Evaluation of the analgesic and anticonvulsant properties of the ethanol extract of Lannea acida leaves in mice
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Keywords

Pain
Epilepsy
Lannea acida

Abstract

Lannea acida A. Rich. (family: Anacardiaceae) is a multipurpose medicinal tree that is indigenous to several West African countries. It is used traditionally for the treatment of several ailments including pain and epilepsy. In this study, Lannea acida  leaf ethanol extract's analgesic and anticonvulsant effects are assessed using convulsion and pain models in animals. The phytochemical constituents of the ethanol extract of Lannea acida leaves (EELAL) as well as its acute oral toxicity were determined. Swiss mice weighing between 18-25 g were allotted to treatment groups (n = 5) and the analgesic property of EELAL at doses of 100, 200 and 400 mg/kg administered orally was evaluated using acetic acid-induced writhing test, formalin-induced paw licking test and hot plate test. The doses of 500, 750 and 1000 mg/kg were selected for the evaluation of the anticonvulsant activity of EELAL using pentylene tetrazole, strychnine and isoniazid-induced convulsion models. The results of the phytochemical studies showed that EELAL had an abundance of tannins and flavonoids, while the oral median lethal dose (LD50) was determined to be >2000 mg/kg. Acetic acid-induced abdominal constrictions were significantly inhibited by 100, 200 and 400 mg/kg, EEAL (58.20, 34.73 and 95.62%) compared with negative control animals. The inflammatory phase of the formalin test was significantly inhibited by EELAL. This was observed as the reduction in paw-licking time compared to normal saline-treated animals. The extract did not show any significant effect on the neurogenic phase of the formalin test, hot plate test and chemical-induced (pentylene-tetrazole, strychnine, and isoniazid) epilepsy tests. The leaves of Lannea acida  possess significant peripheral analgesic activity but lack an anticonvulsant effect.

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