Plants are important sources of crude medicines. The World Health Organization (WHO) estimates that 80 percent in the developing countries of the world obtain health care through traditional medicine, which utilizes herbal preparations to a high degree. Hard evidence on the extent to which active agents derived from higher (flowering) plants are used as drugs is difficult to project on a global basis. We do know that in the United States, about 25 percent of all prescriptions dispensed over the past three decades have contained active ingredients that are still extracted from higher plants. In 1981, the last year for which data have been calculated, the American public paid more than $12 billion for prescriptions containing active substances from higher plants.
It is also recognized that more than 120 drugs of known chemical structure, obtained from higher plants, are currently used on a global basis [see table]. Most of these have been synthesized in the laboratory, but only about six are produced entirely by synthetic procedures. The remainder are still extracted commercially from plants.
Traditional Medicines
South American Indians, Jesuit priests, Catholic missionaries, and Spanish conquerors as early as the mid-1600s told of the reduction of fever and relief of symptoms of what we now know to be malaria following ingestion of a brew of "Peruvian bark"--any one of several species of the genus Cinchona. The bark was brought to Europe in about 1645 and, after a period of time, became highly acclaimed as a treatment for malaria. It was not until 1820 that two French pharmacists. Pierre-Joseph Pelletier and Joseph-Bienaime Caventou, discovered that the active principle in the bark of Cinchona species was quinine, an extremely effective antimalarial and fever-reducing drug, Even today, quinine is an extremely important drug for treatment of drug-resistant malaria. It was discovered in a country where the plant source did not exist, and only because of undocumented claims that brews of its bark would reduce fever and alleviate the symptoms of malaria.
The discovery of quinine underscores the importance of investigating plants that have a history of medical use by indigenous peoples. In fact, 74 percent of today's plant-derived drugs were discovered because a scientific study was commissioned to examine folkloric claims about plants and to investigate the substance responsible for the alleged effects.
Traditional medicine systems, such as the Ayurvedic and Unani systems in India and the traditional Chinese medicine system, are thus of great interest to scientists. [See "Ayurveda: India's Life Science," THE WORLD & I, February 1988.] Variations of these systems are practiced in many other countries of the world, moreover. In Central and South America there are no organized systems of traditional medicine, but medicine is practiced by the shaman, the curandero, and others; in Africa, it is the traditional healer (in earlier days, the witch doctor). These systems have been used for centuries, and botanists, anthropologists, and others have studied both the systems and their practitioners.
Much information remains to be documented, however, and time is running out. As "modern" man pushes further and further into the so-called primitive jungles of the world, Western ideas and cultures take over. The medicine man is
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