In vitro inhibition of rat monoamine oxidase by liquiritigenin and isoliquiritigenin isolated from Sinofranchetia chinensis  

串果藤中甘草素和异甘草素对大鼠单胺氧化酶的体外抑制作用(英文)

作　　者：潘宣[1,2] 孔令东[1,3] 张勇[1] 郑汉其[3] 

机构地区：[1]南京大学功能生物分子研究所国家医药生物技术重点实验室 [2]兰州医学院药学系,兰州730000 [3]香港中文大学生物化学系

出　　处：《Acta Pharmacologica Sinica》2000年第10期88-92,共5页中国药理学报（英文版）

基　　金：Project co-supportred by the National Natural Science Foundation of China (№ 39725033 and 39900189);Doctoral Project of High Education (№ 1999028419).

摘　　要：AIM:To study the inhibition of liquiritigenin (1) and isoliquiritigenin (2) isolated from Sinofranchetia chinen-sis on rat monoamine oxidase A and B (MAO A and B). METHODS:Rat brain mitochondrial fraction, prepared by differential centrifugation, was utilized as a source of MAO activity. MAO activity was determined radio-chemically with [14C] 5-hydroxytryptamine (5-HT) and [14C]p-phenylethylamine (B-PEA) used as MAO A or B specific radiolabled substrates, respectively. The Ki and KI values were obtained from Lineweaver-Burk plot using linear regression analysis. RESULTS:Liquiritigenin and isoliquiritigenin were found to be inhibitory against both MAO A and B in a dose-dependent manner. IC50 (95 % of confidence limits) of liquiritigenin and isoliquiritigenin were 32 (26- 36) and 13.9 (12.8-15.6) μmol/L for the inhibition of MAO A, and 104.6 (89.0-118.9) and 47.2 (39.5-54.5) μmol/L for that of MAO B, respectively. Lineweaver-Burk transformation of the MAO A inhibition data indicated that the inhibition was non-competitive for both liquiritigenin and isoliquiritigenin whereas their inhibition of MAO B was of mixed type. Regarding MAO A inhibition, the Ki values of liquiritigenin and isoliquiritigenin were 31.5 umol/ L and 14.3 μmol/L, respectively. As to the inhibitionof MAO B, the Ki and KI data for liquiritigenin were 164.7 and 15.2μmol/L, and those for isoliquiritigenin were 62.2 and 9.3μmol/L, respectively. CONCLUSION:Liquiritigenin and isoliquiritigen inhibited the activity of MAO A and B in rat brain mitochondria, and the latter was more active than the former.目的:研究串果藤中甘草素和异甘草素体外对单胺氧化酶A型和B型的抑制作用.方法:根据不同的离心速度制备大鼠全脑粗线粒体作为单胺氧化酶的酶源;分别以5-羟基[侧链-2-^(14)C]色胺肌酸硫酸盐([^(14)C]5-HT)和2-苯基[1-^(14)C]乙基胺盐酸盐([^(14)C]β-PEA)为单胺氧化酶A型和B型放射性底物,用液体闪烁技术,研究甘草素和异甘草素酶抑制作用和抑制类型.结果:甘草素和异甘草素对单胺氧化酶A型和B型均具有抑制作用,呈良好的量效关系,对单胺氧化酶A型的IC_(50)(95％的可信限)分别为32(26-36)μmol/L和13.9(12.8-15.6)μmol/L,对单胺氧化酶B型的IC_(50)值分别为104.6(89.0-118.9)μmol/L和47.2(39.5-54.5)μmol/L.酶抑制特征曲线显示甘草素和异甘草素对单胺氧化酶A型呈非竞争性抑制,K_i值分别为31.5μmol/L和14.3μmol/L,而对单胺氧化酶B型呈混合竞争性抑制,K_i值分别为164.7μmol/L和62.2μmol/L,K_I值分别为15.2μmol/L和9.3μmol/L.结论:甘草素和异甘草素体外对单胺氧化酶A型呈非竞争性抑制作用,对单胺氧化酶B型呈混合竞争性抑制作用.

关 键 词：LIQUIRITIGENIN ISOLIQUIRITIGENIN Sino-franchetia chinensis LARDIZABALACEAE monoamine oxi-dase 

分 类 号：R285[医药卫生—中药学]