Antioxidant activity of phytoestrogenic isoflavones.Author: Ruiz-Larrea MB et al. Publication: Free Radic Res. 1997 Jan;26(1):63-70.
Many researchers believe their most beneficial components for women are called isoflavones which are related to the more common flavonoids found universally in plants. Flavonoids help regulate the growth of plants and protect them from stress and the damaging effects of ultraviolet radiation. In humans, isoflavones enhance the resistance of low density lipoproteins to oxidation.
The aim of this study was to determine the antioxidant activities of the phytoestrogenic isoflavones: genistin, daidzin and formon. The antioxidant activity of the isoflavones in aqueous phase was determined by means of the ABTS = (2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) assay and total antioxidant activity assay.
The results show that genistein has the highest reactivity in scavenging the radical, followed by daidzein. Formononetin displaying no antioxidant activity. This study demonstrates the importance of the single 4-hydroxyl group and the 5-7-dihydroxy structure in the antioxidant reactivity of the isoflavones. It can be concluded that genistein is the most potent antioxidant among the isoflavones studied.Dietary isoflavones: biological effects and relevance to human health. J Nutr. 1999 Mar;129(3):758S-767S