Cardiovascular activity of a methanolic extract of Digitalis purpurea spp. heywoodii

The paper deals with the effects of a glycosidal extract of Digitalis heywoodii, ssp. of Digitalis purpurea L., (Schrophulariaceae) grown in Badajoz (Spain), on isolated cardiac auricle of rabbits, urinary excretion of rats, as well as its emetic effect in pigeons. These effects using vehicle (propylene glycol-ethanol-water, 40:10:50) and digoxin as standards are presented. The extract at concentrations of 20 and 40 microg/ml produced an increase in the contraction force of auricles in a dose-dependent way. At doses of 15 and 30 mg/kg a slight diuretic and natriuretic effect was observed. The active dose range for emesis was 0.5-4 mg/kg and a decrease of the emesis time within 10 min of injection in dose-dependent manner was obtained. The pharmacological activity of the extract is related to gitoxin derivatives (digitalinum verum and strospeside), the most abundant compounds obtained from the leaves of Digitalis purpurea spp. heywoodii.