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. 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+1 mg/kg naloxan intraperitonealy respectively. 50 |iil 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 Cinnamomum Zeylanicum extract is dose-dependent and is driven negatively through opioid receptors

[ effect of saliva officinalis hydroalcoholic extract on analgesic effect of morphine in rat]

There are some reports in Iranian traditional medicine concerning the anti-inflammatory effect of Saliva Officinalis [SO]. In the present study with the aim of decreasing analgesic dose of morphine, analgesic effect of different doses of SO hydroalcoholic extract alone and associated with morphine were evaluated by tail flick in rats. Analgesic effects of SO hydroalcholic extract at doses of 200, 400, 600, 800 and 1000 mg/kg, i.p. were investigated. Then the influence of these doses associated with analgesic dose of morphine [2.5 mg/kg] was evaluated. Rats were placed into restrainer and then transferred into the tail flick apparatus with the intensity 55§C and cut off time=10 sec. In order to verify the role of opioid receptors on analgesic effect of SO extract, naloxone [1mg/kg, i.p.] was administered to one group of rats 15 min before receiving 800 mg/kg extract. Then, the data were analyzed by two-way ANOVA followed by LSD post hoc test and significant difference between groups was accepted with P<0.05. The Data have shown that, the SO extract relieved pain in tail-flick test dose dependently and the most effective dose was 800 mg/kg. The maximum analgesic effect of the extract combined with morphine was observed at time point 45 min. Naloxane, opioid receptor antagonist could reduce analgesic effect of the extract. On the basis the results obtained in this study, it could be suggested that the SO extract potentiates morphine antinociceptive effect and this means that the opioid system may be involved in the analgesic effect of this plant extract