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09:11
Caffeine Extraction, Enzymatic Activity and Gene Expression of Caffeine Synthase from Plant Cell Suspensions
Published on: October 2, 2018
Structure- and dose-absorption relationships of coffee polyphenols
Thomas Erk1, Johanna Hauser, Gary Williamson
1Division of Chemistry, Department of Food Chemistry and Toxicology, Molecular Nutrition, University of Kaiserslautern, Kaiserslautern, Germany.
Biofactors (Oxford, England)
|April 5, 2013
Summary
Coffee
Area of Science:
- Food science and nutrition
- Pharmacokinetics and drug delivery
- Gastrointestinal physiology
Background:
- Chlorogenic acids (CGAs) are abundant polyphenols in coffee with potential health benefits.
- Understanding CGA bioavailability in the upper gastrointestinal tract is crucial as absorption here prevents colonic metabolism.
- No prior studies have detailed structure-absorption relationships for CGAs.
Purpose of the Study:
- To investigate the ex vivo absorption of major coffee chlorogenic acids (CGAs) in the pig jejunum.
- To elucidate the structure-absorption relationships and transport mechanisms of CGAs.
- To identify the role of efflux transporters in CGA bioavailability.
Main Methods:
- Ex vivo absorption experiments using pig jejunal mucosa in an Ussing chamber model.
- Incubation of individual CGAs (caffeoylquinic acid, feruloylquinic acid, caffeic acid, dicaffeoylquinic acid, D-(-)-quinic acid) at physiological concentrations.
- Quantification by HPLC-diode array detection and HPLC-MS/MS; identification of ABC-efflux transporters via Western blot.
Main Results:
- Absorption percentages in pig jejunum: D-(-)-quinic acid (≈ 4%) > feruloylquinic acid (≈ 2%) > caffeic acid (≈ 1.5%) > caffeoylquinic acid (≈ 1%) > dicaffeoylquinic acid (trace).
- Absorption mechanism for 5-caffeoylquinic acid appeared to be passive diffusion, but secretion was affected by NaN3, indicating active efflux.
- MDR1 and MRP2 ABC-efflux transporters were identified in the pig jejunal mucosa.
Conclusions:
- Active efflux significantly influences chlorogenic acid bioavailability in the jejunum.
- The physicochemical properties of CGAs govern their absorption mechanisms in the upper gastrointestinal tract.
- Identification of MDR1 and MRP2 transporters provides new insights into CGA transport.
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