Comprehensive Evaluation of Antioxidant Activity of Ribes berry Fruit Species: A Chemometric Approach

Currant fruit extracts were characterized by (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, 2,2-azinobis-3 ethyl benzothiazoline-6-sulfonic acid cation decolorization activity, total reducing power, cupric ion reducing antioxidant power, and ferric ion reducing antioxidant power (FRAP) assays to evaluate their antioxidant activity. All five antioxidant assays revealed the highest antioxidant activity to be present for the black currants. The highest concentrations of phenolics were present in the black currants (1690 +/- 10mg gallic acid equivalents (GAE)/100g fresh weight), while the lowest value was obtained in the white currants (579 +/- 5mg GAE/100g fresh weight). The correlation between the total phenolic content and antioxidant activity assays was evaluated using regression analysis. A significant positive correlation was obtained between the total phenols and the cupric ion reducing antioxidant power (r=0.97, p<0.05), followed by that between the total phenols and FRAP (r=0.93, p<0.05). Hierarchical cluster analysis separated these selected fruit species into two statistically significant clusters with black currants as a distinctive cluster.