Etude phytochimique de deux espèces Crataegus azarolus L. (Rosaceae) et Dioscorea communis L. (Dioscoreaceae).

Abstract

This work is the subject of a phytochemical and biological study of two medicinal plants belonging to two different families. 1. Crataegus azarolus (L.), belonging to Rosaceae family: After maceration of the aerial parts of the plant Crataegus azarolus in a methanolic solution and extraction with solvents of increasing polarity, three extracts are obtained. The extracts are separated using chromatographic methods of separation and purification, to lead finally to pure compounds. Then, the GC-MS analysis of a fraction of the CHCl3 extract allowed us to identify five volatile compounds for the first time from this species by comparing their mass spectra with the literature (NIST database). From the AcOEt extract five compounds were isolated, where two acetylated flavonoid glycosids were identified for the first time from the species. From the n-BuOH extract, three flavonoid glycosides are separated by CC and TLC. Their structures are elucidated through spectroscopic analysis methods. The antioxidant activity of the extracts and compounds is evaluated using five different methods (DPPH, ABTS, CUPRAC, FRAP and β-carotene). 2. Dioscorea communis (L.) Caddick & Wilkin, belonging to Dioscoreaceae family: Also, after maceration of the rhizomes of Dioscorea communis in diethyl ether solvent. The Et2O extract obtained was separated by chromatographic techniques (CC, TLC) to finally result in several compounds, seven of which are identified by spectroscopic methods of analyzes (MS, IR, UV, 1D and 2D NMR), where three of them are identified for the first time from this species. Et2O, AcOEt Extracts and some isolated compounds have shown an antioxidant activity by using five different methods (DPPH, ABTS, CUPRAC, FRAP and β-Carrotene), also these extracts and compounds are tested for the first time against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. This study confirmed that the presence of OH groups on the phenanthrene skeleton is essential for its antioxidant and anticholinesterase activities.