RESUMO
Extracts obtained from aerial parts of Stachys inflata have been used in Iranian folk medicine in infective, rheumatic and other inflammatory disorders. In the present study, the anti-inflammatory properties of total methanol extract isolated from aerial parts of Stachys inflata were investigated in two well-characterised inflammatory models in rats, carrageenan-induced paw oedema and formalin-induced paw licking. Intraperitoneal injection of the extract, 60 min before induction of inflammation, revealed a dose-related inhibition of carrageenan-induced rat paw oedema over the dose range 50-200 mg/kg. In the formalin test, the extract (50, 100 and 200 mg/kg) had no effect against the first phase (0-5 min) of the formalin-induced pain, but all three doses produced a significant blockade of the second phase (P < 0.001). Myeloperoxidase (MPO) activity was determined, and a histopathological study was carried out in paw tissue 4 h after induction of inflammation. The hydroalcoholic extract (200 mg/kg) substantially reduced MPO activity (P < 0.05), which was increased in the control group. Histological examination showed a marked reduction in tissue injury and inhibition in neutrophil infiltration in rats treated with the extract (200 mg/kg).