The study of analgesic effect of licorice root extract in rat

Although non-steroidal anti-inflammatory drugs (NSAIDs) and opioid compounds are widely used in the releif of pain, they are not always useful due to their side effects. It seems necessary to search for newer analgesic compounds. Therefore, we decided to study the analgesic effects of this plant. For extraction, percolation method was used and different weights of dried extract were dissolved in normal saline to produce desired concentration. The extract was injected intraperitoneally (mg/kg/2 ml). Two methods -the tail flick test for acut pain and the formalin test for chronic pain- were employed to measure pain Different doses of licorice root extract induced analgesia in the second phase of formalin test but it did not analgesic effect in tail flick test. The anti-nociceptive effect of licorice root extract is similar to non-steroidal anti-inflammatory drugs.