Isolation of oleanolic acid from Parinari curatellifolia (Planch Ex. Benth) stem bark and evaluation of its anticonvulsant and sedative activities in rodents

Abstract

Parinari curatellifolia is used by traditional medicine practitioners for the treatment of epilepsy. So far, no study has isolated the active principle that may be responsible for its anticonvulsant activity. The study aimed to isolate compound(s) present from Parinari curatellifolia that may be responsible for its anticonvulsant activity. The ethyl acetate fraction of the stem bark of Parinari curatellifolia was chromatographed over silica gel column chromatography which led to the isolation of compound C. The structure of the compound was elucidated using IR, 1H-NMR, 13CNMR and DEPT-135 spectroscopy. Acute toxicity study of the isolated compound was evaluated in mice using OECD 425 guidelines (2000 mg/kg orally). The anticonvulsant study of the isolated compound (at 50, 75 and 100 mg/kg) was evaluated in mice using pentylenetetrazole (PTZ)- induced convulsion. The sedative properties of the compound (at 10, 50 and 100 mg/kg) were evaluated using the diazepam-induced sleep model in rats. Structure elucidation of the isolated compound confirmed the compound to be oleanolic acid. Acute toxicity study revealed no lethal effects at 2000 mg/kg. the compound (oleanolic acid) significantly (p<0.05) increased the onset of seizure at all doses and resulted in 25% protection against seizure at 100 mg/kg. It exerted sedative effect at all doses by significantly (p<0.05) reducing sleep latency and increasing total duration of sleep induced by diazepam. The results obtained from this study have revealed the presence of oleanolic acid in P. curatellifolia and have shown its anticonvulsant and sedative activities for the first time.