Involvement of Anthocyanins and other Phenolic Compounds in Radical‐Scavenging Activity of Purple‐Fleshed Sweet Potato Cultivars

ABSTRACT: The 80% ethanol extracts of 5 purple‐fleshed sweet potato cultivars were separated into 2 fractions, anthocyanins‐ and phenolic compounds‐rich fractions, to clarify the contribution of these constituents to the radical‐scavenging activity. The separation was accomplished with an ethyl acetate liquid/liquid extraction. 1,1‐Diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activity in each fraction and the contributors varied according to the cultivars. The dominant DPPH radical‐scavengers in “Ayamurasaki” and “Kyushu‐132” were anthocyanins rather than phenolic compounds, while those in “Miyanou‐36” and “Bise” were phenolic compounds, such as chlorogenic acid. Furthermore, the high‐performance liquid chromatography analysis of anthocyanins showed that “Ayamurasaki” and “Kyushu‐132” were rich in anthocyanins with peonidin aglycon, whereas “Miyanou‐36,”“Bise,” and “Tanegashimamurasaki” contained cyanidin aglycon.