Antioxidant Potential and Inhibitory Effect of Essential Oil from the Aerial Parts of <i>Origanum vulgar</i>e L. Against Salmonella Poultry in Morocco

Abstract

Origanum vulgare L. is an aromatic plant well-known in traditional medicine and widely applied as a food additive due to its great antimicrobial potential. This study aims to investigate the chemical composition of the essential oil (EO) of O. vulgare L. using gas chromatography/mass spectroscopy (GC/MS) and evaluate their antioxidant and antibacterial activities against three strains of Salmonella from avian origin. The O. vulgare L. EO was extracted by hydrodistillation using the Clevenger apparatus and the different chemical compounds were identified using GC/MS. The antimicrobial activity was evaluated using the aromatogram method on agar and microdilution assay in 96-plates, also the antioxidant activity was carried out using four different tests: DPPH, ABTS•+, reducing power, and phosphomolybdate ammonium. Results of chemical composition showed that Carvacrol was the EO’s major compound with a yield of 50.2%. Through DPPH and ABTS•+, the antioxidant activity of the EO showed an IC50 of 5.75 ± 0.11 and 7.35 ± 0.30 mg/mL, respectively. The reducing power and the molybdate assay of EO presented an EC50 of 280.32 ± 8.63 and 275.37 ± 2.79 µg/ mL, respectively. The antibacterial activity revealed that the three strains of Salmonella exhibited a sensitivity with variable diameters ranging between 30 and 40 mm, the MIC values ranging from 12.5 to 50.0 µg/mL, and the MBC which varies between 100 and 200 µg/mL. The obtained results showed that the O. vulgare L. can be used to fight against multiresistant bacteria and can be a source of bioactive molecules given its antioxidant properties.