Anti-Hyperuricemic Effect of Ethyl Acetate Sub-Fractions from Chrysanthemum morifolium Ramat. Dried Flowers on Potassium Oxonate-Induced Hyperuricemic Rats

Xanthine oxidase (XO) plays an important role in purine degradation in humans. The study aimed to determine the XO inhibitory potential of Chrysanthemum morifolium dried flower ethyl acetate sub-fractions and its anti-hyperuricemic effect in rat models. Bioassay-guided fractionation based on XO inhibitory assay was employed to obtain bioactive fractions and sub-fractions. In vitro cytotoxicity and cellular antioxidant capacity of the sub-fraction and its mode of XO inhibition were also investigated. The anti-hyperuricemic effect of the bioactive sub-fraction was investigated using rat models via oral consumption, and followed by an XO mRNA gene expression study. The compounds in the bioactive sub-fractions were identified putatively using HPLC-Q-TOF-MS/MS. Ethyl acetate (EtOAc) fraction exhibited the highest XO inhibition among the fractions. It was further fractionated into 15 sub-fractions. F10 exhibited high XO inhibitory activity, cellular pro-proliferative effect, and intracellular antioxidant activity among the sub-fractions tested. This sub-fraction was non-cytotoxic at 0.1-10 mu g/mL, and very effective in lowering serum and urine uric acid level in rat models upon oral consumption. A total of 26 known compounds were identified and seven unknown compounds were detected via HPLC-Q-TOF-MS/MS analysis. The possible mechanisms contributing to the anti-hyperuricemic effect were suggested to be the non-competitive inhibition of XO enzyme, XO gene expression down-regulation, and the enhancement of uric acid excretion.

Automated summary

This study found that the ethyl acetate sub-fractions of Chrysanthemum morifolium dried flowers have strong inhibitory activity against Xanthine oxidase (XO), and also have a certain therapeutic effect on hyperuricemia in rats. Further research revealed that the sub-fraction may exert its anti-hyperuricemic effect through non-competitive inhibition of XO enzyme, down-regulation of XO gene expression, and increased uric acid excretion.