Analgesic And Neuropharmacological Evaluation of Ethyl Acetate Extract from Kalanchoepinnata leaves

Abstract

The analgesic and Neuropharmacologycal activity of acetic acid extract of leaves of Kalanchoepinnata(Lam.) Pers. was evaluated using an acetic acid-induced gastric pain model in Swiss albino mice. The acetic acid extract of leaves of Kalanchoepinnata demonstrated significant dose-dependent analgesic activity at all the tested doses of 100, 200, and 400 mg leaf extract/kg body weight in mice. Even at the lowest dose of 100 mg/kg body weight, the analgesic activity of leaf extract was comparable to that of a standard analgesic drug, aspirin, administered at 200 mg/kg body weight. The highest inhibition of writhing induced by acetic acid (47.5%) was observed with a dose of400 mg leaf extract/kg body weight, which was much greater than the inhibition obtained with aspirin (38.4%). At the lower dose of 250 mg bark extract/kg body weight, there was a decrease in the number of writhings compared to controls, but the decrease was not significant. The results suggest that acetic acid extract of leaves of Kalanchoepinnataand chloroform extract of barks have activities and validates of folk medicinal uses in Bangladesh for treatment of pain. It was however more efficacious against picrotoxininduced seizure where protection was observed in about one-quarter of mice, an effect which indicates that k. pinnata aqueous extract might produce its central nervous system depressant action as consequence of its GABAergic and less importantly, glycinergic transmission, since picrotoxin is a selective GABAA receptor antagonist (Rang et al 1996) while strychnine antagonizes the inhibitory spinal cord and brainstem reflexes of glycine (Yemitan et al 2001).