Evaluation of central nervous system effects of Citrus limon essential oil in mice

The central nervous system (CNS) depressant and anticonvulsant activities of Citrus limon (L.) Osbeck, Rutaceae, essential oil (EO) were investigated in animal models. The EO (50, 100 and 150 mg/kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity of animals when compared with the control group, up to thirty days after the administration and the dose of 150 mg/kg significantly reduced the remaining time of the animals on the Rota-rod apparatus. Additionally, C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by pentylenetetrazole (PTZ). The administration of FLU (10 mg/kg, i.p.), GABAA-benzodiazepine (GABA-BZD) receptor antagonist, antagonized the effect of C. limon essential oil at higher dose. This C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by picrotoxin (PIC) at higher dose. In the same way, the anticonvulsant effect of the EO was affected by pretreatment with flumazenil, a selective antagonist of benzodiazepine site of GABAA receptor. These results suggest a possible CNS depressant and anticonvulsant activities in mice that needs further investigation.