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

Scilla maderensis Menezes (Hyacinthaceae) is endemic to the Portuguese Arch ipelago of Madeira. The taxonomic proximity between Scilla L. and Urigena S teinh. genus, and also the knowledge that bulbs of Urginea maritima (L.) Ba ker (Scilla maritima L.) contain cardiac glycosides of the bufadienolide ty pe, led us to a phytochemical and pharmacological study of S. maderensis. E xtracts obtained from the bulbs were screened by TLC and tested in the isol ated 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 ef fect and toxic doses induced the arrest of the heartbeat in systole. We can conclude that the bulbs of S. maderensis contain substances exerting pharm acological effects on the heart. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.