Scilla maderensis, TLC screening and positive inotropic effect of bulb extracts.

Scilla maderensis Menezes (Hyacinthaceae) is endemic to the Portuguese Archipelago of Madeira. The taxonomic proximity between Scilla L. and Urginea Steinh. genus, and also the knowledge that bulbs of Urginea maritima (L.) Baker (Scilla maritima L.) contain cardiac glycosides of the bufadienolide type, led us to a phytochemical and pharmacological study of S. maderensis. Extracts obtained from the bulbs were screened by TLC and tested in the isolated frog heart preparation. The TLC screening revealed spots with colours and R(f) values similar to those obtained for proscillaridin and scillaren A. In the frog heart preparation the extracts showed a positive inotropic effect and toxic doses induced the arrest of the heartbeat in systole. We can conclude that the bulbs of S. maderensis contain substances exerting pharmacological effects on the heart.