Pharmacological Studies on Substances of Plant Origin with Coronary Dilatating and Antiarrhythmic Action

Abstract

Studies were made of the action of biologically active substances isolated from medicinal plants on the coronary circulation under normal conditions and under conditions of induced coronary insufficiency, as well as on models of rhythmic disturbances provoked by different methods. The substances tested were: iridoid Oleuropein isolated from the olive leaves (Olea europaea); valepotriatic fraction V pt2 isolated for the valerian roots (Valeriana officinalis), all the flavonoids named crataemon and the hyperoside isolated from it, obtained from the flowers and leaves of hawthorn (Crataegus monogina); and all the furocoumarines named peucordin isolated from Peucedanum officinale. The results of these studies suggest that oleuropein, the valepotratic fraction, carataemon, hyperoside, and peucordin produce a clear-cut coronary dilatory action. The coronary flow of a rabbit heart isolated after the method of Langendorf was found to increase by more than 160% by crataemon (2×10-5), hyperoside (1×10-5) and peucordin (2×10-5) and more than 50% by oleuropein and the valepotriatic fraction. This effect of cratemon, hyperoside, and peucordin showed them to be superior to prenylamine. The coronary dilatory effect was also evaluated in experiments on whole organism (cats). It was found that in a dose of 10 mg/kg, peucordin increased the coronary flow by 82% hyperoside by 47%; crataemon, by 37% and the valepotriatic fraction, by 30%. The natural substances tested also eliminated induced pituitrin coronary spasm (experiments on unanaesthetized rabbits). Some of these substances showed a marked antiarrhythmic action, too. Oleuropein was active against BaCl2-induced arrhythmia (in rabbits) and against calcium-induced arrhythmia (in rats); it weakened the aconitine-induced arrhythmia. Crataemon also exerted a clear-cut effect on some kinds of induced arrhythmia. Crataemon and peucordin decrease oxygen utilization in the myocardium.