Resumen
Previous in vitro studies the have suggested anti-inflammatory properties of caffeine. Coffee is also rich in phenolic acids with several potential health benefits (chlorogenic acids), mainly 5-caffeoylquinic acid (5-CQA). The aim of the present study was to determine the effect of caffeine and 5-CQA, using concentrations comparable to typical human consumption, on LPS-induced cytokine production in whole blood in vitro cultures. Whole blood samples (n = 10) were stimulated for 24 h with LPS in the presence of caffeine or 5-CQA. The concentrations of various cytokines, malondialdehyde (MDA) and adenosine-3',5'-cyclic monophosphate (cAMP) were determined in the culture media. Significant effects of caffeine were found only for the stimulated production of TNF-a (p = 0.014) and cAMP (p = 0.001). However, only the highest caffeine concentration (50 µM) induced lower TNF-a (p = 0.016) and higher cAMP (p = 0.006) levels in comparison to the control. The 5-CQA only influenced the stimulated production of IL-6 (p = 0.002), with lower values for the highest 5-CQA concentrations (2 µM: p = 0.012; 20 µM: p < 0.001). Neither caffeine (p = 0.227) nor 5-CQA (p = 0.259) influenced MDA concentrations. In conclusion, both caffeine and 5-CQA exerted limited in vitro anti-inflammatory effects. For caffeine, these effects were attained with high physiological concentrations. However, for 5-CQA, supraphysiological concentrations were needed.