Comparative Action of Blue Food Colorants (Genipin, Patent Blue V, and Brilliant Blue FCF); Their Effect on Oxidative Stress in Human Plasma and Blood Platelets In Vitro

The influence of natural and synthetic blue food colorants on the human body, including the cardiovascular system, is a complex and not fully understood topic. Considering that various papers have demonstrated that oxidative stress is a crucial step in the development of cardiovascular diseases (CVDs), our experiments on the pro- or antioxidant action of three blue food colorants (one natural colorant—genipin—and two synthetic colorants—brilliant blue FCF and patent blue V) focused on two aspects that are important for the development of CVDs: the level of biomarkers of oxidative stress induced by H2O2/Fe2+ (the donor of hydroxyl radicals—one of the most aggressive reactive oxygen species produced in humans) in human blood platelets and human plasma, as well as the arachidonic acid cascade in blood platelets stimulated by thrombin (in vitro). Our results demonstrated that two tested blue colorants—genipin and brilliant blue FCF (at four used concentrations: 2, 10, 20, and 200 µM)—reduced plasma lipid peroxidation induced by H2O2/Fe2+. Moreover, all tested blue colorants (genipin, brilliant blue FCF, and patent blue V; at the concentrations 2, 10, 20, and 200 µM) inhibited lipid peroxidation in blood platelets treated with H2O2/Fe2+. In contrast, only genipin (at the highest used concentration—200 µM) statistically significantly reduced plasma protein carbonylation induced by H2O2/Fe2+ (inhibition of this process: about 25%). However, all tested food colorants decreased blood platelet protein carbonylation stimulated by H2O2/Fe2+, but their action was not always statistically significant. In addition, we noted that all used blue food colorants (1–200 µM) have protector effects on the change in the level of thiol groups in plasma proteins stimulated by H2O2/Fe2+, but these tested colorants change the level of thiol groups in blood platelets treated with H2O2/Fe2+ only at the highest used concentration—200 µM. In conclusion, the present study provides the first data on the antioxidant potential of genipin, brilliant blue FCF, and patent blue V in selected elements of blood treated with H2O2/Fe2+. Earlier and current studies have indicated the promising potential of these blue food colorants, especially genipin (without cytotoxicity toward human blood platelets), which can modify the oxidative stress of platelets and plasma in vitro at concentrations (1–200 µM) which can be obtained in blood during its administration. However, the presented results have limitations, especially concerning the mechanistic clarity surrounding the antioxidant properties of the tested blue food colorants. Therefore, further in vivo experiments are needed to provide a better understanding of their antioxidant potential.