title: Inhibitory effect of a bitter melon extract on the P-glycoprotein activity in intestinal Caco-2 cells.
abstract: Extracts of bitter melon, soybean, dokudami and welsh onion by 40% methanol increased the accumulation of rhodamine-123 by Caco-2 cells, suggesting that these extracts inhibited P-glycoprotein (P-gp). The extract of bitter melon was separated in a tC18 cartridge column and the eluate from 80% acetonitrile most markedly increased the [(3)H]-daunomycin accumulation by Caco-2 cells. The inhibitory compounds in the bitter melon fraction were isolated by HPLC with Pegasil C4 and Pegasil ODS columns. The HPLC fraction having the highest activity was analyzed by (1)H-NMR and FAB-MS, and the active compound was identified as 1-monopalmitin. The inhibitory activities of 1-monopalmitin and its related compounds suggested that the inhibition of P-gp activity was not dependent on the degree of unsaturation of fatty acid in the monoglyceride, but on the chain length. It was also suggested that the monoglyceride structure played an important role in the inhibition of P-gp activity. Monoglycerides could therefore alter the pharmacokinetics of drugs by inhibiting the P-gp-mediated efflux.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Konishi
authors.forename: Hideo
authors.initials: H
authors.lastname: Satsu
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hatsugai
authors.forename: Koichi
authors.initials: K
authors.lastname: Aizawa
authors.forename: Takahiro
authors.initials: T
authors.lastname: Inakuma
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagata
authors.forename: Sho-Hei
authors.initials: SH
authors.lastname: Sakuda
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Nagasawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Shimizu
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D000596:Amino Acids / Q000493:pharmacokinetics; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D003630:Daunorubicin / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D005638:Fruit; D005989:Glycerides / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D000432:Methanol / Q000737:chemistry; D029777:Momordica charantia; D010936:Plant Extracts / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D011402:Pronase / Q000378:metabolism; D020112:Rhodamine 123 / Q000493:pharmacokinetics; D014675:Vegetables
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D000596:Amino Acids; D005989:Glycerides; D010936:Plant Extracts; D020112:Rhodamine 123; D007770:L-Lactate Dehydrogenase; D011402:Pronase; C027735:palmitoyl glycerol; D000432:Methanol; D003630:Daunorubicin