Carvacrol and Eugenol Differentially Stimulate Intracellular Ca²⁺Mobilization and Mitogen-Activated Protein Kinases in Jurkat T-Cells and Monocytic THP-1 Cells

Essential oils are a major active constituent found in many Chinese medicinal herbs. Here, we demonstrate that two components of essential oils, carvacrol and eugenol, dose-dependently trigger intracellular Ca2+ mobilization in Jurkat T-cells and THP-1 monocytic cells. Both carvacrol and eugenol are also capable of stimulating the active phosphorylation of the p38 subgroup of mitogen-activated protein kinases (MAPKs) in both cell types. However, carvacrol selectively activated the ERK subgroup in Jurkat T-cells, and stimulated the JNK subgroup in THP-1 monocytic cells. Eugenol treatment was not linked to ERK or JNK activation in either cell type. EC50 values for the induction of Ca2+ mobilization and MAPK activation were around 10 - 30 microM for both carvacrol and eugenol. Our results suggest that these essential oil components may act as effective agents to modulate the functions of immuno-responsive cells via different intracellular signaling pathways.