Séparation et Détermination Structurale de Métabolites Secondaires de deux Plantes Algériennes - Activités Biologiques

Abstract

This work is devoted to the phytochemical study of two plants, Thymelaea microphylla Coss. et Dur. and linaria aegyptiaca. belonging to the family Thymelaeaceae and scrophulariaceae respectively. These two families are known for their richness in various secondary metabolites. The objective of this work is the determination of the structures of molecules isolated from these plants, and the evaluation of the antioxidant activity of the major product (tiliroside) which was isolated from the ethyl acetate phase of Thymelaea microphylla extract and plant extracts of this plant. Several chromatographic methods were used in our experimental work which allowed us to isolate thirteen products from polar and semi polar phases of Thymelaea microphylla Coss. et Dur. extracts among which seven were identified and fully described. The phytochemical study of linaria aegyptiaca, allowed us to isolate ten products.The structures of seven were identified and fully described. All these structures were described for the first time for the two species. The methodology of purification was essentially based on the combination of different solid-liquid chromatographic methods on different media (thin layer chromatography (TLC), chromatography on silica column, high performance liquid chromatography (HPLC)). The structural determination of the isolated secondary metabolites was carried out thanks to the use of physicochemical and spectroscopic techniques including ultraviolet spectroscopy (UV), mass spectroscopy (MS) and magnetic resonance spectroscopy (NMR). For NMR spectroscopy, the dimensional techniques (1H, 13C, DEPT, J mod) and twodimensional (COSY, HSQC, HMBC) which we used, we were able to realize the final structure determination and unequivocal most secondary metabolites isolated. From a biological point of view, the various extracts Thymelaea microphylla have an average antioxydante activity.the chloroform extract can be considered a major antioxidant and study can be deepened for therapeutic applications.