Anticonvulsant activity of Citrus aurantium blossom essential oil (neroli): involvment of the GABAergic system.

Citrus aurantium L. blossoms are an important medicinal plant part in Iran and some other countries. It is used in traditional medicine as an antiseizure and anticonvulsant natural agent. Early in vitro research of the anticonvulsant activity of the blossom extracts were done but there has been no investigation focused on the blossom essential oil and its anticonvulsant activity. The anticonvulsant activity of the essential oil of C. aurantium blossoms (neroli) was investigated. The anticonvulsant activity of neroli was assessed in pentylenetetrazole (PTZ)-induced convulsion by i.v. and i.p. methods and maximal electroshock (MES) in mice, with diazepam as the standard drug. While mechanistic studies were conducted using flumazenil, a GABA A-benzodiazepine receptor complex site antagonist. Neroli produced protection against clonic by i.v adminiatration of PTZ at 20 and 40 mg/kg, compared with protection with benzodiazepine. The mean onset and percentage protection against convulsion in neroli-treated mice were reduced by flumazenil. Intraperitonaeal PTZ also decreased the latency of clonic seizure in the neroli (40 mg/kg) treated group. We also showed that neroli (20 and 40 mg/kg), exhibited inhibition of the tonic convulsion induced by MES and decreased the mortality rate. Neroli was analyzed by GC and GC-MS and twenty three constituents, representing 91.0 % of the chromatographical oil were identified. The major components of neroli were characterized as linalool (28.5%), linalyl acetate (19.6%), nerolidol (9.1%) E,E-farnesol (9.1%), α-terpineol (4.9%) and limonene (4.6%) which might be responsible for the anticonvulsant activity. The results suggest that neroli possesses biologically active constituent(s) that have anticonvulsant activity which supports the ethnomedicinal claims of the use of the plant in the management of seizure.