Hypouricemic effect in hyperuricemic mice and xanthine oxidase inhibitory mechanism of dietary anthocyanins from purple sweet potato (Ipomoea batatas L.)

This study was aimed to investigate the hypouricemic effect of anthocyanins from purple sweet potato in vivo and their possible interaction mechanism to xanthine oxidase (XO) in vitro. In comparison with dosage of 100 mg kg(-1) anthocyanin-rich purple sweet potato extracts (APSPE), 25 mg kg(-1) double acylated anthocyanins from purple sweet potato (HAA-PSP) had greater ability to reduce uric acid level and inhibit the key enzymes in uric acid production pathway. In vitro experiments indicated that HAA-PSP might be the main active component in APSPE. HAA-PSP could effectively inhibit XO activity and possibly possessed a single binding site in XO, which was of higher affinity than that of LAA-PSP. Molecular docking was performed using Discovery Studio 2018 and the results showed that HAA-PSP could strongly bind to XO, and the interaction mechanism was the insertion of acyl group of anthocyanins into the hydrophobic region of XO by interacting with certain amino acid residues. In conclusion, HAA-PSP could be developed as a dietary supplement for hyperuricemia treatment.