ANALGESIC AND ANTICONVULSANT EFFECTS OF EXTRACTS FROM THE LEAVES OF STRYCHNOS NUX VOMICA LINN.

摘要

Strychnos nux vomica belongs to the family Loganiaceae is a fleshy herbaceous plant used in the Indian traditional medicine as nervine stomachic, tonic, aphrodiasic, spinal stimulant, also respiratory and cardiac stimulant. In excessive doses, it is a virulent poison producing titanic convulsions1.In the present work, the analgesic effects of methylene chloride/methanol (1:1) (CH_2CI_2/ CH_3OH) extract and its hexane, methylene chloride (CH_2CI_2), ethyl acetate, n-butanol fractions and aqueous residue has been evaluated using acetic acid, formalin and pressure test. The anticonvulsant effects of the CH_2CI_2/CH_3OH extract were also investigated on seizures induced by pentylene tetrazole (PTZ 70 mg/kg), strychnine sulphate (STN 2.5 mg/kg) an thiosemicarbazide (TSC 50 mg/kg)CH_2CI_2/CH_3OH extract and its fractions, administered orally at the doses of 150 and 300mg/kg, exhibited protective effect of at least 30% on the pain induced by acetic acid. The CH_2CI_2 fraction at 300 mg/kg showed a maximal effect of 78.49%. The CH_2Cl_2CH_3OH extract and its CH_2CI_2 fraction at the doses of 150 and 300 mg/kg significantly reduced the first phase of pain induced by formalin while the second phase was completely inhibited. The CH_2CI_2 fraction produced more than 45% reduction in the sensitivity to pain induced by pressure. The CH_2CI_2/ CH_3OH extract of Strychnos nux vomica significantly increased the latency period in seizures induced by PTZ and significantly reduced the duration of seizures induced by the three convulsant agents. The extract protected 20% of animals against death in seizures induced by TSC and STN . These results suggest a peripheral and central analgesic activities as well as an anticonvulsant effect of the leaves of Strychnos nux vomica.