Inotropic and lusitropic effects of Perilla frutescens (L.) Britton extract on the rabbit myocardium.

Common perilla (Perilla frutescens (L.) Britton) is a plant cultivated in many countries around the world. Although its immunomodulating and antioxidative properties are well known, there is a lack of data about the cardiotropic activity of the plant. The objective of this study was to determine the influence of Perilla frutescens extract on the myocardial contractility in vitro and as a food supplement in vivo.Rabbits of the experimental group were fed with a supplement of 100 mg/kg of Perilla frutescens extract for 14 days. Rabbits of control group were fed with ordinary food. The maximal mechanical activity of isolated myocardial preparations, obtained from the rabbits of both groups, was tested during the perfusion with Ringer's solution containing 5 microM of adrenaline and 4.5 mM of CaCl2. For the assessment of the direct influence of Perilla frutescens extract on the myocardial contractility in vitro isolated heart preparations were perfused with 0.01, 0.1, and 1.0 mg/ml of Perilla frutescens extract.The maximum force of isometric contraction, maximum velocity of force development, and maximum velocity of relaxation were higher among the atrial and ventricular preparations from the experimental group, as compared with the control group. Perfusion of the myocardial preparations with different concentrations of Perilla frutescens extract revealed slight dose-dependent increase in the parameters of contraction and relaxation.The consumption of Perilla frutescens extract as a food supplement leads to an increase in the contractility of the rabbit myocardium. Perilla frutescens extract in vitro had a dose-dependent positive inotropic and lusitropic effect on the rabbit myocardium.