THE CARDIOACTIVE SCREENING OF THE EXTRACT FROM THE BARK OF STROPHANTHUS CUMINGII A.DC. (APOCYNACEAE) USING ISOLATED FROG HEART

Maribeth R. Laurente*, Mafel C. Ysrael

Strophanthus cumingii A. DC. (Apocynaceae) is one of two endemic Strophanthus species in the Philippines the bark of which is used as an arrow poison ^[1]. Strophanthus species used for this purpose are known to contain cardiac glycoside strophanthin in the bark and seeds ^[2]. This study determined the cardioactivity of the bark extract S. cumingii and its sub-fractions on isolated frog hearts. The hexane fraction was the most cardioactive with a maximum of 30.58% increase in the force of contraction and 38.24% increase in the frequency of contraction. The non-polar fraction of the crude extract from the bark of S. cumingii elicited a positive inotropic and negative chronotropic effect on the isolated frog hearts.