Extraction et caractérisation des huiles essentielles de six plantes provenant de l’ouest Algérien (Salviaargentea, Ammoidesverticillata, Saturejacandidissima Thymus fontanesii, Artemisia herbaalbaetRosmarinusofficinalis): Effet de synergisme ou d’antagonisme sur l’activité antioxydante et antimicrobienne

Abstract

tract The rich flora of Algeria is well established. Like other areas, western Algeria and in particular the region of Tlemcen is characterized by a flora particularly rich in medicinal plants. The preservation of this plant biomass is a crucial issue across the country. The work of this thesis focused on the study of chemical composition and activity: Ammoides verticillata, Satureja candidissima, Salvia argentea, Thymus fontanesii, Rosmarinus officinalis and Artemisia herba-alba. Extraction of EOs was carried out by hydrodistillation type clevenger and analyzed by CG and CG-MS. EO's roots of S. argentea was rich in ferruginol (19.5%), pulegone (17.9%), (E) -phytol (13.5%), 6.7 dihydroferruginol (11.3%) and abitatriene (10.0%); 9%). A. verticillata HE was dominated by carvacrol (44.3%), limonene (19.3%), p-cymene (19.2%) and γ-terpinene (11, 1%). While, the main components of S. candidissima EO were pulegone (70.4%), menthol (5.2%) and iso-menthone (4.5%). The EO of T. fantenezii was characterized by thymol (76.6%) and p-cymene (7.4%). The HE of A. herba-alba was dominated by camphor (30.2%) and chrysanthenone (24.3%). R. officinalis EO was characterized by presence of 1,8-cineole (15.4%), α-pinene (11%), borneol (12.7%), camphor (15%), and verbenone (10.7%). The antioxidant activity of the oils studied showed very promising antioxidant effects by the DPPH and FRAP methods. On the other hand, A. verticillata and S. argentea EOs had the highest antioxidant potency with IC50 values of 0.7 mg/ml and 0.4 mg/ml, respectively. While a synergistic antioxidant capacity was observed with the combination of A. verticillata and S. candidissima oils with an IC50 of 0.17 mg/ml which showed a capacity close to both synthetic antioxidants. The antimicrobial activity showed an inhibitory effect against several bacteria by the essential oils and the different fractions, individually or in combination with bactericidal and fungicidal effects. The most intense inhibitory effect was observed with S. argentea EO, which showed very good inhibitory effects against all strains including L. rhamnosus, B. cereus, B. subtilis and P. aeruginosa with MICs ranging from 0.02 to 0.8 mg / ml. On the other hand, the association of EO from T. fontanesii/S. argentea/R. officinalis significantly reduced MICs of E. coli and B. subtilis bacteria. Similarly, the combination of EOs of S. argentea/A. verticulata showed a very interesting antimicrobial activity against strains of S. Typhi, C. sporogenes and E. faecalis with very low MIC