High tert-Butylperoxyl Radical Scavenging Activities of Sweet Potato Cultivars with Purple Flesh

The tert-butylperoxyl radical (t-BuOO·) scavenging activities of ethanol extracts of 21 sweet potato cultivars with several flesh colors were examined using a tert-butyl hydroperoxide (t-BuOOH)/hemin/luminol system. Among them, sweet potato cultivars with purple flesh, which contained anthocyanins, had the highest t-BuOO· scavenging activities. Those cultivars with purple flesh also had the highest antioxidative activities against lipid peroxidation induced by auto-oxidation of linoleic acid. Most of the sweet potato cultivars with white, white-yellow, yellow and orange flesh had low t-BuOO· scavenging and antioxidative activities; however, some of them had higher activities. In all sweet potato cultivars tested, the t-BuOO· scavenging activities became higher with an increase in the total phenolic content.