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The Benefits of Studying Medicinal Plants and Ethnobotany (page 6)
by Kimberly Johnson, MD

Many of our most commonly prescribed medications are derived from plants.

Market Value and Concrete Examples

Attempts to estimate the economic value of plant-based drugs (the economic value of a drug includes the value of sales -- i.e. the market value -- plus the value of decreases in morbidity and mortality realized through its use, as well as the value of its contribution to public health and productivity) have been done; the benefits derived from saving lives of people afflicted with cancer in the U.S. has been estimated at $250 billion annually. Recent estimates predict that about 25% of the world's 250,000 species of flowering plants will be extinct by the year 2050. Based on assumptions made by an expert panel of drug development professionals of the probablility that any given plant would yield a new marketable prescription drug, one marketable drug will be lost in every 2 year period, between 1991 and 2050 (Principe, in Balick, Elisabetsky and Laird 1996).

Many of our most commonly prescribed medications are derived from plants. Some examples of plant-derived pharmaceuticals include the following:

Digitalis: The foxglove (Digitalis purpurea) is the source of digitalis. This medication was introduced into medical practice by a British physician in 1785. The derivative, digoxin, is one of the ten most commonly prescribed drugs in the US, used for the treatment of congestive heart failure and atrial dysrhythmias.

Taxol, the biggest recent advance in the treatment of breast and ovarian cancer, is derived from the bark of the Pacific Yew (Taxus brevifolia). This tree grows in the ancient forests of the Pacific Northwest and was considered an "understory weed" by foresters and routinely burned as trash during timber operations. Anti-cancer activity was discovered in a large-scale screening program in 1963 at the National Cancer Institute.

Artemisinin: Wormwood (Artemesia annua) Research professor Henry Lai and assistant research professor Narendra Singh, both bioengineering research professors at the University of Washington, have rediscovered annual wormwood (Artemesia annua) as a promising potential treatment for cancer among the ancient arts of Chinese folk medicine. Now the active compound, artemisinin, is the basis for a cancer-fighting pill.

Vincristine and vinblastine: The Madagascar rosy periwinkle (Catharanthus roseus) is the source of vincristine and vinblastine, used for chemotherapy of leukemia, Hodgkin's Disease, and breast and lung cancer. This plant first came to the attention of western scientists in 1952 because of the claims by traditional healers of its usefulness as a treatment for diabetes. When tested it had no anti-diabetic effects, but was found to cause severe bone marrow suppression. The active alkaloid constituents were isolated thereafter.

Ginkgo biloba, currently the most common drug used in Germany, stimulates peripheral and cerebral circulation, and is used to prevent dementia and memory loss. It became extinct in the wild thousands of years ago, but was saved by Chinese monks who planted it in their temple gardens. Echinacea stimulates the immune system and is used for colds and flu. It has been the subject of over 500 scientific studies and has been shown to enhance phagocytosis, activate macrophages, and enhance the ability of immune system cells to kill bacteria. Some species are rapidly disappearing from the wild due to overcollection, but it is now being cultivated as a valuable cash crop.

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References on this page:

Balick, M.J., E. Elisabetsky, and S. Laird, eds. 1996. Medicinal Resources of the Tropical Forest: Biodiversity and its Importance to Human Health. New York: Columbia University Press.
Articles by authors in the above text:

Tuxill, J. 1999. Nature's Cornucopia: Our Stake in Plant Diversity. Worldwatch Paper 148. Worldwatch Institute, Washington DC.

Farnsworth, N.R. and D.D. Soejarto. 1985. Potential consequence of plant extinction in the United States on the current and future availability of prescription drugs. Economic Botany 39 (3):231-40.

Farnsworth, N.R. et al. 1985. "Medicinal plants in therapy." Bulletin of the World Health Organization. 63 (6): 965-81.