Comparative study of the anti-oxidant activity of the total polyphenols extracted from Hibiscus Sabdariffa L., Glycine max L. Merr., yellow tea and red wine through reaction with DPPH free radicals

The present study is part of the evaluation of extracts of Glycine max L. Merr and Hibiscus L. Sabdariffa as antioxidants. A comparative study was performed with extracts of yellow tea and commercial red wine, two foods known for their antioxidant activity. The method applied is free radical scavenging using the 1,1-diphenyl-2-picrylhydrazyl (DPPH°). The antioxidant properties were identified and measured by the determining the anti-radical activity reducing index, expressed in percentage % RSA (Radical Scavenger Activity), and by the determination of the colouring intensity (IC50). All results are compared to those of ascorbic acid as reference antioxidant. The results indicate the following order for the antioxidant power of the extracts tested. % RSA (tea) > % RSA (Glycine max) % > RSA (red wine) % > RSA (Sabdariffa Hibiscus), and colouring intensities (IC50) ranging from 4.62 μM (ascorbic acid) to 1.10 μM (Hibiscus sabdariffa) correlated with their chemical structure and the content of phenolic compounds.