Objective: The aim of this study was to evaluate the analgesic and anti-inflammatory effects of the hydroalcoholic extracts of Malva sylvestris flowers or Carum carvi and Medicago sativa seeds, alone and in combination, which have been used in traditional Iranian medicine.
Methods: Male Wistar rats were divided into 6 treatment groups: distilled water, sodium salicylate (SS), M. sylvestris extract (600 mg/kg), C. carvi extract (600 mg/kg), M. sativa extract (300 mg/kg) and combined extract (including 300 mg/kg M. sylvestris and C. carvi extracts, and 150 mg/kg M. sativa extract). The formalin pain model was used to evaluate the antinociceptive effects of the treatments. For anti-inflammatory effect, acute (one hour after injection) and chronic (during a week after injection) paw inflammation was measured after subcutaneous injection of 2.5% formalin in the hindpaw. Finally, tissue samples from all groups were prepared for histopathological studies.
Results: The combined extract significantly inhibited the nociception in the acute phase of the formalin test (P < 0.001). In the chronic phase, all the extracts and SS had significant analgesic effect (P < 0.001). Analgesic activity of the combined extract was significantly stronger than SS (P < 0.01). In the acute inflammation model, M. sylvestris, C. carvi and the combined drug had significant inhibitory effects against paw edema (P < 0.05). All extracts, individually and in combination, significantly alleviated chronic paw inflammation (P < 0.01). The combined extract had much more anti-inflammatory activity than SS (P < 0.05). Histopathological results indicated improvement and reduction of inflammatory factors in the treatment groups.
Conclusion: M. sylvestris, C. carvi and M. sativa have analgesic and anti-inflammatory properties. Potentially, each of these extracts or a mixture of them might be a valuable alternative drug to control pain and inflammation.
Keywords: Analgesic; Anti-inflammatory; Carum carvi; Formalin test; Malva sylvestris; Medicago sativa.
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