Determination of several active substances and antioxidant activities of different extracts of Vitis vinifera L. Red Seedless

The phenolic compounds content and antioxidant activity of selected vitis vinifera L. redseedless from Maragheh region, East Azerbaijan (Iran) was investigated with a view to theirexploitation as a potential source of natural antioxidants. Antioxidant activities of the sampleswere determined by three testing systems namely DPPH, β-carotene/linoleic acid, and reducingpower assays. In the DPPH system, the highest radical scavenging activity was seen by the polarsubfraction of the methanol extract in frozen fruits (IC50 = 26.34 ± 6.5 μg/ml). In order toevaluate the efficiency of different methods for the extraction of the main polyphenols in grape,two methods were tested and compared. Results showed that the maceration method is better thanthe ultrasonic. These advantages are visible on extracting of the flavonoids, anthocyanins, totalphenolic, ascorbic acid contents and antioxidant capacity.

Keywords:

total phenols , flavonoids , anthocyanin , ascorbic acid , antioxidant , Grape