Influence of Crocetin, a Natural Carotenoid Dicarboxylic Acid in Saffron, on L-Type Ca2+ Current, Intracellular Ca2+ Handling and Contraction of Isolated Rat Cardiomyocytes.

Crocetin is a major bioactive ingredient in saffron (Crocus sativus L.) and has favorable cardiovascular effects. Here, the effects of crocetin on L-type Ca2+ current (ICa-L), contractility, and the Ca2+ transients of rat cardiomyocytes, were investigated via patch-clamp technique and the Ion Optix system. A 600 µg/mL dose of crocetin decreased ICa-L 31.50 ± 2.53% in normal myocytes and 35.56 ± 2.42% in ischemic myocytes, respectively. The current voltage nexus of the calcium current, the reversal of the calcium current, and the activation/deactivation of the calcium current was not changed. At 600 µg/mL, crocetin abated cell shortening by 28.6 ± 2.31%, with a decrease in the time to 50% of the peak and a decrease in the time to 50% of the baseline. At 600 µg/mL, crocetin abated the crest value of the ephemeral Ca2+ by 31.87 ± 2.57%. The time to half maximal of Ca2+ peak and the time constant of decay of Ca2+ transient were both reduced. Our results suggest that crocetin inhibits L-type Ca2+ channels, causing decreased intracellular Ca2+ concentration and contractility in adult rat ventricular myocytes. These findings reveal crocetin's potential use as a calcium channel antagonist for the treatment of cardiovascular disease.