Analgesic and anti-inflammatory properties of hydroalcoholic extracts of Malva sylvestris, Carum carvi or Medicago sativa, and their combination in a rat model

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.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.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.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.