Anthocyanins are polyphenolic glycoside pigments widely distributed in the plant kingdom. Recently, along with health trend against aging, anthocyanins have attracted much attention as functional food factors that prevent life-style related diseases. To develop new stable anthocyanin materials, we elucidated a correlation between the structures and the functionalities of acylated anthocyanins with two or more aromatic acids in the plant materials such as a purple sweet potato storage root and a butterfly-pea flower. Of the functionalities, the antioxidative activity was evaluated on the basis of DPPH radical scavenging activity and lipid peroxidation inhibitory activity. It was demonstrated that aglycone and/or aromatic acids with free phenolic hydroxyl groups on neighboring positions and only aromatic acids at outer sides in polyacylated anthocyanin molecules (folded in solutions) were more effective for the antioxidative activity.