October 7, 2011
T L Farrell et al, Absorption and metabolism of chlorogenic acids in cultured gastric epithelial monolayers, Drug Metabolism Disp, 2011, published online ahead of print.
Gastric absorption of feruloylquinic acid and di-O-caffeoylquinic acid analogs has never been investigated despite their potential contribution to the proposed beneficial health effects leading to reduced risk of type 2 diabetes. Using a cultured gastric epithelial model, with an acidic apical pH, the relative permeability coefficients (Papp) and metabolic fate of a series of chlorogenic acids (CGAs) were investigated. Mechanistic studies were performed in the apical to basal direction and demonstrated differential rates of absorption for different CGA subgroups. For the first time we show intact absorption of feruloylquinic acids and caffeoylquinic acid lactones across the gastric epithelium (Papp ~ 0.2 cm/s). Transport appeared to be mainly by passive diffusion, since good linearity was observed over the incubation period and test concentrations, and we speculated that a potential carrier mediated component may be involved in uptake of certain 4-acyl CGA isomers. In contrast, absorption of intact di-O-caffeoylquinic acids was rapid (Papp ~ 2 to 10 cm/s), but nonlinear with respect to time and concentration dependence, which was potentially limited by interaction with an efflux transporter and/or pH gradient dependence. For the first time methylation is shown in gastric mucosa. Furthermore, isoferulic acid, dimethoxycinnamic acid and ferulic acid were identified as novel gastric metabolites of CGA biotransformation. We propose that the stomach is the first location for the release of hydroxycinnamic acids, which could explain their early detection following coffee consumption.
Ja tak, jeg vil gerne modtage nyhedsbrev, når der er noget nyt om kaffe og helbred.