Chemical Composition and Antimicrobial Activity of the Essential Oils of Two Aromatic Plants Cultivated in Morocco (Cinnamomum cassia and Origanum compactum)

The present study aims to evaluate the antibacterial properties of natural products according to a pharmacodynamic approach in order to propose them as alternatives to synthetic products. Two essential oils (Cinnamomum cassiaandOriganum compactum) were the subject of the chemical and biological study. First, we evaluated the sensitivity of the strains of avianSalmonellato the main antibiotics used and then to the chromatographic analysis of the composition of the two essential oils (EO); finally, we proceeded to thein vitroevaluation of the antibacterial activities of these EO (alone and in combination with antibiotics). The results obtained showed that carvacrol (35.2%), followed by gamma-terpinene (20.1%), was the main constituent of the essential oil ofO. compactumwhile cinnamaldehyde (69.1%) represents the major component of the essential oil ofC. cassia. The antibioresistance profile of theSalmonellatested showed resistance to ampicillin (35%) and oxytetracycline (41.3%). Active products extracted from the essential oils studied showed antibacterial activity againstSalmonellastrains.C. cassiaproducts were shown to be more active forSalmonella enteritidis(average inhibition diameter: 16.3 mm) and forSalmonella gallinarum(average inhibition diameter: 27.7 mm). The best synergistic activity with antibiotics has been obtained with the essential oil ofC. cassiaand its active product cinnamaldehyde. The minimum inhibitory concentration (MIC) of cinnamaldehyde is the lowest (0.05%). The results prove the presence of an antibacterial activity and a synergistic effect of two essential oils studied with the main antibiotics.