右旋黄皮酰胺在大鼠肝微粒体中的代谢转化

目的：研究黄皮酰胺的主要代谢途径,为进一步研究黄皮酰胺代谢的立体选择性打下基础。方法：用大鼠肝微粒体体外温孵法对右旋黄皮酰胺((+)-clausenamide)进行温孵,用硅胶柱色谱、制备TLC分离纯化代谢产物并通过光谱分析鉴定其结构。结果：分离得到5个代谢产物CM1,CM3,CM4,CM5及CM6,其结构分别鉴定为6-羟基,4-羟基,4,6-二羟基,4-苯环邻位羟基,4,7-苯环间位-二羟基黄皮酰胺。结论：黄皮酰胺的代谢主要发生羟化或双羟化,CM3是其主要代谢产物,量较少的CM4,CM6为其进一步代谢产生的双羟基代谢产物;另2个代谢产物CM1,CM5产生的量也较少;CM2未分离得到,但通过HPLC分析知其为右旋黄皮酰胺的微量代谢产物。     

左旋黄皮酰胺在大鼠肝微粒体中的代谢转化研究

用大鼠肝微粒体体外温孵法进行了左旋黄皮酰胺[(-)-clausenamide]代谢转化研究,优化了温孵体系,建立了反相HPLC-DAD同时分离检测左旋黄皮酰胺及其体外代谢产物的分析方法。用硅胶低压柱色谱、制备TLC及制备HPLC分离纯化了两个代谢产物并进行了光谱鉴定。结果表明,两个代谢物分别确定为6-和5-位羟基取代的黄皮酰胺。     

手性黄皮酰胺的研究进展

黄皮酰胺是从中药黄皮叶中提取到的天然成分,现已完成其16个光学活性异构体的合成和拆分。通过对其中一对对映体(-)黄皮酰胺和( )黄皮酰胺的深入研究发现,其代谢转化、药理作用等均具有立体选择性,即其中(-)黄皮酰胺是有效对映体,具有显著的保肝、促智、抗神经细胞凋亡等作用,而( )黄皮酰胺为劣映体。现对手性黄皮酰胺的代谢转化、药动学和对神经系统的作用及机制研究进展进行综述。     

黄皮酰胺对映体在大鼠肝微粒体中的酶促反应动力学黄皮酰胺对映体在大鼠肝微粒体中的酶促反应动力学

目的研究黄皮酰胺（clausenamide,Clau）对映体在大鼠肝微粒体中的酶促反应动力学并比较其立体选择性差异。方法应用反相HPLC法测定Clau对映体在体外代谢系统中的产物，并用Eadie-Hofstee作图法分析数据、求算酶促反应动力学参数K_m和V_max以及肝代谢速率V_max/K_m。结果在体外代谢系统中，左旋黄皮酰胺主要生成7-羟-Clau、5-羟-Clau和4-羟-Clau，其优势代谢途径为7位羟化；7位羟化代谢的V_max/K_m值高于5位和4位。右旋黄皮酰胺的4位羟化反应K_m最小、V_max最大, 因此代谢速率最高，是左旋体4位羟化的8倍；而其7-羟-Clau和5-羟-Clau 的产生量很小。结论黄皮酰胺对映体在大鼠肝微粒体中的羟化代谢存在明显的底物立体选择性差异。     

大鼠肝微粒体温孵体系中（＋）,（—）—黄皮酰胺及其代谢产物的LC—MS分析

目的：建立黄皮酰胺及其代谢产物的ＨＰＬＣ－ＥＳＩ－ＭＳ在线检测分析方法,并对未分离得到的微量代谢产物进行分析确证,探索ＬＣ－ＭＳ在代谢转化研究中的应用。方法：利用柱后补偿技术,采用正离子检测对大鼠肝微体中（＋）,（－）－黄皮酰胺及其代谢产物进行ＨＰＬＣ－ＥＳＩ－ＭＳ分析,根据ＭＳ的碎片信息检测主要的代谢产物,特别是对未分离得到的代谢产物的结构碎片进行分析,确定其结构。结果：除检测出主要已知代谢产物     

