Measurement of the Intracellular pH in Human Stomach Cells: A Novel Approach To Evaluate the Gastric Acid Secretory Potential of Coffee Beverages

Abstract

As the consumption of coffee beverages sometimes is reported to cause gastric irritation, for which an increased stomach acid secretion is one of the promoting factors, different processing technologies such as steam-treatment have been developed to reduce putative stomach irritating compounds. There is evidence-based data neither on the effect of detailed processing variations nor on individual coffee components affecting the proton secretory activity (PSA). This work aimed at developing a screening model suitable for investigating the effects of commercial coffee beverages and components thereof on human parietal cells. Human gastric cancer cells (HGT-1) were treated with reconstituted freeze-dried coffee beverages prepared from customary coffee products such as regular coffee (RC, n = 4), mild bean coffee (MBC, n = 5), stomach friendly coffee (SFC, n = 4), and SFC decaffeinated (SFCD, n = 3). PSA was analyzed by flow cytometry using the pH-sensitive dye SNARF-AM. Treatment of the cells with MBC did not result in a PSA different from RC treatment (p <or= 0.07), whereas cells treated with SFC (p <or= 0.04) or SFCD (p <or= 0.03) showed a significantly lower PSA than those treated with RC. Quantitative and principle component analysis of putative stomach irritating compounds revealed significantly reduced contents of (beta)N-alkanoyl-5-hydroxytryptamides, caffeine, N-methylpyridinium, and catechol in SFCD compared to RC. However, none of these compounds seem to act as the sole key bioactive reducing the PSA of SFCD, since their contents in MBC and SFC samples were not different from those in RC samples, although the PSA of these beverages was significantly lower than that of reconstituted freeze-dried RC beverage.

Antioxidant‐rich coffee reduces DNA damage, elevates glutathione status and contributes to weight control: Results from an intervention study

“…Study coffee characteristics Concentrations of thermally labile green coffee bean constituents, such as CQAs (580 mg/L) in the study coffee brew were slightly lower than those reported in the literature for commercial filter coffee [7]. The concentrations of NMP (72 mg/L) were in the upper range of dark roasts [5].…”

“…The coffee was freshly brewed in a conventional coffee filter machine immediately before each individual 250-mL consumption. The coffee brew was analytically characterized using HPLC-DAD and HPLC-MS/MS [7] (Supporting Information, preparation and analysis of the coffee brew studied).…”

Quantitation of βN-Alkanoyl-5-hydroxytryptamides in Coffee by Means of LC-MS/MS-SIDA and Assessment of Their Gastric Acid Secretion Potential Using the HGT-1 Cell Assay

“…The cells were set to a concentration of 1 Â 10 6 viable cells per milliliter of PBS. The gastric acid secretory acitvity of the cells was measured by the determination of the intracellular proton index (IPX) using the fluorescence dye carboxy-SNARF-AM as a probe for the measurement of the intracellular pH value (29). HGT-1 cells were loaded with the dye (3 μmol/L) for 30 min on ice.…”

“…The objective of the present investigation was, therefore, to develop a sensitive HPLC-MS/MS method enabling the accurate and reliable quantitative analysis of β N-alkanoyl-5-hydroxytryptamides in coffee beverages by means of a stable isotope dilution analysis, and to evaluate the activity of these compounds on gastric acid (GA) secretion by using an in vitro HGT-1 cell assay, which has recently been developed and successfully applied to assess the GA secretion induced by coffee beverages (29).…”

Cardiometabolic effects of two coffee blends differing in content for major constituents in overweight adults: a randomized controlled trial

“…The coffee samples were analytically characterized using highperformance liquid chromatography diode array detector (HPLC-DAD) and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods previously described. Caffeine and CQA were quantified by HPLC-DAD (324, 272 nm) with external calibration [23]. NMP and trigonelline in coffee were quantified by stable isotope dilution analysis with synthetic d 3 -NMP after sample cleanup via solid-phase extraction (SPE) on RP18 [24].…”