Enlargement of the variances in amount and composition of anthocyanin pigments in sweetpotato storage roots and their effect on the differences in DPPH radical-scavenging activity

To investigate the effect of differences in anthocyanin composition on radical-scavenging activity in the purple-fleshed sweetpotato storage root, 124 sweetpotato clones with various compositions of anthocyanin were produced by crosses among superior sweetpotato genetic resources, and were analyzed for anthocyanin composition and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity (RSA). The highest content of anthocyanin among the clones was twofold higher than the content of cv. Ayamurasaki, which has been released for use in industrial pigment production in Japan. The range of variance in anthocyanin composition was very wide, as the ratio of peak areas of cyanidin-based anthocyanins to total anthocyanin peak areas ranged from 85.7% to 6.0%. The relationship between anthocyanin content and RSA was positively correlated. Correlation coefficients between RSA and the HPLC peak areas of cyanidin-based anthocyanins ranged from 0.606 to 0.687, whereas those of peonidin-based anthocyanins were 0.124–0.271. These results clearly demonstrated that cyanidin-based anthocyanins are closely related to DPPH RSA in sweetpotato storage roots.

Research highlights▶ 124 sweetpotato clones with various compositions of anthocyanin were produced. ▶ Cyanidin-based anthocyanins to total anthocyanins ranged from 85.7% to 6.0%. ▶ Radical-scavenging activity positively correlated to anthocyanin content. ▶ Cyanidin-based anthocyanins are more closely related to radical-scavenging activity.