Avaliação anticonvulsivante e pró-convulsivante de óleos essenciais de Lippia origanoides e Rosmarinus officinalis em ratos: um estudoeletrofisiológico

Abstract

Epilepsy is a neuronal disorder characterized by abnormal brain excitability, leading to seizures. Only about 66% of epileptic patients respond adequately to treatment with existing conventional anticonvulsants, making it necessary to investigate new antiepileptic drugs. The growing research on natural products and their pharmacological properties has become increasingly promising, particularly in the study of essential oils, already widely used in popular culture for the treatment of several diseases. The present studies evaluated the anti- and pro-convulsant effects of the essential oils of Lippia origanoides (LOEO) and Rosmarinus officinalis (EORO) in Wistar rats. We evaluated the essential oil of Lippia origanoides (LOEO) (100 mg/kg i. p.) in comparison with diazepam (DZP) (5 mg/kg i. p.) and the combined administration of these two substances to control seizures induced by pentylenetetrazole (PTZ) (60 mg/kg i. p.). This evaluation was carried out using 108 male Wistar rats, which were divided into two experiments. Experiment 1 – Behavioral evaluation and Experiment 2 – Electrocorticographic evaluation. With rosemary essential oil, we evaluated high doses in 54 Wistar rats, weighing between 180 and 200 g. The study consisted of three experiments: 1) behavioral monitoring of the animals after administration of 500 mg/kg i.p.; 2) electrocorticographic recordings after drug administration; 3) reaction to anticonvulsant drugs, where phenytoin, phenobarbital and diazepam (10 mg/kg i.p.) were administered. With LOEO, the animals presented a more intense decrease in respiratory rate when combined with LOEO + DZP. EEG recordings showed a reduction in firing amplitude in the groups treated with LOEO. Combined treatment with diazepam resulted in increased anticonvulsant effects, while with EORO, the results demonstrated an increase in the latency time for the onset of isolated clonic seizures without loss of the postural reflex. The animals showed a more intense decrease in respiratory rate when combined with LOEO + DZP. EEG recordings showed a reduction in firing amplitude in the groups treated with LOEO. Combined treatment with diazepam resulted in increased anticonvulsant effects. Treatment with LOEO was effective in controlling seizures, and its combination with diazepam may represent a future option for the treatment of difficult-to-control seizures, while treatment with EORO demonstrated an excitatory activity related to the reduction of GABAergic activity.