Evaluation of Analgesic Activities of 80% Methanol Leaf Extract of Solanum incanum L. (Solanaceae) in Mice

Abstract

Solanum incanum Linnaeus is traditionally used for treatment of pain and other ailments. But there is no scientific evidence on its analgesic activity to-date. Thus the aim of this study was to evaluate the analgesic activities of 80% methanol leaf extract of S.incanum in mice. After extraction of the crude using 80% methanol, S.incanum extract was evaluated for analgesic activity in hot plate test and acetic-acid induced writhing test. Mice were randomly assigned to different groups and treated with 100, 200 and 400 mg/kg doses of the extract and reference control groups (morphine 5mg/kg and Aspirin 150 mg/kg) and negative control were treated with 2% tween 80. In the hot-plate method, all doses of the extract and the standard drug of morphine prolonged the reaction time significantly (p<0.05, or p<0.01 or p<0.001) as compared to negative control throughout the observation period. Prolongation of reaction time produced by 100mg/kg of the extract was lower (p<0.01) compared to morphine, 200mg/kg, and 400mg/kg at 90 and 120 min. However, middle and higher dose exerts comparable result at 30, 60 and 90and 120 min in relation to the standard drug. In addition 80% methanol extract of S.incanum showed a significant protection (p<0.05) against acetic acid induced writhing compared to negative control. The extract produced a significant analgesic activity with 55.6, 38.2 and 44.8% inhibition of number of writhing at 100, 200 and 400 mg/kg dose levels, respectively. In conclusion, this study clearly suggests that 80% methanol leaf extract of S. incanum is endowed with central and peripheral analgesic activity. Hence, the findings collectively uphold the traditional use of the plant for pain treatment.

Keywords: Analgesic, S.incanum , Hot plate, Acetic acid