Study of Analgesic Effect of Hydroalcoholic Extract of Cinammom

The side effects due to application of synthetic analgesic drugs in the clinical practice have turned on researchers to focus on development of herbal medicine as more appropriate analgesic agents. The aim of this study was evaluation the analgesic effects of hydroalcholic extract of Cinnamomum Zeylanicum in comparison with morphine and aspirin. Materiales and For preparing the hydroalcoholic extract of Cinnamomum the maceration method was used. Wistar male rats were divided into eight groups of 6 rats, randomly and treated groups have received 200, 400, 600, 800 mg/kg extract and the two positive control groups received 2.5 mg/kg morphine or 300mg/kg aspirin. Negative control group received normal saline (5ml/kg) and an additional group also received 600 mg/kg extract+1mg/kg naloxan intraperitonealy respectively. 50 µl formalin 2.5% was injected in right hindpaw subcutaneously and analgesic behaviors were scored. The results revealed that the Cinnamomum Zeylanicum extract had analgesic effect as dose-dependent and its analgesic effective dose was 600 mg/kg. Our results showed that the analgesic effect of its best effective dose (600mg/kg) on acute pain was more than aspirin while it was less than morphine. Also the effect of extract on chronic pain was less than morphine and aspirin. There were no significant differences between analgesic effects of Cinnamomum Zeylanicum extract with naloxone or alone. We concluded that the analgesic effect of Cinnamo- mum Zeylanicum extract is dose-dependent and is driven negatively through opioid receptors.