.Analyses phytochimiques et évaluation des activités biologiques des extraits et des huiles essentielles de deux plantes Algériennes. Dirigé

Abstract

Medicinal plants have been used for centuries to heal, long before the discovery of modern medicine. With the progress of pharmacology, these plants have served as models for the synthesis of numerous drugs due to their availability in nature. A major part of current research focuses on the study of original antioxidant and anti-radical molecules of natural origin. In this regard, our work focuses on the phytochemical and biological study of two plants collected in Algeria: Spartium junceum of the Fabaceae family and Convolvulus tricolor of the Convolvulaceae family. Our study begins with the extraction of the essential oil from the flowers of Spartium junceum by hydrodistillation and hydroalcoholic maceration of the aerial parts of Convolvulus tricolor, followed by extraction with solvents of increasing polarity, resulting in three extracts (ethyl acetate, n-butanol and dichloromethane) of this species. The essential oil and extracts are then subjected to quantitative analyses of polyphenolic compounds as well as flavonoids and the evaluation of antioxidant activity by four methods (DPPH, ABTS, phenantroline, FRAP). Test results showed that the ethyl acetate and n-butanol extracts have strong antioxidant properties, unlike the essential oil, which showed low antioxidant activity. Furthermore, a study of antibacterial activity by the disk diffusion method demonstrated that the extracts with ethyl acetate and dichloromethane have powerful antibacterial properties against gram-positive strains, unlike the essential oil, which showed no antibacterial activity. Additionally, a study of antifungal activity demonstrated that all three extracts exhibit strong antifungal activity at low concentrations. Finally, GC-MS analysis of the essential oil of the S. junceum plant identified 46 compounds, representing 74.784% of the essential oil.