April, 2000: India
Called "chotachand" in Hindi, the snakeroot plant is the source of a local Indian myth. This ancient Hindu legend claims that when a mongoose was about to engage in combat with a cobra, the mongoose would feed on the roots of the snakeroot plant. Then, if bitten during the battle, the mongoose would be unaffected by the cobra's venom. The snakeroot plant thus became known to the locals as a potent antidote for snakebites. If this fable is true, the use of this plant can serve as an example of "zoopharmacognosy," a term coined in 1992 to describe the study of how animals use and recognize medicinal plants. The term originates from the Greek roots zoo -, "animal"; pharma-, "drug or poison," and -cognosy, "to recognize."
The practices of ancient Hinduism, or Vedanta, have been in use since 1500—1000 B.C. These systems of philosophy form the basis for the better known Ayurveda, which also began in India. Ayurveda is a holistic system of healing devoted to establishing and maintaining a balance between the life energies within us rather than focusing on individual symptoms. The snakeroot plant has been a part of Ayurvedic medicine for thousands of years.
Rauvolfia serpentina. (Photo © 1999 Erica Kipp.)
|
The snakeroot plant is scientifically known as Rauvolfia serpentina. It belongs to the Apocynaceae, a family of dicots that is pantropic in distribution, with only a few representatives in temperate zones. Some species within Apocynaceae have buttressed roots and are found in the tropical rain forests of India and Malaya. However, most species, such as Rauvolfia, are evergreen shrubs and trees. They tend to have simple, entire leaves, and most of their plant parts contain a milky latex. Some species have solitary flowers, while others have raceme, or most commonly, cyme inflorescences. (An inflorescence is a group of flowers attached to a common axis.) The flowers are bisexual (having both male and female reproductive organs) and are often showy and fragrant.
In addition to its use as an antidote for snakebites, R. serpentina was often employed to treat anxiety, insomnia, and insanity. In fact, in parts of India, R. serpentina was known as "pagal-ka-dawa," which translates to "the insanity cure." Other local cultures used the plant as a relaxant and as a tranquilizer to put children to sleep for the night.
|
|
Technician removing the apical meristem from a plant to be cultured. (From Stern, Introductory Plant Biology, 8th edition, © 2000, McGraw-Hill Companies, Inc.)
Plants that have developed from the cultured meristematic tissue. They will be separated and further cultured to maturity. (From Stern, Introductory Plant Biology, 8th edition, © 2000, McGraw-Hill Companies, Inc.)
In 1949, the alkaloid reserpine was isolated and identified from the roots of Rauvolfia. Alkaloids are a major class of natural products that have a physiological effect in other organisms. They characteristically contain carbon, hydrogen, nitrogen, and in many cases, oxygen. Because of their potent pharmacological effects, alkaloids are the basis for many pharmaceuticals. Reserpine is considered a sympathomimetic agent, one that targets the sympathetic nervous system. Reserpine has been found to lower blood pressure in remarkably low oral doses. CIBA, a pharmaceutical company based in Switzerland, marketed reserpine under the trade name Serpasil as the first major drug to treat hypertension. (In 1996, CIBA combined with Sandoz Pharmaceuticals, another Swiss company, and now exists under the new name Novartis.)
Although reserpine has been successfully synthesized, natural versions are less expensive and therefore more desirable. As a result, high-volume collection of R. serpentina is depleting the plant as a natural resource. A protocol for mass artificial propagation of R. serpentina has been proposed by Jahangirnagar University in Bangladesh. Cell tissue culture is a technique whereby a mass of undifferentiated cells called a "callus" is maintained indefinitely on an artificial medium. The proposed protocol suggests preparing in vitro cultures with shoot tips and lateral buds, both areas where an apical meristem is present. Although the tissue culture can be initiated with almost any plant part, the best results are produced with tissue taken from the apical meristem region.
One advantage of tissue culture is the ability to grow large numbers of cells in smaller spaces while maintaining sterile conditions and a controllable laboratory environment. If cell culturing R. serpentina achieves new growth and allows researchers to obtain the alkaloid reserpine, native populations of the snakeroot plant should be left undisturbed.
References, Websites, and Further Reading
Balick, M.J., and P.A. Cox. 1996. Plants, people, and culture: The science of ethnobotany. New York: Scientific American Library.
Heywood, V.H. 1993. Flowering plants of the world. New York: Oxford University Press.
Mabberley, D.J. 1997. The plant-book. 2d edition. New York: Cambridge University Press.
Information on Ayurvedic medicine.
Stern, Introductory Plant Biology, 8th Edition
Chapter 2: The Nature of Life
Chemical and physical bases of life, pp. 15—18
Lipids, p. 23
Chapter 5: Roots and Soils
Buttress roots (including photograph), pp. 72—73
Chapter 6: Stems
Latex, pp. 92—93
Chapter 8: Flowers, Fruits, and Seeds
Differences between dicots and monocots (including palm growth pattern), p. 129
Chart comparison of dicots and monocots, p. 130
Chapter 14: Plant Propagation and Biotechnology, pp. 237—54
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
If you have a question or a problem about a specific book or product, please fill out our Product Feedback Form.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com
or let us know what you think by filling out our Site Survey.
