The interest in nature as a source of potential chemotherapeutic agents continues. Natural products and their derivatives represent more than 50% of all the drugs in clinical use in the world today. Higher plants contribute no less than 25% of the total (Farnsworth et al., 1985; Cragg and Newman, 2005). In the last 40 years, many potent drugs have been derived from flowering plants; including for example Dioscorea species (diosgenin), from which all an ovulatory contraceptive agents have been derived; reserpine and other antihypertensive and tranquilizing alkaloids from Rauwolfia species; pilocarpine to treat glaucoma and ‘dry mouth’, derived from a group of South American trees(Pilocarpus spp.) in the Citrus family; two powerful anti-cancer agents from the Rosy Periwinkle (Catharanthus roseus); laxative agents from Cassia species and a cardiotonic agent to treat heart failure from Digitalis species (Newman et al.,2000).