Mata-Bilbao Maria de Lourdes, Andrés-Lacueva Cristina, Roura Elena, Jáuregui Olga, Escribano Elvira, Torre Celina, Lamuela-Raventós Rosa M
Department of Nutrition and Food Science, XARTA, INSA, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
Br J Nutr. 2008 Sep;100(3):496-502. doi: 10.1017/S0007114507898692. Epub 2008 Jan 21.
The present study evaluates for the first time in dogs, the kinetics of green tea catechins and their metabolic forms in plasma and urine. Ten beagles were administered 173 mg (12.35 mg/kg body weight) of catechins as a green tea extract, in capsules. Blood samples were collected during 24 h after intake and urine samples were collected during the following periods of time: 0-2, 2-6, 6-8 and 8-24 h. Two catechins with a galloyl moiety and three conjugated metabolites were detected in plasma. Most of the detected forms in plasma reached their maximum plasma concentration (Cmax) at around 1 h. Median Cmax for ( - )-epigallocatechin-3-gallate (EGCG), ( - )-epicatechin-3-gallate (ECG), ( - )-epigallocatechin glucuronide (EGC-glucuronide), ( - )-epicatechin glucuronide (EC-glucuronide), ( - )-epicatechin sulphate (EC-sulphate) were 0.3 (range 0.1-1.9), 0.1 (range 0-0.4), 0.8 (range 0.2-3.9), 0.2 (range 0.1-1.7) and 1 (range 0.3-3.4) micromol/l, respectively. The areas under the plasma concentration v. time curves (AUC0 --> 24) were 427 (range 102-1185) micromol/l x min for EGC-glucuronide, 112 (range 53-919) micromol/l x min for EC-sulphate, 71 (range 26-306) micromol/l x min for EGCG, 40 (range 12-258) micromol/l x min for EC-glucuronide and 14 (range 0.1-124) micromol/l x min for ECG. The values of mean residence time (MRT0 --> 24) were 5 (range 2-16), 2 (range 1-11), 10 (range 2-13), 3 (range 2-16) and 2.4 (range 1-18) h for EGCG, ECG, EGC-glucuronide, EC-glucuronide and EC-sulphate, respectively. In urine, catechins were present as conjugated forms, suggesting bile excretion of EGCG and ECG. Green tea catechins are absorbed following an oral administration and EGC-glucuronide is the metabolic form that remains in the organism for a longer period of time, suggesting that this compound could suffer an enterohepatic cycle.
本研究首次在犬类中评估了绿茶儿茶素及其代谢产物在血浆和尿液中的动力学。给10只比格犬口服173毫克（12.35毫克/千克体重）的儿茶素（以绿茶提取物胶囊形式）。摄入后24小时内采集血样，在随后的时间段（0 - 2小时、2 - 6小时、6 - 8小时和8 - 24小时）采集尿样。在血浆中检测到两种带有没食子酰基部分的儿茶素和三种共轭代谢产物。血浆中检测到的大多数形式在约1小时时达到其最大血浆浓度（Cmax）。（ - ）-表没食子儿茶素-3-没食子酸酯（EGCG）、（ - ）-表儿茶素-3-没食子酸酯（ECG）、（ - ）-表没食子儿茶素葡萄糖醛酸苷（EGC-葡萄糖醛酸苷）、（ - ）-表儿茶素葡萄糖醛酸苷（EC-葡萄糖醛酸苷）、（ - ）-表儿茶素硫酸盐（EC-硫酸盐）的Cmax中位数分别为0.3（范围0.1 - 1.9）、0.1（范围0 - 0.4）、0.8（范围0.2 - 3.9）、0.2（范围0.1 - 1.7）和1（范围0.3 - 3.4）微摩尔/升。血浆浓度-时间曲线下面积（AUC0→24）对于EGC-葡萄糖醛酸苷为427（范围102 - 1185）微摩尔/升·分钟，对于EC-硫酸盐为112（范围53 - 919）微摩尔/升·分钟，对于EGCG为71（范围26 - 306）微摩尔/升·分钟，对于EC-葡萄糖醛酸苷为40（范围12 - 258）微摩尔/升·分钟，对于ECG为14（范围0.1 - 124）微摩尔/升·分钟。平均驻留时间（MRT0→24）的值对于EGCG、ECG、EGC-葡萄糖醛酸苷、EC-葡萄糖醛酸苷和EC-硫酸盐分别为5（范围2 - 16）、2（范围1 - 11）、10（范围2 - 13）、3（范围2 - 16）和2.4（范围1 - 18）小时。在尿液中，儿茶素以共轭形式存在，表明EGCG和ECG通过胆汁排泄。口服绿茶儿茶素后可被吸收，EGC-葡萄糖醛酸苷是在体内留存时间较长的代谢形式，表明该化合物可能经历肠肝循环。
