[Xanthine oxidase inhibitory activity and hypouricemia effect of propolis in rats].

The xanthine oxidase (XOD) inhibitory activity of propolis from China and Brazil was measured. The propolis from both place were seen to have XOD inhibitory activity. However, a stronger tendency was shown in the propolis from China. The compounds in each the propolis were measured quantitatively. A great deal of chrysin, galangin, and caffeic acid phenetyl ester were found in the propolis from China, an abundance of p-coumaric acid and artepillin C in the propolis from Brazil. Therefore it was revealed that the propolis compounds are very different depending on their place of origin. The XOD inhibitory activity of these five compounds was measured. Caffeic acid phenetyl ester had the strongest activity, with chrysin and galangin next; p-coumaric acid and artepillin C showed weak XOD inhibitory activity. We evaluated the hypouricemic effect of propolis from China on hyperuricemia induced by the uricase inhibitor, oxonic acid (500 mg/kg p.o., 1 h before the test drugs), and measured plasma uric acid values in rats. Oral propolis had a hypouricemic effect 2 h after its administration to oxonate-pretreated rats. These results suggested that a continuous intake of propolis may be effective for the prevention and the treatment of gout and hyperuricemia.