ABSTRACT
Aims: The ethanolic extract of Excoecaria agallocha stem bark was evaluated for antioxidant properties and quantification of bioactive polyphenols by HPLC-DAD. Methodology: ABTS assay, total antioxidant capacity, reducing power, total phenolic and flavonoid contents were used for determining antioxidant activities. Results: In ABTS assay, the extract showed 74.11% inhibition at 10 μg/ml and IC50 of 4.80 μg/ml, which was significant compared to ascorbic acid (12.20 μg/ml). The antioxidant capacity was calculated as 686 mg of ascorbic acid/g of extract. The maximum absorbance for reducing power assay was 0.73 at 250 μg/ml. The total phenolic and flavonoid contents were found to be significant (375.46 mg/g of gallic acid, 22.44 mg/g of quercetin equivalent, respectively). In HPLC assay, catechin hydrate had the highest content (713.91 mg/100 g of dry extract). Conclusion: The obtained results suggest the antioxidant activities with high concentration of catechin hydrate in the extract of Excoecaria agallocha stem bark.