用固相萃取-核磁共振氢谱法研究大鼠尿液中R-(-)-布洛芬光活代谢产物

目的　用固相萃取-核磁共振氢谱法研究大鼠尿液中R-(-)-布洛芬代谢产物及异构体的转化。方法　将服用R-(-)-布洛芬后0～24 h大鼠尿液经固相萃取柱处理、核磁共振氢谱测定代谢产物的结构。结果　尿液中含有4个主要代谢产物：2＇-羟基-布洛芬及其葡糖苷酸结合物、1＇-羧基-布洛芬葡糖苷酸和布洛芬葡糖苷酸。后两者为非对映异构体混合物。结论　R-(-)-布洛芬在大鼠体内发生了异构体转化,异丁基侧链中末端甲基的氧化代谢具有立体选择性。     

手性黄皮酰胺生物转化的立体选择性

以相同的肝微粒体温孵体系对(+) 和(-) 黄皮酰胺(Cla)进行了温孵,以HPLC分析比较了代谢结果,发现(+)-和(-)-Cla所产生的主要代谢产物基本相同,但主要代谢产物在(+)-和(-)-Cla温孵体系中含量差别较大,左旋体代谢产生的CM1和CM5的量比右旋体大;CM2是左旋Cla的主要代谢产物之一,右旋体产生极小的量;而CM3是右旋Cla的主要代谢产物,左旋体产生的量较少. CM4, CM6是由CM3进一步代谢所产生的双羟基代谢产物,右旋体产生的量多于左旋体. 定量分析(+)-,(-)-Cla在肝微粒体中不同时间的代谢情况,发现(+)-,(-)-Cla在实验浓度下均为非线性动力学,二者代谢速率基本相同,不同时间代谢的立体选择性基本相同.     

LC-MS/MS法研究1-[1-(6-甲氧基-2-萘基)乙基]-2-(4-硝基苄基)-6,7-二甲氧基-1,2,3,4-四氢异喹啉氢溴酸盐在大鼠体内的代谢产物

采用液相色谱-串联质谱法对大鼠灌胃1-［1-(6-甲氧基-2-萘基)乙基］-2-(4-硝基苄基)-6,7-二甲氧基-1,2,3,4-四氢异喹啉氢溴酸盐(编号P91024)后粪便、尿液、胆汁和血浆中的主要代谢产物进行研究。通过比较给药样品和空白样品的全扫描总离子流色谱和选择离子扫描色谱图差别寻找I相代谢产物；根据其一级和二级质谱图，确定I相代谢产物的分子结构。完全提取I相代谢产物后的样品溶液，再用葡糖醛酸酶酶解，得II相结合物的苷元部分，采用与I相代谢产物鉴定同样方法寻找和鉴定II相代谢产物苷元的结构，进而确证II相代谢产物的分子结构。从大鼠粪便中鉴定出P91024的2个I相代谢物，从胆汁中鉴定出1个I相和5个II相代谢产物，从尿液中鉴定出1个I相和3个II相代谢产物，从血浆中鉴定出4个I相和1个II相代谢产物；并分别分析推测出它们的结构。P91024在大鼠体内被代谢转化为多种产物，利用LC-MS/MS可以快速寻找和鉴定。     

液相色谱-串联质谱法分析抗肿瘤新药乙烷硒啉在大鼠体内的代谢产物

本研究对抗肿瘤新药1,2-[二(1,2-苯并异硒唑-3(2H)-酮)]乙烷(乙烷硒啉,BBSKE)在大鼠体内的代谢产物进行鉴定。在灌胃给予大鼠单剂量乙烷硒啉200mg·kg-1后,采用液相色谱-串联质谱法(LC-MSn)对大鼠尿液、粪样、胆汁和血浆中的代谢产物进行检测,通过全扫描和选择离子扫描,以及根据多级质谱裂解规律对代谢物的结构进行分析。研究发现在大鼠尿样、粪样、胆汁和血浆中检测到3种Ⅰ相代谢产物和1种Ⅱ相代谢产物,其代谢途径分别为氧化、甲基化、硫甲基化和葡萄糖醛酸化反应,提示乙烷硒啉在大鼠体内的代谢方式可能是通过氧化、甲基化及葡萄糖醛酸化反应形成代谢产物。     

