Botanicals and chronic diseases: Presentation summary

Plants have been important in healing human disease for millennia. Herbal medicines have served human cultures worldwide, and have also been important sources of modern pharmaceuticals. Specific phytochemical groups from higher plants have been the sources of the bulk of natural product drugs used in biomedicine (Raskin et al., 2002). The plant-derived alkaloids that are widely used as drugs include atropine and the related hyoscyamine and scopolamine; camptothecin (used in synthesizing important cancer chemotherapeutics); cocaine; codeine, morphine, and other opiates; colchicine; emetine; galanthamine; nicotine; physostigmine; pilocarpine; reserpine; tubocurarine; quinidine and quinine; vinblastine and vincristine; and yohimbine. Important plant-derived terpenes and steroids include artemisinin; diosgenin, hecogenin, and stigmasterol, used in synthesis of important steroid drugs; taxol and other taxoids, sources of cancer chemotherapeutics; and digoxin and digitoxin. Phenolics include the pervasive and versatile aspirin, podophyllotoxin (used in synthesis of the cancer drug etoposide), and sennosides A and B. Also important are mixtures and extracts that are licensed as pharmaceuticals, such as ipecac and senna. As important as plants have been in the history of drug development, they are currently losing the competition in discovery of new chemical entities for drug discovery. Because of novel approaches to sourcing of lead compounds, and also the political issues regarding use of genetic resources that have been raised by the Convention on Biodiversity, interest in plant-based bioprospecting among the large pharmaceutical manufacturers is significantly reduced. There has been an evolution in the sources of materials used for screening that has paralleled the evolution of screening technologies. While humans have been involved in what is essentially bioprospecting for at least 10,000 years, chemical synthesis as a source of potential drugs has been in use for 100 years; combinatorial chemistry has been used for the