DOI: 10.36347/sajp

Pages: 477-482

The chemical composition of essential oil, isolated from Urospermum dalechampii by hydrodistillation, was analysed by GC and GC/MS. A total 26 compounds representing 97.82% of the oil were identified in Amouchas population. This oil is Characterized by a high rate of palmitic acid (24.3%), henecosane (10.1%), 2-methyl-Z,Z-3,13- octadecadienol (7.1%), tricosane (6.73%), dill apiole (5.25%), myristic acid (4.8%), myristicin (4.7%), 2-pentadenanone- 6,10,14-trimethyl (4.4%), lauric acid (3.9%), elemicin (3.3%). Other major compounds are present in the essential oils of this species, isobutyl phlatate, caryophyllene oxide, epicubenol-1, β-guaiene, α-bisabolol and 3,7-dimethyl-octa-1,6- diene. To test the antibacterial activity of essential oil of U. dalechampii, eleven bacteria are used in this study. The oil showed a significant effect against Gram-negative bacteria, and modest antibacterial activity against Gram-positive bacteria. The population of U. dalechampii studied showed a diploid chromosome number with 2n = 2x = 14, and a basic chromosome number x = 7