Contribution à la connaissance du métabolisme secondaire de trois plantes de la famille des Astéracées.

Abstract

Nowadays, aromatic and medicinal plants are still the first reservoir of biologically active compounds, an inexhaustible source of raw materials, so the preservation of these plant organisms is a crucial issue across the country. This thesis work focused on the knowledge and enhancement of natural resources in Algeria, and more specifically, a phytochemical and biological study on the volatile fractions of the three species of the genus Centaurea (Centaurea acaulis, Centaurea pullata and Centaurea sulphurea) which are a potential source of bioactive secondary metabolites. For this, two major components were developed: the chemical component revealed that the chemical characterization of the aerial parts of the two species of the same genus C. acaulis and C. sulphurea is different, in fact, the majority constituents are limonene and τ- muurolol for C. acaulis, caryophyllene oxide and viridiflorol for C. sulphurea, on the other hand, the chemical characterization of the root parts showed the same dominant component: an aliphatic hydrocarbon, (Z,Z,Z)-heptadeca-1 ,8,11,14-tetraene, commonly referred to as aplotaxene. Moreover, the chemical composition of hexane extracts is different from essential oils, however, they are no exception since they show the predominance of the constituent aplotaxene. On the other hand, the biological component showed very promising results for both antioxidant and anti-inflammatory activities, in addition, moderate results vis-à-vis the antimicrobial and neuroprotective activities. In addition, an initiative work on the inhibition of antioxidant enzyme receptors (CAT, SOD, GPx) by two computational chemistry methods demonstrated that the compound (Z)-phytol was the best inhibitor and could be suggested as a potential new drug. Antioxidant. This research work was completed by a therapeutic application : the development of an anti-inflammatory gel for local application, following the interesting results obtained by the molecule.