COMPARATIVE STUDY OF THE ANTIBACTERIAL ACTIVITY OF CINNAMON AND ORIGAN ESSENTIAL OILS AND THEIR PRIMARYCOMPONENTS ON AVIAN ESCHERICHIA COLI STRAINS

The emergence of bacterial resistance to the usual antimicrobial agents is nowadays a major challenge in therapeutics for both humans and animals. As a result, the search for new antimicrobial agents has become a necessity. In this context, a great interest was focused on naturally occurring substances with antibacterial activity. The present study consists of evaluating the antibacterial activity of two essential oils (EO) from two aromatic and medicinal plants commonly used in humans in Morocco, namely, oregano (origanum vulgare) and cinnamon (Cinnamomum cassia), and their primarycomponents, carvacrol and cinnamaldehyde respectively, against antibiotic-resistantEscherichia coli strains of avian origin. Extraction of the EO was carried out by hydrodistillation, and their chemical analysis was carried out by gas chromatography (GC).The cinnamon EO is mainly composed of cinnamaldehyde (nearly 90%), followed by beta-caryophyllen (6.1%), cinnamyl acetate and eugenol with (2.75%) and (0.46%); carvacrol is the primary component of oregano EO (65.51%), followed by gamma-terpinene (11.49%), p-cymene (6.27%), thymol (4%) and borneol (3.58%). The aromatogram showed interesting antibacterial activity of EO and their active ingredients against the used bacterial strains. The diffusion method on agar medium showedthat EO of cinnamon was more active than oregano EO against E. colistrains, with mean inhibition zones of 25.8+4.5mm and 17+3.7 mm, respectively. The obtained MICs showed also that cinnamaldehyde was more potent than carvacrol, with average MICs of 0.039% and 0.106%, respectively.