Foeniculum vulgare Mill. increases cytosolic Ca2+ concentration and inhibits store-operated Ca2+ entry in vascular endothelial cells

Abstract

This study assessed the effects of essential oil of Foeniculum vulgare Mill. (fennel oil) and of transanethole, the main component of fennel oil, on extracellular Ca2+-induced store-operated Ca2+ entry (SOCE) into vascular endothelial (EA) cells and their mechanisms of action. Components of fennel oil were analyzed by gas chromatography-mass spectrometry. Cytosolic Ca2+ concentration ([Ca2+](c)) in EA cells was determined using Fura-2 fluorescence. In the presence of extracellular Ca2+, fennel oil significantly increased [Ca2+](c) in EA cells; this increase was significantly inhibited by the Ca2+ channel blockers La3+ and nifedipine. In contrast, fennel oil induced [Ca2+](c) was significantly lower in Ca2+-free solution, suggesting that fennel oil increases [Ca2+](c) mainly by enhancing Ca2+ influx into EA cells. [Ca2+](c) mobilization by trans-anethole was similar to that of fennel oil. Moreover, SOCE was suppressed by fennel oil and trans-anethole. SOCE was also attenuated by lanthanum (La3+), a non-selective cation channel (NSC) blocker; 2-aminoethoxydiphenyl borane (2-APB), an inositol 1,4,5-triphosphate (IP3) receptor inhibitor and SOCE blocker; and U73122, an inhibitor of phospholipase C (PLC). Further, SOCE was more strongly inhibited by La3+ plus fennel oil or trans-anethole than by La3+ alone. These findings suggest that fennel oil and trans-anethole significantly inhibit SOCE-induced [Ca2+] c increase in vascular endothelial cells and that these reactions may be mediated by NSC, IP3-dependent Ca2+ mobilization, and PLC activation. (C) 2016 Elsevier Masson SAS. All rights reserved.