Rich extract on total polyphenols and antioxidant activity obtained by conventional and non-conventional methods from Ahmeur Bouamer grape seed

Conventional and non-conventional extraction methods were applied in the first time for the determination of total polyphenols from Ahmeur Bouamer, an anthoctonous variety grape seeds. Independently of the time and temperature, a positive effect of particle size parameter on maceration has been noted and relativly high concentrations in polyphenols for 500 μm (67.78 ± 0.46 mg GAE/gdm), 500-355 μm (90.95 ± 0.24 mg GAE/gdm) and 355-180 μm (114.82 ± 1.24 mg GAE/gdm) have been obtained. The higher value of yield was reached by the microwave extraction (37.74±0.32%), followed by the maceration (14.16±0.15%) and the ultrasound (6.70±0.25%). The appropriate extraction method to obtain a relatively strong antioxidant activity from seeds was the microwave with inhibition of 69.67±1.76 % and 78.05±2.05% of DPPH and ABTS+ free radicals, respectively.Keywords: Ahmeur Bouamer, extraction, grape seeds, total polyphenols, antioxidant activit

Développement d'un agent de contraste pour l'IRM combinant l'imagerie paraCEST et du fluor 19

peer reviewe

Comparison of MRI properties between multimeric DOTAGA and DO3A gadolinium-dendron conjugates

The inherent lack of sensitivity of MRI needs the development of new Gd contrast agents in order to extend 20Hz,37%, the application of this technique to cellular imaging. For this purpose, two multimeric MR contrast agents obtained by peptidic coupling between an amido amine dendron and GdDOTAGA chelates (premetalation strategy, G1-4GdDOTAGA) or DO3A derivatives which then were postmetalated (G1-4GdDO-3A) have been prepared. By comparison to the monomers, an increase of longitudinal relaxivity has been observed for both structures. Especially for G1-4GdDO-3A, a marked increase is observed between 20 and 60 MHz. This structure differs from G1-4GdDOTAGA by an increased rigidity due to the aromatic linker between each chelate and the organic framework. This has the effect of limiting local rotational movements, which has a positive impact on relaxivity

Development of a Bimodal ParaCEST-Fluorine MRI Contrast Agent

NANOPARTICULES D'OXYDE DE FER OU DE MANGANÈSE DENDRONISÉES POUR L'IRM - Fédération Wallonie Bruxelle