Combination Effects of Zataria multiflora, Laurus nobilis and Chamaemelum nobile Essences on Pathogenic E. coli and Determination of Optimum Formulation Using Fraction and Factorial Statistical Method

In this study, antibacterial combination effects of Zataria multiflora, Laurus nobilis and Chamaemelum nobile essences was examined and the optimum bactericide dosages of the combination was determined on E. coli PTCC1330.
Essence extraction was conducted using water distillation method from Z. multiflora, L. nobilis leafs and C. nobile capitals by Clevenger apparatus. The combination effects of the essences were studied on E. coli in different dosages using Qualitek-4 software and fraction of the full factorial statistical method. Essences interactions and the contribution of each essence were evaluated on inhibition of E. coli growth.
MIC values was determined for Z. multiflora, L. nobilis and C. nobile essences as 0.01, 0.1 and 0.05 mg ml-1, also MBC values was 0.1, 0.5 and 0.5 mg ml-1, respectively. Z. multiflora essence dosages showed the highest percentage of antibacterial effect (64. 2%) on E. coli, while the antibacterial effect was evaluated 13.54% and 6.89% for L. nobilis and C. nobile essences, respectively. In optimum conditions, all three essences dosages should be equal to 1 mg. mL-1 and the percentage of bacterial growth inhibition was determined by 72.76% whereas it has 81.8% consistency with real results at optimum conditions (60%). The maximum interaction was observed between Z. multiflora and C. nobile essences dosages with 33.44% severity index.
Z. multiflora essence had a considerable antibacterial effect on E. coli, while antibacterial properties of L. nobilis and C. nobile essences were evaluated as a weak effect.