Calcium channel blocking activity: Screening methods for plant derived compounds.

Calcium channel blockers are a heterogenous group of substances that inhibit influx of Ca(2+) into the cell. Their main therapeutical influence is on the function of heart and blood circulation. A vast number of pure natural compounds with calcium antagonistic activity, mainly coumarins, have been isolated from plants and identified. Screening natural products for calcium channel blockers has been done through classical in vitro aorta or ileum strip assays, but recently in vitro screens using animal cell lines also have been established. The number of in vivo assays on natural compounds is quite limited so far. Much more research is needed to clarify the basic pharmacology and to determine the possible clinical use of pure compounds discovered from plants.