synapsinⅠ参与(-)黄皮酰胺增强齿状回突触传递功能

目的观察synapsinⅠ在(-)黄皮酰胺促进大鼠海马齿状回突触传递功能中的作用。方法用电生理方法观察(-)黄皮酰胺对基础突触传递功能的影响;采用Westernblot方法及共聚焦显微镜检测了(-)黄皮酰胺对synapsinⅠ磷酸化的时间、浓度依赖关系,以及确定促进synapsinⅠ激活的上游蛋白激酶。结果在整体动物中,(-)黄皮酰胺可明显增加海马齿状回群峰电位,并且脑室给药5 min即可促进海马synapsinⅠ磷酸化增强,15 min时皮层synapsinⅠ磷酸化增强最明显。0.1、1、10μmol.L-1(-)黄皮酰胺可浓度依赖性促进PC12细胞中synapsinⅠ激活,且10μmol.L-1(-)黄皮酰胺在1~2 min均可激活突触体和PC12细胞中synapsinⅠ。PKA抑制剂H89可抑制(-)黄皮酰胺对synapsinⅠ的磷酸化。结论(-)黄皮酰胺通过PKA促进synapsinⅠ磷酸化而增强基础突触传递活动。     

Investigations on the metabolic pathways of cyclosporine: I. Excretion of cyclosporine and its metabolites in human bile--isolation of 12 new cyclosporine metabolites.

1. Cyclosporine metabolites of known and unknown structures were isolated, by semi-preparative h.p.l.c., from human bile from the T-tube of liver-grafted patients, who received cyclosporine treatment. Their structures were elucidated by FAB mass spectrometry and 1H-n.m.r. spectroscopy. 2. Twelve of the cyclosporine metabolites, with known chemical structures, were isolated and identified using authentic standard material. 3. Four isolated fractions contained tri-hydroxylated metabolites; two fractions contained di-hydroxylated, demethylated metabolites; one fraction contained a tri-hydroxylated, demethylated metabolite; and one fraction a mono-hydroxylated, demethylated metabolite. The exact metabolism sites were partially defined. 4. Two carboxylated cyclosporine metabolites, of which one was hydroxylated in an unknown position, were isolated. 5. One new metabolite proved to be a glucuronylated phase II metabolite. Deglucuronylation of this metabolite by beta-glururonidase yielded metabolite AM1c. The proposed structure was AM1c-Glc; is a proposed extension of the Hawk's Cay nomenclature of the cyclosporine metabolites for glucuronylated metabolites. 6. One of the unknown metabolites was hydroxylated in two positions of amino acid 1. The proposed nomenclature was 'AM11d', where '1d' indicates hydroxylation at the delta C of amino acid 1. 7. A metabolite with an aldehyde functional group at amino acid 1, which had two isomeric forms, was isolated. I.r.-spectroscopy indicated that isomerism may be caused by conjugation of the aldehyde group with the double bond between C6 and C7 of amino acid 1.     

In vitro and in vivo studies on the stereoselective pharmacokinetics and biotransformation of an (S)-(–)- and (R)-(+)-pyrazolotriazine sulfoxide in the male rat

1. BOF-4272 (a pyrazolotriazine sulfoxide) is a new drug for the treatment of hyperuricemia. The pharmacokinetics and biotransformation of both BOF-4272 enantiomers were investigated in rat. 2. Plasma concentrations after intravenous or oral administration of racemic BOF-4272 to rat were significantly higher for (S) - than for (R) -BOF-4272. 3. The concentration of (S) -BOF-4272 in hepatocyte culture medium 24 h after the addition of racemic BOF-4272 was higher than that of (R) -BOF-4272. 4. Liver concentrations after oral adminstration of racemic BOF-4272 to rat were significantly higher for (R) - than for (S) -BOF-4272. Kidney concentrations were significantly higher for (S) - than for (R) -BOF-4272. 5. Hepatic biotransformation from BOF-4272 to unknown metabolites, possibly conjugates, is stereoselective. Biotransformation of both enantiomers to the sulfone metabolite by cytochrome P450 in rat liver may also be stereoselective. 6. Biotransformation of the sulfide metabolite of BOF-4272 to BOF-4272 may be stereoselective, possibly due to the stereospecificity of flavin-containing mono-oxidase and/or cyrochrome P450. 7. The stereoselectivity of plasma concentrations of racemic BOF-4272 after intravenous or oral administration appears to be due to differences in the hepatic uptake of the two enantiomers as well as the stereoselective biotransformation of the sulfide metabolite to BOF-4272 in rat liver. Biotransformation of BOF-4272 in rat liver may also be stereoselective.     

