Abstract: In order to investigate the effect of anthocyanins from purple sweet potato on   cultivars ZA1 and JS6 were comparatively analyzed by HPLC and LC-MSn. The results indicated  that petunidin was exclusively contained in ZA1 compared to pelargonidin in JS6. Anthocyanins from both purple sweet potato cultivars had inhibitory effect on α-glucosidase activity. Anthocyanins from purple sweet potato cultivar ZA1 showed better anti-α-glucosidase activity with an inhibitory rate of more than 50% obtained after 15 min of reaction at 40 ℃ and 0.1 mg/mL 600 μL concentration (the ratio of anthocyanins weight to total reaction volume was 18%). The Lineweaver-Burk plot showed that anthocyanins from ZA1 inhibited α-glucosidase activity in a competitive pattern with a Ki of 5.43 × 10-2 mmol/L and  vmax of 1.71 μmol/(L·min).

Key words: purple sweet potato, anthocyanin, α-glucosidase activity, inhibition