Inhibition of xathine oxidase by rosmarinic acid / 第二军医大学学报

Objective:To study the inhibitory effect of rosmarinic acid on xanthine oxidase.Methods: Xanthine oxidase((0.1 U/ml)) was incubated with xanthine(1 mmol/L for determining formation of uric acid;50 ?mol/L for determining superoxide anions) in the presence of 20,40 and 60 ?g/ml rosmarinic acid or allopurinol as positive control.The formation of uric acid was determined by automatic biochemical analyzer 5 min after reaction and the production of superoxide anions was measured by Nitro Blue Btetrazolium(NBT) reduction.HL-60 cells(1 ml,2?10~(5)/ml) were pretreated with xanthine(100 ?l,6 mol/L) and xanthine oxidase(100 ?l,0.1 U/ml),then rosmarinic acid(500 ?g/ml) or allopurinol(1 ?g/ml,as positive control)(AnnexinⅤ-PI kit) was added to determine the cell apoptosis rate.HL-60 cells(1 ml,2?10~(5)/ml) were also pretreated with xanthine(100 ?l,6 mol/L) and xanthine oxidase(100 ?l,0.1 U/ml),then rosmarinic acid(500 ?g/ml) or SOD(100 U/ml,as positive control)(cell cycle method) was added to determine the cell apoptosis rate.Results: Rosmarinic acid obviously inhibited the production of uric acid and superoxide anion-induced reaction in NBT assay,with their IC_(50)being 56 ?g/ml and 21 ?g/ml,respectively.The rates of apoptosis inhibition by rosmarinic acid were both over 40% by Annexin Ⅴ-PI kit and cell cycle method.Conclusion: Rosmarinic acid is a competitive inhibitor of xanthine oxidase.

Inhibition of xathine oxidase by renierol extracted from South China Sea sponge / 第二军医大学学报

Objective:To study the inhibition of xanthine oxidase by renierol extracted from South China Sea sponge and study the influence of renierol on hyperuricemia in mice.Methods: After extracted from South China Sea sponge,renierol(20,40,60 ?g/ml) was added to a system containing xanthine oxidase(0.1 ?/ml) and xanthine(50 ?mol/ml);allopurinol((1 ?g/ml))was also addded to the system as positive control.The 5 min-fomation of superoxide anions was used to determine the activity of xanthine oxidase(Nitro Blue Btetrazolium reduction).Renierol(20,40,60 ?g/ml) was added to 25℃ pre-heated pyrogallol autoxidation to observe its eliminating effect on free radicals through determining the absorbance rate at 420 nm wavelength.Potassium oxonate,a uricase inhibitor,was used to induce hyperuricemia in mice and the mice were then treated with oral renierol(10,20,30 mg?kg~(-1)) or allopurinol(2 mg/kg) as positive control.The decrease of serum uric acid induced by renierol was determined by automatic biochemical analyzer.Results: Renierol was demonstrated to be a competitive inhibitor of xanthine oxidase in vitro,with its IC_(50) value being 1.36 ?g?ml~(-1).It also decreased uric acid in vivo.Conclusion: Renierol can decrease serum uric acid through inhibiting the xanthine oxidase.