Effects of hydroalcoholic extract from aerial parts of the sterile stems of Stachys inflata on myocardial infarct size in rats

Recently a potent anti-inflammatory effect of hydroalcoholic extract of the aerial parts of the sterile stems of Stachys inflata has been reported. This study examined whether hydroalcoholic extract isolated from aerial parts of non-flowering stems of Stachys inflata (standardized to contain 4.5% caffeic acid derivatives) reduce myocardial infarct size arising from coronary artery occlusion (30min) and reperfusion (2 h) in anaesthetized rats. In addition, the extract was also tested on the incidence and severity of ischaemic arrhythmias. Infusion of the extract (1.35 mg/kg/min) 5 min before coronary artery ligation and for the duration of the ischaemic (30 min) and reperfusion (2 h) periods resulted in a marked (p<0.001) decrease in infarct size (from 48.2 1% in control to 29.3 2.7% in treated rats). However, an infarct size of 46.7 3.4% was seen with the higher dose of the extract (2.70 mg/kg/min). The extract had no effect either on the severity and incidence of ischaemic arrhythmias or on the blood pressure. These results suggest that the hydroalcoholic extract of aerial parts of Stachys inflata attenuates the infarct size following ischaemia and reperfusion without any effect on the cardiovascular system. Anti-inflammatory actions of the extract may play a major role in reducing the infarct size.