Composition and Antimicrobial Activity of the Essential Oils ofThymus broussonettii, T. zygisandT. satureioides

Abstract

The essential oils of Thymus broussonettii, T. zygis andT. satureioides, which were produced from plants collected in Morocco, were analyzed by GC. The oil of T. broussonettii was found to be rich in carvacrol (53.3%), p-cymene (13.5%) and α-pinene (8.6%). The abundant compounds in T. zygis oil were p-cymene (50.6%), carvacrol (8.1%), borneol (5.8%), camphene (5.4%), α-pinene (5.2%) and thymol (5%), while the oil of T. satureioides contained borneol (31.2%), camphene (27.4%), α-pinene (17.5%) and linalool (6.3%) as major components. Examination of the antimicrobial activity of the oils against three bacteria, two yeasts and two molds revealed that the oil of T. broussonettii was the most efficient in both killing the microorganisms and inhibiting their growth. The other two oils were much less active even though T. zygis oil possessed slightly more antimicrobial activity than T. satureioides oil. Among the bacteria examined Escherichia coli was more resistant than Staphylococcus aureus and Bacillus megaterium both in growth inhibition and destruction trials. S. aureus was more resistant than B. megaterium to the inhibitory effect, but more sensitive to the lethal activity of the oils. The two yeasts Saccharomyces cerevisiae and Candida albicans were identical in their sensitivity towards the three oils, while the mold Zygorrhynchus sp. was more sensitive than Aspergillus niger to growth inhibition and destruction. To growth inhibition, the molds were more sensitive than the yeasts and the bacteria, but A. niger was shown to be more difficult to destroy than the most resistant bacterium E. coli.