Analgesic effect of aqueous leaf extract of Coriandrum sativum in male rats with streptozotocin-induced diabetes

Introduction: Hyperalgesia is one of the symptoms of diabetic neuropathy and is considered as a major clinical complaint in these patients which could affect the quality of their life. Since attenuation of hyperalgesia is very important, in the present study the possible analgesic effect of aqueous extract of coriander was investigated in male rats with streptozotocin-induced diabetes using standard formalin test in both early (acute) and late (chronic) phases. Materials and Methods: Male albino Wistar rats (250-350 g) were used. They were randomly divided into three groups, i.e. control, diabetic and extract-treated diabetic. For induction of diabetes, streptozotocin (60 mg/Kg) was administered i.p. After one month, formalin test was conducted. Results: Pain sensation of diabetic rats in the second interval (5-10 min) of the acute phase of the formalin test is higher (P<0.001) in comparison with control group, while a less significant difference was found between control and extract-treated diabetic group (P<0.05). On the other hand, there was no significant difference between control and extract-treated diabetic groups regarding acute and chronic phases of the formalin test. Conclusion: It is concluded that i.p. administration of aqueous leaf extract of coriander at a dose of 100 mg/kg does not produce a significant analgesic effect using formalin test.