Evaluation of Cns Depressant and Analgesic Activities of the Methanol Extract of Piper Longum Linn. Leaves

Present study reports CNS depressant and analgesic activities of methanol extract obtained from the leaves of Piper longum L (MEPL). CNS depressant activity was evaluated by using open field and hole cross tests at doses of 250 and 500 mg/kg body weight while peripheral analgesic activity was evaluated by using acetic acid induced writhing method and formalin test respectively in rat model at 100 and 200 mg/kg body weight. The results of the statistical analysis showed that the plant extract had significant (p<0.01) dose dependent CNS depressant and analgesic activities. Locomotor activity and exploratory behavior of rats in hole cross and open field test were decreased in the test group comparing the control group indicating CNS depressant effect of the extract which was comparable with the standard drug diazepam. The extract also showed better analgesic effects at both doses characterized by reduction in the number of writhes in the acetic acidinduced writhing model and reduction of licking time in the formalin test when compared to the control group. The extract, at the dose of 200 mg/kg, exerted a maximum of 57.58% inhibition of writhing response and 58.8% inhibition was observed for reference drug Indomethacin. So, the present results suggest that the methanol extract of P. longum leaves possesses remarkable CNS depressant and analgesic activities. INTRODUCTION: Piper longum L. is very important for its medicinal values from ancient times to present day. Piper longum L. (Piperaceae), commonly known as “long pepper”, is a slender aromatic climber with perennial woody roots and numerous simple, ovate, cordate leaves. Flowers are yellow, in elongate spikes and the fruits are small, ovoid berries, shiny blackish green, embedded in fleshy spikes . It is widely distributed in the tropical and subtropical regions of the world, throughout the Bangladesh, China, Indian, Sri Lanka, Middle Eastern countries and the America. The fruits are used as spice and as a preservative in pickle. They have a pungent taste and cause salivation and numbness of the mouth . In the traditional medicine, mature spikes of female plants, thick stems, roots and leaves are extensively used in the treatment of bronchial diseases, dyspepsia, worms, amoebiasis and aphrodisiac agent. Pepper is an important drug capable of improving intellect and memory power and also to regain health dispelling diseases. It is reportedly acrid, hot, light, digestive, appetizer and tonic.