Kinetic Comparisons of Anthocyanin Reactivities towards 2,29-Azobis(2- amidinopropane) (AAPH) Radicals, Hydrogen Peroxide

preventive factors against many diseases. Polyphenols, including flavonoids for example, catechins from green tea, which have been reported to be one of the strongest radical scavengers of peroxynitrite and other radicals. Their pharmacokinetic behavior has also been extensively examined. It is therefore generally accepted that flavonoids are a major food sourced antioxidant. Anthocyanins are a kind of flavonoid widely distributed in colored fruits and vegetables such as eggplants, red cabbages, grapes and blueberries. As with other flavonoids, anthocyanins have been discussed in relation to a wide range of physiological functions such as improvement of vision, prevention of cancer and generally together with their antioxidant activity. For example, Noda et al. studied the hydroxyl radical and superoxide radical scavenging activities of nasunin using ESR-spin trapping methods and revealed that delphinidin, the aglycon of nasunin, chelates iron ions to prevent hydroxyl radical generation during the Fenton reaction. Whilst Tsuda et al. reported the antioxidant effects of cyanidin 3-Ob-D-glucopyranoside (Cy3G) both in vivo and in vitro. Several other studies indicate the potential antioxidant properties of anthocyanins, whilst the absorption and metabolic properties of anthocyanin have recently attracted much attention. However, only a few systematic studies have investigated the structure–activity relationship of anthocyanins in terms of their reactivity towards reactive oxygen species (ROS), possibly because there is limited availability of anthocyanin standards. In the present study, we simultaneously determined the reactivities towards ROS of twelve major anthocyanins present in a wild berry extract by capillary zone electrophoresis (CZE), and discussed the structure–reactivity relationship for anthocyanins towards 2,29-azobis(2-amidinopropane) dihydrochloride (AAPH) radicals, hydrogen peroxide (H2O2) and tert-buthylhydroperoxide (t-BuOOH).