THE STUDY OF POLYPHENOLIC COMPOUNDS PROFILE AND ANTIOXIDANT ACTIVITY OF VITIS VINIFERA L. LEAVES FROM WESTERN REGIONS OF ALGERIA

Polyphenols are secondary metabolites found in all vascular plants. Red grapes are one of these plants rich in these substances. The main objective of this study was to trace the polyphenolic compounds profile of red grape leaves from various Western regions of Algeria and to study their antioxidant activity. A spectrophotometric assay of the main phenolic groups and a chromatographic assay by HPLC-DAD and HPLC-FLU were carried out. The screening of anti-oxidant power was also performed by phosphomolybdenum method and DPPH assay. The results showed that all the studied leaves samples are rich in phenolic compounds with differences from one region to another. Polyphenol contents varied from ± 246 ± 18.93 to 923 ± 88.06 mg Eq gallic acid/g.dw. The HPLC assay identified the polyphenolic compounds profile of the studied samples. The antioxidant activity was widely covered and highlighted; the leaves extract of Aïn Temouchent sample is the most active with an EC₅₀ in the DPPH test of 0.08 mg/mL, which is higher than EC₅₀ of ascorbic acid. This work helped to trace the polyphenolic compounds profile of Algerian red grape leaves and allowed to valorize this plant by highlighting their antioxidant properties.