Xanthine oxidase inhibitors from the flowers of Chrysanthemum sinense

From the MeOH extract of the flowers of Chrysanthemum sinense, a new flavone glucoside, acacetin 7- O-(3- O-acetyl- beta- D-glucopyranoside), has been isolated together with 27 known compounds including Flavonoids, caffeoylquinic acid derivatives, phenolics, and a monoterpenoid glucoside. Their structures were elucidated on the basis of spectroscopic data. Compounds and displayed significant Xanthine Oxidase inhibitory activity in a concentration-dependent manner, and compounds and showed more potent inhibitory activity, with IC50 values ranging from 0.13 to 2.31 microM, than that of a positive control allopurinol (IC50=2.50 microM). The kinetic study indicated that and displayed competitive-type inhibition like that of allopurinol, while displayed a mixed-type inhibition.