title: Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues.
abstract: Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (-)-Epicatechin-gallate (ECG) and (-)-epigallocatechin-gallate (EGCG) inhibited D-glucose transport by GLUT1 and PfHT, and D-fructose transport by GLUT5, with apparent K(i) values between 45 and 117 microM. BboHT1 was more potently inhibited by the ungallated catechins (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), with apparent K(i) values of 108 and 168 microM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external D-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents.
authors: Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London, UK.
authors: Ksenija
authors: K
authors: Slavic
authors: Elvira T
authors: ET
authors: Derbyshire
authors: Richard J
authors: RJ
authors: Naftalin
authors: Sanjeev
authors: S
authors: Krishna
authors: Henry M
authors: HM
authors: Staines
mesh_terms: D000818:Animals; D016793:Babesia bovis / Q000201:enzymology*; D002392:Catechin / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D051272:Glucose Transporter Type 1 / Q000037:antagonists & inhibitors*; D051296:Glucose Transporter Type 5 / Q000037:antagonists & inhibitors*; D008322:Mammals; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors*; D009865:Oocytes; D010963:Plasmodium falciparum / Q000201:enzymology*; D013662:Tea / Q000737:chemistry*; D014982:Xenopus laevis
chemical_list: D004791:Enzyme Inhibitors; D051272:Glucose Transporter Type 1; D051296:Glucose Transporter Type 5; D009004:Monosaccharide Transport Proteins; D013662:Tea; D002392:Catechin