Effects of essential oils on the inflammatory response of vascular endothelial cells

Abstract

Essential oils have protective effects on various inflammatory conditions such as allergies and acute inflammation. To determine the characteristics of essential oils on anti-inflammatory effects, we focused on the basic process of type I allergy such as hay fever and evaluated how these oils suppress nitric oxide (NO) production in human umbilical vein endothelial cells (HUVEC) induced by calcium ionophore (A23187). We selected six essential oils commonly used in aromatherapy for allergies such as hay fever. Then, we added each of the essential oils and A23187 on a plate with densely cultured HUVECs, cultured them for 50 min, and measured the amount of NO secreted into the culture medium. Tea tree oil and lemongrass oil demonstrated the strongest inhibitory effect at 0.001%, followed by geranium oil and lavender oil; conversely, chamomile oil and eucalyptus oil had no significant inhibition. On comparing the suppressive activity on other basic processes of inflammation, such as neutrophil activation, we found that these essential oils may have different mechanisms of action on various inflammatory responses. Comparing the effects of essential oils on various basic processes of inflammation-related reactions and clarifying their mechanisms of action might help establish a theoretical basis for proposing combinations and uses of essential oils for the treatment of inflammatory conditions.