title: Investigation of intestinal absorption and disposition of green tea catechins by Caco-2 monolayer model.
abstract: The current study was designed to investigate the absorption mechanism and identify the possible disposition pathways of green tea catechins (GTC), including epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), during their absorption across small intestine by Caco-2 monolayer model. The transport of each GTC from both apical to basolateral and basolateral to apical directions was measured in the absence and the presence of MK571, an MRP inhibitor. HPLC and LC/MS were employed to identify the possible metabolites of the four GTC formed during their bidirectional transport processes. The results indicated that the four GTC showed limited transepithelial absorption with relatively small P(app) values. However, significant efflux mediated by MRP was observed during the secretion of GTC, especially the non-gallated catechins. Methylation and sulfation were the main biotransformation pathways of GTC during their secretion transport and the efflux of the related metabolites seem to be mediated by MRP.
authors.affiliation: School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Moses S S
authors.initials: MS
authors.lastname: Chow
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zuo
mesh_terms: D001692:Biological Transport; D018938:Caco-2 Cells; D002392:Catechin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007408:Intestinal Absorption; D013058:Mass Spectrometry; D013662:Tea
chemical_list: D013662:Tea; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; C057580:gallocatechol