title: Transport of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Ala-His-Leu-Leu Across Human Intestinal Epithelial Caco-2 Cells.
abstract: The transport behavior and absorption mechanism of Ala-His-Leu-Leu (AHLL) intestinal absorption in Caco-2 cell monolayers were clarified systemically. The safe absorptive concentration of AHLL was 200 μg/mL, which was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. The permeation of AHLL was concentration dependent in a bidirectional transfer and reached a plateau at 90 min. The efflux ratio was above 0.5, suggesting that AHLL was absorbed by both active transport and passive diffusion. The apparent permeability coefficients (Papp) of AHLL both from the apical (AP) to basolateral (BL) side (PappAB) and from the BL to AP side (PappBA) decreased when the temperature was lowered from 37°C to 4°C.The uptake of AHLL was more at pH 7.4 than at other pHs. Both verapamil and (E)-3-[[[3-[2-(7-chloro-2- quinolinyl) ethenyl] phenyl]-[[(3-dimethyl amino)-3-oxopropyl]thio] methyl] thio]-propanoic acid (MK571) inhibited the absorption of AHLL, indicating that P-glycoprotein and multi-drug resistant proteins (MRPs) were all involved in AHLL secretion, especially multi-drug resistant protein 2 (MRP2). AHLL was transported through both trans- and paracellular pathways across the Caco-2 cell monolayer. This work first elucidates the AHLL absorption mechanism in Caco-2 cells and provides the basis for future studies on the improvement of bioavailability.
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Xiudong
authors.initials: X
authors.lastname: Xia
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Agricultural Products Processing , Jiangsu Academy of Agricultural Science, Nanjing, China .
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Zhou
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism*; D001692:Biological Transport; D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000806:Angiotensin-Converting Enzyme Inhibitors; D010455:Peptides; D007703:Peptidyl-Dipeptidase A
keywords: Ala-His-Leu-Leu; Caco-2 cell monolayer; antihypertensive peptide; intestinal absorption mechanism; transport