The essential oil of Senecio graveolens (Compositae): chemical compositionand antimicrobial activity tests

The chemical composition of the essential oil obtained from Senecio graveol ens (Compositae) was analyzed by GLC-MS and the components identified were: isovaleraldehyde, alpha-pinene. alpha-phellandrene, alpha-terpinene, p-cym ene, sabinene, gamma-terpinene, 1-melhyl-4-isopropenylbenzene, terpinolene, terpinen-4-ol, piperitenone, alpha- and beta-eudesmol. The investigation b y the agar-well diffusion method of the antimicrobial activity of the essen tial oil proved that it has antibacterial effects on Micrococcus luteus ATC C 9341, oxacillin-sensitive and oxacillin-resistant Staphylococcus aureus, as well as antifungal effects on clinically isolated Candida albicans. The minimal inhibitory concentration (MIC) values for M. luteus, oxacillin-sens itive S. aureus and C. albicans were 8.73, 10.91 and 2.13 x 10(-2) mg/ml, r espectively. The antimicrobial activity related to known antibiotics was ca lculated. These results would be compatible with a potential concentration- dependent selectivity of antifungal effect of S. graveolens essential oil. Minimal bactericidal concentration (MBC) is above 87.3 mg/ml. Thus the MBC/ MIC ratio would be clearly higher than 1 (above 8), indicating a bacteriost atic effect of the essential oil. (C) 1999 Elsevier Science Ireland Ltd. Al l rights reserved.