Antioxidant Properties and HPLC Assay of Bioactive Polyphenols of the Ethanol Extract of Excoecaria agallocha Stem Bark Growing in Bangladesh
Ismet Ara Jahan
BCSIR Laboratories, Dhaka, Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-E-Khuda Road, Dhaka-1205, Bangladesh.
Hemayet Hossain *
BCSIR Laboratories, Dhaka, Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-E-Khuda Road, Dhaka-1205, Bangladesh.
Proity Nayeeb Akbar
BCSIR Laboratories, Dhaka, Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-E-Khuda Road, Dhaka-1205, Bangladesh.
Md. Mahfuzur Rahman
Institute of Food Science and Technology, Dhaka, Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-E-Khuda Road, Dhaka-1205, Bangladesh.
Tanzir Ahmed Khan
Institute of Food Science and Technology, Dhaka, Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-E-Khuda Road, Dhaka-1205, Bangladesh.
Shaikh Emdadur Rahman
Pharmacy Discipline, Life Science School, Khulna University, Khulna-9208, Bangladesh.
Md. Afjalus Siraj
Pharmacy Discipline, Life Science School, Khulna University, Khulna-9208, Bangladesh.
*Author to whom correspondence should be addressed.
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.
Keywords: Excoecaria agallocha, total antioxidant capacity, catechin hydrate, vanillic acid.