The Effect of Geum kokanicum Total Extract on Formalin-Induced Pain in Male Mice

As a result of adverse side effects caused by NSAIDs and opiates, the use of these drugs has not been successful in all cases. Therefore, new analgesic drugs lacking those effects are being searched. Due to the anti- nociceptive effects of tanan and flavonoid compounds present in Geum kokanicum, we evaluated its anti-nociceptive effects by administrating a formalin test. In this research NMRI male mice were used. After determining LD50 in Geum kokanicum total extract, different doses of the extract were intraperitoneally injected into the mice and then its anti-nociceptive effect was estimated by formalin test. The mice were divided into six groups: two groups of control and positive control which received morphine 10 mg/kg and the other four groups which were given the extract in doses of 0.025, 0.05, 0.1 and 0.2 gr/kg. Also TLC chromatography was done for finding the extract constituents. The data were analyzed using one-way ANOVA followed by Tukey-kramer multiple comparison test. The extract LD50 used for this study was determined as 1gr/kg. The findings indicate that total extracts of 0.5, 0.1 and 0.2 gr/kg doses have particular anti-nociceptive effects, as compared with the control groups. The extract of 0.2 gr/kg was found to be the most effective although the difference with positive control was not significant. Also, TlC chromatography indicated the presence of steroid and triterpenes in this plant. The results showed that extract of Geum kokanicum can inhibit nociceptive effects in the first and second phases of pain; i.e. acute and chronic pains, respectively. In particular, the antinociceptive effect in high doses is the same as morphine, a strong analgesic substance. This effect may be due to presence of steroid and triterpenes in this plant.