Anticonvulsant Activity of 80% Methanol Leaf Extract and Solvent Fractions of Buddleja polystachya Fresen. (Buddlejaceae) in Mice

Abstract

Epilepsy is a chronic non-communicable disease characterized by recurrent seizures. According to 2019 WHO report, it affects about 50  million people globally and nearly 80% of them live in low-and middleincome countries. Current antiepileptic drugs have several limitations including lack of response in significant number of patients and intolerable adverse drug reactions. Buddleja polystachya Fresen. (Buddlejaceae) is a medicinal plant used for the treatment of epilepsy in Ethiopian traditional medicine, where the dried leaves are crushed, mixed with local alcoholic beverage and taken orally. Thus, this study was conducted to evaluate the anticonvulsant activity of the 80% methanol leaf extract and solvent fractions of B. polystachya in mice models of seizure. The dried and powdered leaves of B.  polystachya were extracted using cold maceration with 80% methanol (1:5 w/v), and the resulting crude extract was fractionated using chloroform and n-butanol to get chloroform, n-butanol and aqueous fractions. Anticonvulsant activities of B. polystachya crude extract and solvent fractions at doses of 100, 200 and 400 mg/kg were evaluated using pentylenetetrazol (PTZ) and maximal electroshock (MES)–induced seizures in mice (n = 6). In addition, motor coordination effects were assessed using rotarod test. Sodium valproate (200 mg/kg), phenytoin (25 mg/kg) and diazepam (5 mg/kg) were used as standards for PTZ, MES and rotarod tests, respectively. Distilled water or 2% tween 80 was used as negative control. All doses of the crude extract exhibited a significant (p < 0.001) anticonvulsant property in both PTZ and MES tests compared with negative control. Similarly, the n-butanol fraction exerted significant (p < 0.001) anticonvulsant effects in both seizure models. However, the chloroform fraction (200 and 400 mg/kg) showed a significant (p < 0.001) anticonvulsant effect in only PTZ-induced seizure model. The aqueous fraction was devoid of any anticonvulsant activity in both models. The crude extract and fractions did not exert any significant changes in motor coordination. Preliminary phytochemical screening of the crude extract and solvent  fractions revealed the presence of flavonoids, phenols, tannins, steroids, terpenoids and saponins. In conclusion, the results of this study indicated that the plant has a promising anticonvulsant activity and could be considered as a potential source to develop new  anticonvulsant drug.