Suppression of neutrophil recruitment in mice by geranium essential oil

Background: In aromatherapy, essential oils are used as anti-inflammatory remedies, but experimental studies on their action mechanisms are very limited. Aims of the study: To assess their anti-inflammatory activities, the effects of essential oils on neutrophil recruitment in mice were examined in vivo. Method: The effect of essential oils on leukocyte and neutrophil recruitment induced 6 h after intraperitoneal injection of casein in mice was examined. Results: Leukocyte recruitment into the peritoneal cavity in mice was suppressed by intraperitoneal injections of geranium, lemongrass and spearmint oils at the dose of 5 mul/mouse, but was not by tea tree oil. This recruitment was inhibited dose-dependently by geranium oil. The suppression of leukocyte recruitment resulted from inhibition of neutrophil accumulation. Conclusion: Some essential oils used as anti-inflammatory remedies suppress neutrophil recruitment into the peritoneal cavity in mice.