Protective effects of saffron and its active components against oxidative stress and apoptosis in endothelial cells

Abstract

In this study, we investigated the role of mitogen-activated protein kinase (MAPK) signaling pathways in mediation of the protective effects of saffron extract, saffron essential oil, safranal and crocin on bovine aortic endothelial cells against oxidative injury. The viability of cells in response to H₂O₂-induced toxicity (0.4, 2 and 10 mM) was measured using resazurin assay in the presence or absence of saffron extract (2-40 μg/ml), saffron oil (2-40 μg/ml), safranal (2-40 μM) and crocin (2-40 μM). Dichlorodihydrofluorescin diacetate was used as an indicator for the amount of reactive oxygen species (ROS) in cells at the same concentrations of samples as the former test. In addition, propidium iodide staining of the fragmented DNA was performed to measure the level of apoptotic cells by the application of 2-10 μM of crocin and safranal. Finally, the proteins involved in apoptosis were detected using western blotting at the concentration of 0, 2, 10 μM for crocin and safranal. The results indicated that all tested moieties improved viability and reduced ROS production in H₂O₂-treated cells (p < 0.001 compared to H₂O₂). In addition, a significant decrease in apoptosis (3-35%) was observed in the cells that were treated with crocin and safranal. The observed protective effects of crocin and safranal were associated with the activation of SAPK/JNK and inhibition of ERK ½ that are related to MAPK pathways. The antioxidant and anti-apoptotic activities of saffron and its ingredients in endothelial cells are mediated via MAPK signaling pathways and might be of therapeutic potential for endothelial dysfunctionalities.

Keywords: Crocin; Endothelial dysfunction; MAPK; Saffron; Safranal.