Anticonvulsant Properties and Bio-Guided Isolation of Palmitone from Leaves of Annona diversifolia ¹

Abstract

The activity-guided fractionation of the ethanol extract of leaves of Annona diversifolia Saff., led to the isolation of palmitone (16-hentriacontanone) as the only anticonvulsant active compound. This aliphatic ketone was highly effective to diminish pentylenetetrazole (PTZ)-induced clonic-tonic seizures and toxicity. Also, it produced a prolongation of the latency for onset of seizures and a reduction of the death rate produced by 4-aminopyridine (4-AP) and bicuculline (BIC). However, it was inactive to inhibit the kainic acid (KA)- and strychnine (STC)-induced seizures. Palmitone did not produce motor incoordination and loss of righting reflex which are used as signs of neurological impairment. Palmitone (ED₅₀ = 1.85 mg/kg) proved to be a more potent antiepileptic drug against the PTZ-induced seizures than etosuximide (ED₅₀ = 59.6 mg/kg), sodium valproate (ED₅₀ = 63 mg/kg), and carbamazepine (ED₅₀ > 300 mg/kg) and it was only four-fold less potent than diazepam (ED₅₀ = 0.48 mg/kg). The pharmacological profile of palmitone suggests that this compound could be acting on the GABAergic inhibitory system.

Key words

Annona diversifolia - Annonaceae - 16-hentriacontanone - anticonvulsant - epilepsy - Mexican traditional medicine

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