Antihypoxic activities of Eryngium caucasicum and Urtica dioica

OBJECTIVE: Urtica dioica and Eryngium spp. have been used in traditional medicine for many years. In spite of many works, nothing is known about their protective effect against hypoxia-induced lethality. MATERIALS AND METHODS: Protective effects of U. dioica (UD) aerial parts and E. caucasicum (EC) inflorescence against hypoxia-induced lethality in mice were evaluated by three experimental models of hypoxia, asphyctic, haemic and circulatory. RESULTS: Statistically significant protective activities were established in some doses of extracts in three models. Antihypoxic activity was especially pronounced in polyphenol fractions in asphyctic model. EC polyphenol fraction at 400 mg/kg prolonged survival time (48.80 +/- 4.86, p < 0.001) which was comparable with that of phenytoin (p > 0.05). It was the most effective extract in circulatory model, too. It prolonged survival time significantly respect to control group (p < 0.001). UD extracts protected the mice but the response was not dose-dependent. In haemic model, extracts of EP significantly and dose dependently prolonged survival time as compared to control group (p < 0.001). At 600 mg/kg, EP was the most effective one, being capable of keeping the mice alive for 12.71 +/- 0.75 min. Only the concentration of 300 mg/kg of UD was effective (p < 0.001). CONCLUSIONS: Extracts showed remarkable antihypoxic effects. Pharmacological effects may be attributed to the presence of polyphenols in the extracts.