Analgesic effect of hydroalcoholic extract of Zingiber and piper nigrum in mice by tail-flick test

in traditional medicine,some plants have been used as analysics.the aim of this investigation was to evaluate the analgesic effect of two plants,piper nigrum and Zingiber officinale that are used  traditionally to relieve headache,rheumatic arthritis,and toothache.for this purpose the methanolic extract of zingiber and piper nigrum,in different doses,were injected intraperitonealy to mice and the analgesic effect was determined by tail-flick apparatus.the results show that the suxhleted extract of piper nigrum with dose of 50 and 75 mg/kg of body weight did not induce significant analgesia in comparison to the control group but of 100mg/kg induced significant analgesia.this analgesia effect was maximum at 90 min after injection of the extract (p<0.01).the analgesia response fron this dose was also significant at 15 (p<0.05) 30,45 and 60 min after the injection (p<0.01) compared to the control group.injection of the perulated extract and this difference to analgesia effect between the two extracts was maximum at 90min post-injection(p<0.01).the difference to analgesia effect was also significant at 30 min.(p<0.01) and 60min after injection (p<0.05).the results from the experiment of zingiber showed that the injection of perculated extract of zingiber to mice with doses of 50,75 and 100 mg/kg induced significant analgesia at 30,45,60 min(p<0.01) and 90min (p<0.05) post-injection in comparison with the control group.this response reached maximum at 45 min post-injection and reduced there after.injection of suxhleted extract with doses of 100mg/kg induced lower analgesic effect than the same dose of perculated extract at 45 min after the injection(p<0.01).at the other times,analgesic responses between the extracts were not significantly different.