Isolement et determination structurale de metabolites secondaires de plantes sahariennes

Abstract

The present work consisted on a phytochemical and biological study of the species Pituranthos battandieri Maire, Algerian variety from the Apiaceae family, endemic to the Algerian and Moroccan Sahara. To the best of our knowledge this species has never been studied before. This reason and the endemism of this rare species encouraged us to undertake this work in which we also reported the chemical composition of the essential oil of its aerial parts performed by GC and GC/MS analyses. Our experimentation allowed the separation and purification of 23 compounds through the use of various chromatographic techniques (CCM, CC). All these structures have been elucidated by the combination of spectroscopic methods mainly: (UV-Vis), 1D NMR (1H, 13C, DEPT), and 2D NMR (COSY, HSQC, HMBC, NOESY), We also used high resolution mass spectrometry methods (HR-EI-MS and HR-ESI-MS) and comparison with literature data. Among the isolated compounds, 13 coumarins from which 5 were new, 4 flavonoids, 2 steroids, 3 phenolic compounds and 1 reduced sugar. In addition, a biological valorization consisting in the evaluation of the antioxidant activity was carried out on the n-BuOH extract of the aerial parts of Pituranthos battandieri Maire. This study showed that this species has a biological efficiency. In this study we also carried out an antibacterial assay against some pathogenic organisms, the microbiological results showed that this butanolic extract did not show antibacterial activity. The GC-FID and GC/MS analyses of the essential oil of Pituranthos battandieri Maire showed that this oil is mainly composed of myrcene (8.9%), α- phellandrene (17.5%), α-terpinene (14%), o-cymene (11.6%), β-phellandrene (3.5%), cis-linalol oxide (furanide) (5.9%) and trans-β-caryophyllene (3.4%).