Investigation des extraits à activités pharmacologiques de quelques espèces qui poussent dans les zones arides et semi arides

Abstract

Five plants from two different regions (arid and semi-arid) were selected in this work: Pistacia atlantica and L. antineae from Biskra town and Thymus algeriensis algeriensis, Marrubium alysson and Jasminum fruticans of Batna town. First, an extraction of two species Lavandula antineae and Thymus algeriensis essential oils and a preparation of hydro-methanolic, ethyl acetate and n-butanol extracts were carried out from all the studied plants. Both essential oils were analyzed by GC / MS, the chromatographic profile showed a richness of L. antineae essential oil in hydrocarbon sesquiterpenes such as β-bisabolene while the essential oil of T. algeriensis was rich in oxygenated sesquiterpenes such as elemol. Subsequently, a phytochemical screening followed by an HPLC / UV analysis were performed on hydro-methanolic extract of the aerial part of the various plants, followed by the determination of the total phenol compounds, flavonoids and condensed tannins. Results from the phytochemical screening indicated the presence of several chemical families such as polyphenols, flavonoids, tannins and alkaloids. HPLC / UV analysis revealed the common existence of quercetin and catechin in all hydro-methanolic extracts. P. atlantica was noted by the highest levels of total phenolic compounds, flavonoids and condensed tannins. Then, the antioxidant effect of the hydro-methanolic extract was tested by various methods: free radical scavenging (DPPH and ABTS), iron reduction tests (FRAP test, phenanthroline method, Ferrozin method), copper reduction test (CUPRAC test) and β-carotene bleaching test. Various tests to evaluate the inhibitory power of the plants hydro-methanolic extract on enzymatic activity of acetylcholinesterase, butyrylcholinesterase, α-glucosidase and tyrosinase were used. Significant antioxidant activity was observed for all extracts especially P. atlantica and remarkable antidiabetic, anti-Alzheimer and anti-tyrosinase effects were recorded for most species. P. atlantica gave a significantly higher α-glucosidase inhibition than acarbose. A higher anti-butyrylcholinesterase effect than galantamine was recorded for hydro-methanolic extract of L. antineae. Both species M. alysson and J. fruticans are characterized by a tyrosinase inhibition more remarkable than kojic acid. The SPF determination test was performed by measuring the absorbances of hydro-methanolic extracts in a range of 290 to 320 every 5 nm, J. fruticans provided the highest SPF value. Finally, the agar diffusion technique was carried out to evaluate the antimicrobial activity of two extracts ethyl acetate (AcEth) and n-butanol (But) of our five plants on Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa and Candida albicans. ATCC 2071. Both AcEth and But extracts of different species provided modest antimicrobial potential for the microbes tested.