In vitro Effects of essential oil and alcoholic extract of Anise (Pimipinella anisum) on Escherichia coli and Staphylococcus aureus

In spite of the growing of food industry and the observance of the hygienic principles in production and processing of foodstuffs, as well as the strict criteria that have been put in food factories or slaughterhouses, a significant percentage of industrial and non-industrialized countries residents are affected by foodborne diseases. Therefore, it is absolutely necessary to find new compounds and methods to minimize the growth and activity of harmful microbes transmitted by foods. This study was conducted to evaluate the effects of different levels (9 serial dilutions) of Pimipinella anisum essential oil and alcohol extract (5 repetitions of each) on Escherichia coli and Staphylococcus aureus. Disk diffusion and agar well diffusion methods were applied. Anise essential oil at dilution of 1/32 g/ml and its alcoholic extract at dilutions 1/4, 1/8 and 1/16 g/ml, had the most antimicrobial effect on both bacteria. Generally, in both methods, the effect of essential oil and alcoholic extract on E. coli was higher than that of S. aureus. Minimum inhibitory concentration (MIC) and minimum inhibitory concentration (MBC) of Anise essential oil were 1/256 and 1/128 g/ml on Escherichia coli and Staphylococcus aureus, respectively. MIC for extract were 1/16 for both bacteria and MBCs for which were of 1/8 and 1/4 for E. coli and S.aureus, respectively. The results of this study revealed that the alcoholic extract of this medicinal herb and high concentrations of its essential oil show a good antimicrobial activity.