March, 2002:Argentina
For centuries, the Guarani, a group of indigenous tribes of South America,
have consumed an infusion of Ilex paraguariensis leaves. The medicinal
properties of this plant, more commonly known as "yerba mate,"
include boosting the immune system, improving digestion, and stimulating
the memory. Scientific studies from as early as 1964 document the many
healing properties of yerba mate. Most recently, it has gained popularity
as a drink that satisfies nutrient requirements and can be added to many
commercial drinks as well. Additionally, since 1996, medical research
has been investigating the antioxidant properties of I. paraguariensis.
I. paraguariensis is a plant in the Aquafoliaceae family, commonly referred to as the holly family. Because these dicots require high temperatures, high humidity, and about 1,500 mm of annual rainfall for proper growth, they grow well in their native region, which ranges from Brazil to northeastern Argentina. A tea-like beverage made from the leaves of this evergreen is consumed in this area, where over 300,000 tons of tea leaves are produced annually. I. paraguariensis produces white flowers and red fruits. It has alternate phylotaxy, and more than 196 volatile chemicals have been isolated from it to date.
A 1964 study on the leaves of I. paraguariensis, performed by the Pasteur Institute and the Paris Scientific Society, concluded that this plant contains almost all the nutrients necessary to sustain life. Based on these findings, as well as on more recent work, yerba mate contains vitamins A, C, E, B1, B2, B-complex, biotin, carotene, choline, inositol, manganese, niacin, phosphorus, riboflavin, selenium, sodium, sulfur, ursolic acid, zinc, and 15 amino acids (the building blocks of protein). Additionally, since the nutrients in the tea are in liquid form, they are more readily absorbable by the body. In 1996, scientists from the University of Montreal demonstrated that extracts of I. paraguariensis inhibited LDL (low-density lipoprotein) oxidation, and in March 2000 researchers from the Universidad Nacional in Argentina found that aqueous extracts of I. paraguariensis could in fact contribute to increased antioxidants. (Antioxidants are a highly desirable group of substances that tend to neutralize the damaging oxygen free radicals attacking healthy cells in our bodies. A free radical is a molecule containing an oxygen atom that is missing an electron, which it seeks to replace by taking one from another molecule. The number of free radicals in the body is increased by such factors as radiation, poisons, cancer, and heart disease.) Vitamin E, vitamin C, and beta-carotene also have antioxidant properties and are commonly taken to supplement the body's natural antioxidant production. Unfortunately, natural production wanes with age and leaves the body increasingly vulnerable as time goes on. (See Food of the Gods for information on chocolate as an antioxidant.)
 Some typical members of the Cucurbitacae family. |
The plant's common name is formed from two words from the Quichua dialect: "Yerba" means herb, and "mate" refers to the gourd in which the tea is traditionally prepared and consumed. The gourd, Lagenaria vulgaris, is a dicot and one of about 119 genera and 775 species within the Cucurbitaceae family. Typical of this family, the plants have coiled tendrils at each node. More recognizable and economically valuable members of Cucurbitaceae are pumpkins, squashes, and melons.
The "matero," the person who prepares the tea, places a handful of dried, crushed leaves into a gourd, adding enough cold water to cover them. After a minute, the leaves are swollen from soaking up the cold water and ready for hot (but not boiling) water to be poured over them, filling the gourd. Almost immediately, the hot water takes on a characteristic brown color. The tea is consumed through a silver straw called a "bombilla," which is fitted at the base with a filter so that only clear fluid is taken up. These leaves are so packed with flavor that hot water can usually be poured over the same moistened herbs as many as ten times before they lose their color and taste.
In addition to the vitamins and minerals identified in the tea, researchers have isolated three active xanthine alkaloids: mateine, theophylline (C7H8N4O2), and theobromine (C7H8N4O2), all close relatives of caffeine. 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 drugs. Xanthines are purine bases that possess many similarities to other xanthines, including stimulation of the central nervous system. The combination of mateine, theophylline, and theobromine is credited with stress reduction and other beneficial effects of drinking the tea on a regular basis. Although these substances are related to caffeine, they have different effects inside the body. Mateine is an isomer of caffeine, and theophylline and theobromine are isomers of each other. (Isomers are chemicals that have the same number and same type of elements-in other words, the same molecular formula-but are arranged differently so that they have potentially different physical and/or chemical properties. These rearrangements of elements create a tea that acts as both a mild diuretic and a stimulant without the negative effects associated with caffeine. Thus, yerba mate is often considered a safe alternative to coffee. As the national drink in Argentina and Paraguay, yerba mate may be our next "cup of joe."
References, Websites, and Further Reading
Garcia, V., et. al. March 1997. Mineral content of Paraguayan yerba mate (Ilex paraguariensis). Arch Latinoam Nutr 47(1), pp. 77-80.
Gugliucci, A. July 16, 1996. Antioxidant effects of Ilex paraguariensis: Induction of decreased oxidability of human LDL in vivo. Biochem Biophys Res Commun 224(2), pp. 338-44.
Levetin, Estelle, and Karen McMahon. 1999. Plants and Society, 2d ed. New York: McGraw-Hill Companies, p. 269.
Simpson, B.B., and Molly C. Ogorzaly. 1995. Economic Botany: Plants in Our World, 2d ed. New York: McGraw-Hill Companies.
Troiana, S., et. al. March 16, 2000. Antioxidant effects of an aqueous extract of Ilex paraguariensis. Biochem Biophys Res Commun 269(2), pp. 357-60.
http://www.ucmp.berkeley.edu/anthophyta/asterids/aquifoliaceae.html
University of California at Berkeley's Aquifoliaceae page
http://www.colby.edu/chemistry/OChem/STEREOCHEM/
Stereochemistry on-line pages of Colby College, Waterville, Maine
Related Reading in Stern, Kingsley R. 2000. Introductory Plant Biology, 8th ed. New York: McGraw-Hill Companies.
Chapter 2: The Nature of Life
Electrons, pp. 16-17
Chapter 6: Stems
Diagram of a woody twig, node, fig. 6.1, p. 85
Chapter 7: Leaves
Leaf arrangements and types, pp. 107-8
Tendrils, pp. 114-15
Chapter 8: Flowers, Fruits and Seeds
Structure of flowers, p. 129
Monocots and dicots compared, table 8.1, p. 130
Chapter 10: Plant Metabolism
Carotene and photosynthetic pigments, p. 170
Chapter 11: Growth
Vitamins, pp. 188-89
Chapter 16: Plant Names and Classification
Development of the binomial nomenclature system, pp. 268-69
Chapter 24: Flowering Plants and Civilization
Pumpkin family (Cucurbitaceae); mate and gourds, pp. 452-53
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