The Effect of Safranal on Th1/Th2 Cytokine Balance

Background: Several biological and medical benefits of Saffron, Crocus sativus (Iridaceae), have been demonstrated. However, mechanisms of actions for purified constituents are greatly unknown. Objective: To examine the effects of Safranal, a main constituent of Saffron stigma, on cell viability and cytokine profile of peripheral blood mononuclear cells (PBMC) were examined. Methods: Effects of Safranal at 0.1, 0.5 and 1 mM concentrations were evaluated on cell viability and production of interleukin 4 (IL-4), IL-10 and interferon-γ (IFN-γ) from non-stimulated and phytohemagglutinin (PHA) stimulated PBMCs, compared to 0.1 mM dexamethasone and saline. Results: In stimulated cells, different concentrations of Safranal caused significant decrease of lymphocytes viability (p<0.001 for all concentrations). All concentrations of Safranal inhibited IFN-γ and IL-10 secretion in stimulated cells (p<0.01). In addition, high concentration of Safranal significantly decreased cell viability of non-stimulated PBMCs (p<0.001). The effect of 1 mM Safranal on IL-4 secretion was less than dexamethasone (p<0.05). Safranal showed a stimulatory effect on IFN-γ secretion in non-stimulated cells. The IFN-γ/IL-4 ratio at the presence of two higher Safranal concentrations both in non-stimulated and stimulated cells were significantly higher than those of control and PHA stimulated groups, respectively (p<0.05). Conclusion: The IFN-γ/IL-4 ratio increases in the presence of Safranal which indicates an effect on Th1/Th2 balance. Therefore, Safranal may have therapeutic effects in inflammatory diseases associated with Th1/Th2 imbalance.