predominance of 6-demethoxyageratochromene or precocene I (flower: 58.8%, stem: 76.5%) and the sesquiterpene beta-caryophyllene (flower: 15.2%, stem: 8.1%). Six of the identified compounds beta-copaene, hexanal, trans-cadina-1(6),4-diene, alpha-calacorene, caryophylla-4(12),8(13)-diene-5-beta-ol and 1,10-di-epi-cubenol are reported for the first time as constituents of A. conyzoides. Comparative analysis with data from Nigeria, Pakistan, Fiji and Brazil is reported. The antibacterial activity of EOs from of A. conyzoides was tested against seven bacteria. The inhibition zones and minimum inhibitory concentration (MIC) for bacteria strains which were sensitive to A. conyzoides EOs were in the range of 6.7 to 12.7 mm and 64 to 256 mu g/ml, respectively. The EOs showed moderate activity against Staphylococcus aureus and Enterococcus faecalis.