Chemical Indices and Antibacterial Properties of Some Essential Oils of Apiaceae and Lauraceae Spices in Southwest of Algeria

Abstract

This study is a part of the valorization of extract from three most commonly used Algerian spices, namely; caraway and cumin seeds and cinnamon bark. On the one hand, it aims at characterizing the chemical indices of extracted essential oils and evaluating the antibacterial activity of each essential oil by titration and disc diffusion method respectively. On the other hand, it attempts at evaluating the combined action of essential oils against four reference pathogenic bacterial strains, namely Escherichiacoli, Pseudomonasaeruginosa, Staphylococcus aureus, and Enterococcus faecalis by well and Chabbert-type diffusion method. The essential oils obtained by the hydrodistillation method have a relatively average extraction about 1.43, 2.3 and 2.5%, respectively for caraway, cumin, and cinnamon. The acid index indicates the behavior and amount of free acids present in the essential oil, in which the acid and saponification indices of cinnamon essential oil indicate a value of 4.48 and 168.56 respectively. It can also inform us about the susceptibility of the oil to undergo alterations. The antibacterial activity results showed that cinnamon essential oil (EO) proved to be the most active against the tested bacterial strains; caraway EO was active against Enterococcus faecalis, and the antibacterial action of cumin EO was the lowest. However, the association of the extracted essential oils has a higher synergistic effect than the independent effect of each essential oil, in which the MIC value found was estimated at 10 to 20 (V/V), 40 to 50 (V/V) and 50 to 70 (V/V) respectively for cinnamon, cumin and caraway. The obtained results show that the response to the antibacterial activity varies according to the plant species used and the extract tested alone or in combination.