May 29, 2019

Alkylpyrazines from coffee are extensively metabolized to pyrazine carboxylic acids in the human body

J I Kremer et al, 2019. Alkylpyrazines from coffee are extensively metabolized to pyrazine carboxylic acids in the human body, Mol Nutr Food Res, published online.


Scope: Coffee is a complex mixture of over 1000 compounds, including diverse heteroaromatic compounds such as alkylpyrazines. Little is known about the intake, metabolism, and bodily distribution of these compounds. We therefore conducted a human intervention study to investigate the excretion of alkylpyrazine metabolites in urine after the ingestion of brewed coffee containing alkylpyrazines. Methods and results: After consuming a diet without heat-processed food, ten volunteers consumed 500 mL of freshly brewed coffee prepared from coffee pads, providing intakes of 2-methylpyrazine (2-MeP), 2,5-dimethylpyrazine (2,5-DMeP), and 2,6-dimethylpyrazine (2,6-DMeP) amounting to 17.2 µmol, 4.4 µmol, and 4.9 µmol, respectively. These alkylpyrazines were metabolized into the corresponding pyrazine carboxylic acids, namely pyrazine-2-carboxylic acid (PA), 5-hydroxypyrazine-2-carboxylic acid (5-OHPA), 5-methylpyrazine-2-carboxylic acid (5-MePA), and 6-methylpyrazine-2-carboxylic acid (6-MePA). In total, 64% of the ingested 2-MeP was excreted as PA, as well as 26% as 5-OHPA, while 91% and 97% of the ingested 2,5-DMeP and 2,6-DMeP were recovered as 5-MePA and 6-MePA, respectively in urine samples collected after coffee consumption. Conclusion: This study provides evidence that alkylpyrazines are rapidly metabolized into the corresponding carboxylic acids and excreted via urine by humans, which is consistent with earlier rodent studies.

Modtag nyhedsbrev

Ja tak, jeg vil gerne modtage nyhedsbrev, når der er noget nyt om kaffe og helbred.