EXTRACTION AND PHYSICO-CHEMICAL AND BIOLOGICAL CHARACTERIZATION OF ESSENTIAL OILS FROM Cymbopogon schoenanthus IN THE REGION OF GHARDAÏA

Abstract

The aims of this work to study some physic-chemical parameters of essential oils (EOs) extracted from Cymbopogon schoenanthus, such as organoleptic properties, pH, density, refractive index and miscibility with ethanol ... etc. In addition, the study of biological activity devoted to antioxidant activity using DPPH and antibacterial activity in order to know the effectiveness of essential oils on some pathogenic bacterial strains, such as Escherichia coli ATCC 25922, Pseudomonas aeruginosa 27853, Klebsiella pneumoniae ATCC 700603, Salmonella enterica CIP 81-3 and Listeria innocua CLIP 74915. The extraction yield of essential oils is approximately 2% and has a liquid appearance, white yellow color and pink odor. Furthermore, the physical properties, we find the pH equal to 7.4, the estimated density is 0.8575, the refractive index is 1.482, and the miscibility with ethanol estimated at 1V / 3.2. That is to say, our EOs are basic and soluble. Regarding to the chemical analyzes, we find that the estimated acid number is 1.12, the ester number is 12.9, the iodine number is 0.14 and the saponification number is 14.25. Which means that essential oils have a small amount of free acids with a low ester index? The results of the antioxidant activity of these oils confirm that their estimated IC50 value is equal to 13.79 mg / ml and 0.03 mg / ml for ascorbic acid. This indicates that the antioxidant activity of ascorbic acid is much stronger than the essential oil analyzed. Also for antibacterial activity, these oils influence the inhibition with respect to all the bacterial strains used at the 100% concentration and the maximum inhibitory effect was 17.2mm against the bacterial strain Pseudomonas aeruginosa