Etude Chimique Et Biologique De Plantes Médicinales Algériennes

Résumé: The present work is devoted to the phytochemical and biological study of an endemic species of the septentrional Sahara Fagonia longispina Batt. (Zygophyllaceae) and the chemical composition and antioxidant activity study of fruit essential oil of Zizyphus lotus (L.) Desf. (Rhamnaceae). In a first part, the phytochemical investigation of the species F. longispina using different chromatographic methods (CC, TLC and HPLC) led to isolation and identification by different spectroscopic methods (1D and 2D, MS and UV) 18 compounds. Among these isolated compounds, a new monoterpene ∆-2-carene-6-ol-6-O-(2',6'-diacetyl)-β-D-glucopyranoside, together with four other monoterpenes, seven flavonoids, four phenolic derivatives and two sterol. Moreover, the in vitro free radical-scavenging activity of the all extracts has been investigated by DPPH test, which have demonstrated that ethyl acetate extract are good sources of antioxidant compounds. However, all extracts of F. longispina showed no substantial result compared to the antioxidant activity of ascorbic acid. In addition, the total phenolic and the flavonoids contents were measured using spectrophotometers methods, the results showed that the acetate extract has a high content compared to the other extracts. As for antibacterial activity study, showed that a high antibacterial effect of the ethyl acetate extract. In a second part, the chemical composition of fruit essential oil Z. lotus has been investigated by the GC-FID and GC-MS analysis, which led to identified 38 compounds. Fatty acids represented the major fraction (saturated and unsaturated compounds 67.8 and 11%, respectively), followed by hydrocarbons (10.8%) and sesquiterpenes (1.1%).These results were quite different from those obtained previously on the fixed oil of the fruit of this species from two samples from Algeria. The antioxidant property of this oil was evaluated using β-carotene bleaching method. The result indicated the potent antioxidant activity of essential oils from Z. lotus.

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