Activités biologiques des extraits aqueux de Marrubium deserti récoltée dans deux régions (Ghardaïa et Djanet)

Abstract

This study is registered in the framework of research a new source of natural antioxidants and effective inhibitors of digestive enzymes, in particular α-amylase. For this purpose, the antioxidant power and the inhibitory activity of α-amylase are evaluated for the various aqueous extracts of the aerial part of M. deserti obtained according to the traditional methods of preparation (decoction and infusion). The plant is harvested in two different regions (Ghardaïa and Djanet). Quantification of total polyphenols and certain classes of phenolic compounds (flavonoids, acid phenols and condensed tannins) is carried out by colorimetric methods. The results obtained showed that the decoction of M. deserti from the Djanet region had the highest levels of total polyphenols, flavonoids, phenol acids and condensed tannins, which were of the order of 294,42 mg EAG/g, 20,73 mg ER/g, 8 mg EAC/g and 17,35 mg EC/g respectively. Evaluation of the antioxidant activity is carried out by three different methods, namely: ABTS, DPPH and FRAP. The most important anti-radical effect of ABTS is obtained with the infusion of M. deserti from the region of Ghardaïa which is of the order of IC50 = 0,22 mg /ml. These results remain low in comparison with the standard antioxidant Trolox, which has an IC50 equal to 0,10 mg / ml. As regards the inhibitory activity of α-amylase, the various aqueous extracts of M. deserti have a very remarkable ability to inhibit α-amylase. The most important IC50 is recorded for the M. deserti decoction of the Djanet region, which is on the order of 0,011mg/ml. These results confirmed the traditional use of this plant to treat diabetes.