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Antioxidative activity of an isoflavonoid, 2"-O-glycosylisovitexin isolated from green barley leaves

Kitta, K., Hagiwara, Y., Shibamoto, T.
Journal of agricultural and food chemistry 1992 v.40 no.10 pp. 1843-1845
Hordeum vulgare, flavonoids, leaves, antioxidants, oxidation, squalene, linoleic acid, malondialdehyde, lipid peroxidation, ultraviolet radiation, hydrogen peroxide
A flavonoid, 2''-O-glycosylisovitexin (2''-O-GIV), with antioxidative activity previously proved by the thiobarbituric acid method, was isolated from young green barley leaves. Antioxidative activity of 2''-O-GIV was determined by using gas chromatography to measure amounts of malonaldehyde (MA) formed from squalene and ethyl linoleate upon UV irradiation or with Fenton's reagent. 2''-O-GIV suppressed the formation of MA from squalene upon oxidation with Fenton's reagent 32% at the level of 150 micromolars/75 microliters of squalene. 2''-O-GRV decreased MA formation from ethyl linoleate upon UV irradiation to 40% at pH 7.4; no significant effect was observed at pH 3.5 and 11. 2''-O-GIV (100 micromolars) decreased MA formation from ethyl linoleate (10 microliters) with Fenton's reagent to 59% and 10% at pH 3.5 and 7.4, respectively. 2''-O-GIV showed antioxidative activities almost equal to that of alpha-tocopherol in all of the experiments.