In vitro enzymic hydrolysis of chlorogenic acids in coffee.

Scope: Coffee is rich in quinic acid esters of phenolic acids (chlorogenic acids) but also contains some free phenolic acids. A proportion of phenolic acids appear in the blood rapidly after coffee consumption due to absorption in the small intestine. We investigated in vitro whether this appearance could potentially be derived from free phenolic acids in instant coffee or from hydrolysis of chlorogenic acids by pancreatic or brush border enzymes.

Changes in the frequencies of human hematopoietic stem and progenitor cells with age and site.

This study enumerated CD45(hi)/CD34(+) and CD45(hi)/CD133(+) human hematopoietic stem cells (HSCs) and progenitor granulocyte-macrophage colony forming cells (GM-CFCs) in blood and trochanteric and femoral bone marrow in 233 individuals. Stem cell frequencies were determined with multiparameter flow cytometry and using an internal control to determine the intrinsic variance of the assays. Progenitor cell frequency was determined using a standard colony assay technique.

Attenuation of glucose transport across Caco-2 cell monolayers by a polyphenol-rich herbal extract: interactions with SGLT1 and GLUT2 transporters.

Previous studies have indicated that secondary plant metabolites may modulate glucose absorption in the small intestine. We have characterized a polyphenol-rich herbal extract and its potential intestinal metabolites by LC-MS(2) and investigated the inhibition of glucose transporters SGLT1 and GLUT2 using the well-characterized Caco-2 intestinal model. Differentiated Caco-2 monolayers were incubated with an extract of a mixture of herbs and spices.

Absorption of dimethoxycinnamic acid derivatives in vitro and pharmacokinetic profile in human plasma following coffee consumption.

Scope: This study reports the 24 h human plasma pharmacokinetics of 3,4-dimethoxycinnamic acid (dimethoxycinnamic acid) after consumption of coffee, and the membrane transport characteristics of certain dimethoxycinnamic acid derivatives, as present in coffee.

Methods And Results: Eight healthy human volunteers consumed a low-polyphenol diet for 24 h before drinking 400 mL of commercially available coffee. Plasma samples were collected over 24 h and analyzed by HPLC-MS(2) .

Predicting phenolic acid absorption in Caco-2 cells: a theoretical permeability model and mechanistic study.

There is a considerable need to rationalize the membrane permeability and mechanism of transport for potential nutraceuticals. The aim of this investigation was to develop a theoretical permeability equation, based on a reported descriptive absorption model, enabling calculation of the transcellular component of absorption across Caco-2 monolayers. Published data for Caco-2 permeability of 30 drugs transported by the transcellular route were correlated with the descriptors 1-octanol/water distribution coefficient (log D, pH 7.

Absorption and metabolism of chlorogenic acids in cultured gastric epithelial monolayers.

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 (P(app)) 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.