The effect of Solanum melongena L. hydro-alcoholic extract on chronic pain in male mice as compared with morphine

Nowadays, steroidal anti inflammatory and opioide analgesics are widely used to attenuate the chronic Pain. For achieving new analgesics, many investigations have been focused on understanding the antinociceptive effects of different ethnic medicinal plants. In this study, the effects of Solanum melongena L. extract on chronic pain is assessed and compared with morphine. This study was conducted as an experimental trial on 40 male mice, equally and randomly divided in to 8 groups. 15 minutes after intra peritoneal injection of the extract, morphine or saline, 25µl of 2.5% formalin was subcutaneously injected to left hind paw of each mouse. Immediately after this injection the animals were placed under a chamber on the formalin test observational set up. Then pain scores were ascribed to each mouse according to pain intensity expression every 15 seconds during 1 hour. Our findings showed that 1000mg/kg Solanum melongena extract was analgesic in the 1st (acute) and the 2nd (chronic) phases of formalin test. This effect was more prominent during 20 to 40 min. after formalin injection and the pain score was significantly less than control (p=000). The analgesic effect of this eggplant dose, didn’t show any significant difference with 4mg/kg morphine sulfate in this time period (P=0.146). According to our findings the hydro-alcoholic extract of Solanum melongena reduces chronic pain produced by formalin injection.