THE TOTAL PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF ROSELLE (Hibiscus sabdariffa) EXTRACT

Introduction: Roselle (Hibiscus sabdariffa) is widely known for its benefits and medicinal properties. The aim of this study was to determine the total phenolic content (TPC) in H. sabdariffa extract, its antioxidant activity and relationship between TPC and its antioxidant scavenging capacity. Methods: The TPC value for each phenolic extract in free, bound soluble and bound insoluble was determined by using Folin-Ciocalteu assay. The antioxidant scavenging capacity was evaluated by using DPPH assay. Results: The results obtained in this study showed that bound soluble phenolic compound (7.63 + 0.28 mg GAE/g DW) had the highest TPC value than the free and insoluble phenolic compound extracts (2.78 + 0.20 mg GAE/g DW and 3.61 + 0.85 mg GAE/g DW, respectively) (p<0.05). As for the IC50 values, bound soluble extract exhibited the greatest value(0.62%) as compared to the free and bound insoluble phenolic extracts  (0.90% and 1.14%, respectively). A positive correlation (R2 = 0.956) between three fraction (free, soluble and insoluble) of TPC and antioxidant radical scavenging capacity (DPPH) was obtained.  Conclusion: It can be concluded that phenolic compound in H. sabdariffa extracts have an effect to the antioxidant scavenging capacity particularly in the bound soluble form. This finding proved that H. sabdariffa extract could be a good source of natural antioxidant for food, cosmetic and pharmaceutical industry.