Natural Product Drug Discovery and Development

Abstract

Over the ages, humans have relied on nature for their basic needs for the production of foodstuffs, shelters, clothing, means of transportation, fertilizers, flavors and fragrances, and not least, medicines. Plants have formed the basis of sophisticated traditional medicine systems that have been in existence for thousands of years in countries such as China1 and India.2 These plant-basedsystems continue to play an essential role in health care, and it has been estimated by the World Health Organization that approximately 80% of the world’s inhabitants rely mainly on traditional medicines for their primary health care.3 Plant products also play an important role in the health care systems of the remaining 20% of the population mainly residing in developed countries. Analysis of data on prescriptions dispensed from community pharmacies in the United States from 1959 to 1980 indicates that about 25% contained plant extracts or active principles derived from higher plants, and at least 119 chemical substances, derived from 90 plant species, can be considered as important drugs currently in use in one or more countries.3 Of these 119 drugs, 74% were discovered as a result of chemical studies directed at the isolation of the active substances from plants used in traditional medicine. Well-known examples of plant-derived medicinal agents include: the antimalarial drug quinine, obtained from the bark of Cinchona officinalis; the analgesics, codeine and morphine from Papaver somniferum; the antihypertensive reserpine from Rauwolfia serpentina; and the cardiac glycoside, digoxin, from Digitalis purpurea.4