Extraction and Antioxidant Activity of Phenolic Compounds from Okra Flowers

Purpose: To investigate the extraction and antioxidant activity of phenolic compounds from Okra flowers.
Methods: The phenolic compounds in Okra flowers was obtained by traditional solvent extraction method and determined by Folin-Ciocalteu (FC) method. The extraction was optimized using response surface methodology (RSM). The antioxidant activity of the obtained extract was determined by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and reducing power assays.
Results: The optimal extraction conditions were as follows: extraction time, 2.5 h; ethanol concentration, 59.16 %; extraction temperature, 73.91 °C; and liquid-solid ratio, 20 mL/g. The mean total phenolics yield under the optimum conditions was 40.77±0.83 mg GAE /g material, which is near the predicted value of 44.20 mg GAE /g material. The total phenolics of the extract was an effective scavenger in quenching DPPH radicals. A linear correlation between the concentration of the total phenolics extract and reducing power was observed with a correlation coefficient (r²) of 0.9973.
Conclusion: Using RSM, the extraction of total phenolics in okra flowers has been optimized. The extract exhibits a strong DPPH radical scavenging activity and reducing power, which makes it a potential functional ingredient in the food and pharmaceutical industries.

Keywords
Okra flowers; Extraction; Response surface methodology; Phenolics; Antioxidant