Sheu S Y, Lai C H, Chiang H C
School of Pharmacy, Taipei Medical College, Taiwan, ROC.
Anticancer Res. 1998 Jan-Feb;18(1A):263-7.
Thirteen phenolic compounds were tested for their inhibitory effects on xanthine oxidase. The enzyme xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and of xanthine to uric acid, which has lambda max of 295 nm, forming the basis for a spectrophotometric assay of the activity of xanthine oxidase. The results showed that purpurogallin and silymarin group displayed the inhibitory effects on xanthine oxidase (IC50 = 2.96 +/- 0.12 and 27.58 +/- 3.48 microM, respectively). Their apparent inhibition constants (Ki) were 1.16 and 5.85 microM, and induced uncompetitive and mixed type (non-competitive-uncompetitive) inhibitions respectively, with respect to the substrate xanthine.
测试了13种酚类化合物对黄嘌呤氧化酶的抑制作用。黄嘌呤氧化酶催化次黄嘌呤氧化为黄嘌呤以及黄嘌呤氧化为尿酸，尿酸在295nm处有最大吸收波长，这构成了分光光度法测定黄嘌呤氧化酶活性的基础。结果表明，紫铆因和水飞蓟宾组对黄嘌呤氧化酶有抑制作用（IC50分别为2.96±0.12和27.58±3.48μM）。它们的表观抑制常数（Ki）分别为1.16和5.85μM，相对于底物黄嘌呤分别诱导非竞争性抑制和混合型（非竞争性-非竞争性）抑制。
