Studies on Cardio-Active Crude Drugs; I. Effect of Coumarins on Cultured Myocardial Cells

Using cultured embryonic myocardial cells, the effects of naturally occurring coumarins with various types of structures on the beating activity were studied. Coumarins isolated from Angelica decursiva Fr. et Sav., Umbelliferae, decursinol and nodakenetin, as well as dicoumarol, one of the known anticoagulants, remarkably decreased beating rate of the cells. The inhibitory effect on the beating rate was in parallel to calcium uptake, suggesting that the inhibition of myocardial cell beating was due to blocking of calcium influx.