Abstract

This study investigates antioxidant activity of Cassia fistula seeds extract. The antioxidant potential of this extract was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and xanthine oxidase inhibition assay. The IC₅₀ values were calculated for DPPH and xanthine oxidase assays in order to evaluate the antioxidant efficiency of C. fistula seed extract. Total phenolic and flavonoid content were also determined. The seeds extract were exhibit antioxidant activity 59.587% with an IC₅₀ value of 11.07 mg/ml in DPPH radical scavenging method. Furthermore, the C. fistula seeds extracts scavenged the superoxide radical generated by the xanthine/xanthine oxidase system. The percentage of xanthine oxidase inhibition activity of seed extract and allopurinol was 64.56 and 93.24%, respectively. The amount of total phenolic and flavonoid content was 474.25 ± 25.89 µg GAE/mg extract and 70.86 ± 1.43 µg catechin/mg extract respectively. High performance thin layer chromatography (HPTLC) screening indicates the presence of both free radical scavenging and phenolic compounds in C. fistula seed extract. The colored bands developed on TLC chromatogram visualized after spraying the plates with Folin-Ciocalteu’s and DPPH reagents which represent phenolic and radical scavenging compounds, respectively.

Key words: Cassia fistula seed, antioxidant activity, xanthine oxidase inhibition, phenolic compounds.