CHEMICAL PROFILE AND BIOLOGICAL ACTIVITIES OF ESSENTIAL OILS FROM TWO MOROCCAN SPECIES, MENTHA PIPERITA L. AND THYMUS SATUREIOIDES COSS

A. Aljaiyasha*, A. Kasratib, C. Alaoui Jamalic and A. Abbadd

ABSTRACT

To contribute to the valorization of Moroccan aromatic and medicinal plants, the main objectives of this study were to compare the antioxidant, insecticidal and phytotoxic activities of essential oils extracted from the aerial parts of two species collected at the flowering stage namely Mentha piperita L. and Thymus satureioides Coss. Analysis of the chemical composition of essential oils obtained by steam distillation showed the dominance of linalool (53.0%) and linalyl acetate (34, 4%) for M. piperita, and carvacrol (23.7%), borneol (17.5%) for T. satureioides. The results of the antioxidant activity evaluated by the DPPH assay showed that the essential oils of T. satureioides presented the highest antioxidant capacity with EC50 values of 0.783 ± 0.003 mg/ml, respectively. Data from the insecticidal activity against adults of Tribolium castaneum and Tribolium confusum determined by contact toxicity tests using filter paper revealed that the essential oil of M. piperita showed the highest insecticidal efficiency with DL50 and DL90 values of 0.29 and 0.55 μl/cm2 for T. castaneum, and 0.54 and 1.9 μl/cm2 for T. confusum. This species also presented an important germination inhibition rate ranging from 20 to 95% for the seeds of radish (Raphanus sativus) and from 10 to 92.5% for the seeds of lucerne (Medicago sativa).

Keywords: essential oil, chemical composition, antioxidant activity, insecticidal activity, phyto-toxic activity.