Publication in refereed journal
香港中文大学研究人员 ( 现职)
| 左中教授 (药剂学院) |
全文
| 数位物件识别号 (DOI) http://dx.doi.org/10.1211/jpp.59.3.0009 |
引用次数
Web of Sciencehttp://aims.cuhk.edu.hk/converis/portal/Publication/18WOS source URL
其它资讯
摘要The bioavailability of green tea catechins (GTCs), including epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC) is low in both animals and humans. The contribution of intestinal efflux to this low bioavailability has been suggested by previous studies. The objective of the present study was to investigate the kinetics of efflux transport of the four major GTCs in Caco-2 cell lines, to provide comparison on the efflux transport between each GTC. The basal-to-apical transport of each GTC at concentrations ranging from 15 to 265 mu M was examined using the Caco-2 cell monolayer model. Transported amount of GTC was measured by high-performance liquid chromatography with electrochemical detection. Kinetic parameters, V-max, Km and V-max/K-m were determined and compared among the four studied GTCs. The extent of basal-toapical transport was, in descending order, EC > EGC > ECG approximate to EGCG. Kinetic studies indicated that active and saturable efflux transport of EC took place in Caco-2 cells, with a Km of 131 Mann, a Vmax of 0.0249 nmol min cm(-2) and an intrinsic clearance (V-max/K-m) of 0.19 /mu L min cm(-2). No saturation could be observed for the efflux transport of EGC, ECG and EGCG even at concentrations up to about 200 lion, which may be due to their low affinity towards the transporters at the concentration range studied. In conclusion, the extent of efflux transport of GTCs in Caco-2 cells was, in descending order, EC > EGC > ECG approximate to EGCG, which may reflect the order of elimination occurring in the intestine. The kinetic studies showed the importance of efflux transporters in basal-to-apical transport of EC and suggests their role in the limited oral bioavailability of EC.
着者Chan KY, Zhang L, Zuo Z
期刊名称Journal of Pharmacy and Pharmacology
详细描述To ORKTS: Financial support from RGC competitive earmarked grant (CUHK 4122/01M) is acknowledged.
出版年份2007
月份3
日期1
卷号59
期次3
出版社PHARMACEUTICAL PRESS-ROYAL PHARMACEUTICAL SOC GREAT BRITIAN
页次395 - 400
国际标準期刊号0022-3573
电子国际标準期刊号2042-7158
语言英式英语
Web of Science 学科类别Pharmacology & Pharmacy; PHARMACOLOGY & PHARMACY
