Evaluation de l’activité antioxydante des extraits de la betterave rouge

Abstract

The main objective of this study is to evaluate the antioxidant activity of aqueous, ethanolic and acetonic extracts of red beet (Beta vulgaris L.) by two different methods, DPPH and FRAP, after determining the content of produced in polyphenols and flavonoids by colorimetric assay with Folin-Ciocalteux and aluminum trichloride respectively. The chemical characterization of the extracts obtained by maceration for 72 hours at 4°C in different solvents shows that distilled water has the highest extraction yield, with 13%, in comparison with ethanol (11.6%) and acetone (4.6%). The colorimetric assay of polyphenols shows that the ethanolic extract has the best polyphenol content with a concentration of 5.07mg/g of DM compared to the acetone extract (3.63 mg/g of DM) and the aqueous extract (1.25mg/g DM). The same result was also observed with the colorimetric assay of flavonoids with a concentration of 1.00 mgEQ/g in ethanol, followed by 0.27mgEQ/g in acetone and 0.060mgEQ/g for the aqueous extract. The study of the antioxidant activity by the DPPH and FRAP test demonstrated that the lowest value of the IC50 is obtained with the ethanolic extract, followed closely by the acetone extract and far by the aqueous extract, but which still remain quite high compared to the controls.