A lightly roasted coffee extract improves blood and tissue redox status in rats through enhancement of GSH biosynthesis.

Coffee is a highly consumed beverage with many putative beneficial health effects, however these often come from observational studies. In the current work, a lightly roasted coffee extract that has previously been reported to exhibit potent antioxidant properties was administered for two weeks in rats to examine the potential improvement of blood and tissue redox status. The dose was equivalent to a moderate human daily consumption. According to our results, coffee exerted beneficial effects in all tissues mainly by increasing reduced glutathione (GSH) levels. Interestingly, the brain was the most significantly affected tissue, while the gastrointestinal tract, the main metabolic organs and the quadriceps were also benefited. In addition, protein and lipid oxidation was reduced in several tissues. The observed increase in GSH was attributed to increased levels of the rate-limiting enzyme in its biosynthesis pathway, namely γ-glutamylcysteine ligase both in the protein and gene levels. Overall, moderate coffee consumption showed beneficial short term effects in rat tissues by stimulating parts of the endogenous antioxidant mechanisms.