In vitro and in vivo studies on the stereoselective pharmacokinetics and biotransformation of an (S)-(-)- and (R)-(+)-pyrazolotriazine sulfoxide in the male rat

1. BOF-4272 (a pyrazolotriazine sulfoxide) is a new drug for the treatment of hyperuricemia. The pharmacokinetics and biotransformation of both BOF-4272 enantiomers were investigated in rat. 2. Plasma concentrations after intravenous or oral administration of racemic BOF-4272 to rat were significantly higher for (S)- than for (R)-BOF-4272. 3. The concentration of (S)-BOF-4272 in hepatocyte culture medium 24 h after the addition of racemic BOF-4272 was higher than that of (R)-BOF-4272. 4. Liver concentrations after oral adminstration of racemic BOF-4272 to rat were significantly higher for (R)- than for (S)-BOF-4272. Kidney concentrations were significantly higher for (S)- than for (R)-BOF-4272. 5. Hepatic biotransformation from BOF-4272 to unknown metabolites, possibly conjugates, is stereoselective. Biotransformation of both enantiomers to the sulfone metabolite by cytochrome P450 in rat liver may also be stereoselective. 6. Biotransformation of the sulfide metabolite of BOF-4272 to BOF-4272 may be stereoselective, possibly due to the stereospecificity of flavin-containing mono-oxidase and/or cyrochrome P450. 7. The stereoselectivity of plasma concentrations of racemic BOF-4272 after intravenous or oral administration appears to be due to differences in the hepatic uptake of the two enantiomers as well as the stereoselective biotransformation of the sulfide metabolite to BOF-4272 in rat liver. Biotransformation of BOF-4272 in rat liver may also be stereoselective.     

Investigations on the metabolic pathways of cyclosporine: I. Excretion of cyclosporine and its metabolites in human bile—isolation of 12 new cyclosporine metabolites

1. Cyclosporine metabolites of known and unknown structures were isolated, by semi-preparative?h.p.l.c., from human bile from the T-tube of liver-grafted patients, who received cyclosporine treatment. Their structures were elucidated by FAB mass spectrometry and ¹H-n.m.r. spectroscopy.

2. Twelve of the cyclosporine metabolites, with known chemical structures, were isolated and identified using authentic standard material.

3. Four isolated fractions contained tri-hydroxylated metabolites; two fractions contained di-hydroxylated, demethylated metabolites; one fraction contained a trihydroxylated, demethylated metabolite; and one fraction a mono-hydroxylated, demethylated metabolite. The exact metabolism sites were partially defined.

4. Two carboxylated cyclosporine metabolites, of which one was hydroxylated in an unknown position, were isolated.

5. One new metabolite proved to be a glucuronylated phase II metabolite. Deglucuronylation of this metabolite by β-glururonidase yielded metabolite AM1c. The proposed structure was AM1c-Gic; is a proposed extension of the Hawk's Cay nomenclature of the cyclosporine metabolites for glucuronylated metabolites.

6. One of the unknown metabolites was hydroxylated in two positions of amino acid 1. The proposed nomenclature was ‘AM11d’, where ‘1d’ indicates hydroxylation at the δC of amino acid 1.

7. A metabolite with an aldehyde functional group at amino acid 1, which had two isomeric forms, was isolated. I.r.-spectroscopy indicated that isomerism may be caused by conjugation of the aldehyde group with the double bond between C6 and C7 of amino acid 1.     

Characterization of the in vitro metabolic profile of amlodipine in rat using liquid chromatography-mass spectrometry.

In the present study, the metabolic profile of amlodipine, a well-known calcium channel blocker, was investigated employing liquid chromatography-mass spectrometric (LC/MS) techniques. Two different types of mass spectrometers - a triple-quadrupole (QqQ) and a quadrupole time-of-flight (Q-TOF) mass spectrometer - were utilized to acquire structural information on amlodipine metabolites. The metabolites were produced by incubation of amlodipine with primary cultures of rat hepatocytes. Incubations from rat hepatocytes were analyzed with LC-MS/MS, and 21 phase I and phase II metabolites were detected. Their product ion spectra were acquired and interpreted, and structures were proposed. Accurate mass measurement using LC-Q-TOF was used to determine the elemental composition of metabolites and thus to confirm the proposed structures of these metabolites. Mainly phase I metabolic changes were observed including dehydrogenation of the dihydropyridine core, as well as reactions of side chains, such as hydrolysis of ester bonds, hydroxylation, N-acetylation, oxidative deamination, and their combinations. The only phase II metabolite detected was the glucuronide of a dehydrogenated, deaminated metabolite of amlodipine. We propose several in vitro metabolic pathways of amlodipine in rat, based on our analysis of the metabolites detected and characterized.