The Undeveloped Potential of Medicinal Plants in the
Ozarks and Appalachians
Under one dictionary definition, any plant used for culinary, fragrance or medicinal properties is considered an herb. A friend returning from a trip to India, illustrated the plant kingdom's herbal potential. In India, he met an apprentice of an Ayurvedic physician. (Ayurveda is the traditional medicine of India, with at least a 2,000 year old history). For the apprentice's final test his teacher instructed him to go to the hills and gather plants without medicinal qualities. After several days of roaming the surrounding hills, the apprentice returned with his head hung low.
"Master," he lamented. "I was unable to fulfill the task. I found no plants without medicinal use." The teacher threw back his head in laughter and announced, "You have passed the test." (Foster 1984).
At least 20 to 25 percent of the flowering plants in any given temperate climate floristic region can be documented as medicinal plants (Duke 1986, Foster and Duke 2000). The National Academy of Sciences estimates that nearly half of the medicinal plant species documented in China have a rational scientific basis behind their use. Similar figures could be predicted for scientific vindication of medicinal plants of the U.S. (Duke 1986).
Farnsworth and Soejarto (1985) point out that Japanese scientists investigate plants growing in Japan as a source of drugs; scientists in the Soviet Union investigate their native plants; Indian scientists investigate medicinal plants of India; scientists in the People's Republic of China investigate only plants growing in China; French scientists study French plants, or species from countries formerly under French rule. However, for some strange reason, they state, American scientists rarely investigate American plants as a potential source of medicines.
A small fraction of the nearly 23,000 plants species growing wild in the U.S. have been thoroughly studied for medicinal potential. Twenty-five percent of prescription drugs sold in the U.S. include at least one ingredient directly or indirectly derived from a flowering plant. Forty major medicinal plants are involved. Of those 40 species, only 3 are indigenous to the United States (Farnsworth and Soejarto 1985). Not included in these figures is the market for crude botanicals sold to manufacturers of health and natural food products in the U.S., or the export of indigenous botanicals to European manufacturers.
By the end of the 20th century at least 10 percent of all flowering plants were projected to become extinct. As many as 75 percent of the estimated 500,000 flowering plant species are indigenous to moist tropical forests. The situation has generated little concern in most sectors of society outside the conservation movement. (Principe 1989).
While very few of these plant species have been investigated for therapeutic potential, the consequence of loss of new drugs for the treatment of cancer, AIDS, or other disease is often used as a rallying cry for the need for protection or for funding for protection of threatened or endangered species. Unfortunately, virtually none of the 3,000+ endangered or threatened flowering plant species of the United States have been studied for their potential economic value as drug plants.
This regrettable situation in the United States largely results from the general lack of interdisciplinary research in the diverse specialties of biological, medical, and chemical sciences necessary for evaluation of potential medicinal use.
The flora of the Ozarks includes roughly 2,00 species of vascular in over 150 plant families. It is safe to assume that at least 500 species of the region can be documented as medicinal plants. At least 35 species of medicinal plants native to the region are currently sold in tonnage on domestic and international botanical markets. Many of these species are extractively harvested from the eastern deciduous forest, especially in the Appalachians and Ozarks.
This incomplete listing includes:
Wild medicinal plants from the region can be placed in two broad categories: 1) indigenous species; 2) naturalized species, including introduced and adventive plants. In most cases introduced species are undesirable elements of the flora. One way to control them might be to find a way to use them for economic gain, including medicinal purposes (Foster 1989a, 1990).
The Japanese Honeysuckle Lonicera japonica is one example. The dried flowers (Jin-yin-hua), and the dried stems with leaves attached (Ren-dong-ten), are both official drugs of the 1985 edition of the Pharmacopeia of the People's Republic of China. The medicinal use of the flowers is mentioned in early Chinese herbals including Lu Chan Yan Ben Cao ("Materia Medica from steep Mountainsides" author and date unknown) and Ming Yi Bie Lu, attributed to Tao Hong-Jing (500 A.D.). The use of the stems is first mentioned in Ben Cao Jing Ji Zhu, attributed to Tao Hong-Jing, published around the year 500 A.D.
Pharmacological research has shown that flower extracts have a strong antibacterial effect against Salmonella tyhpi, Pseudomonas aeruginosa, Staphyloccocus aureus, Staphyloccocus pneumoniae, and Mycrobacterium tuberculosis. In vitro studies have indicated antiviral activity. Rat studies suggest that Honeysuckle flower preparations may have a serum cholesterol lowering effect. Components of the flowers have experimental antispasmodic, diuretic, and stomachic effects. Preparations of the flowers have been shown to promote leukocytic phagocytosis and phagocytic activity of inflammatory cells, suggesting immune enhancement activity. Clinical studies published in the past 20 years in China have reported on the use of various preparations of the plant (from teas to injectable drugs) in the treatment of infectious hepatitis, strept throat, pneumonia, acute bacillus dysentery, cervical cancer, acute eye inflammations, urticaria, diarrhea in children, hyperlipidemia, and leptospirosis (Foster and Yue, 1982, Chang and But 1987).
Non-native species naturalized in the Southern Appalachians of current
economic importance in American botanical markets, some of which are extractively
harvested from the region, include:
Over 1600 medicinal botanical commodities are commonly traded in the United States. Medicinal herbs are sold in several market segments, including crude drugs for the manufacture of pharmaceuticals, health-care products sold in the natural and health food market, ethnic markets, and export markets.
Traditionally, many American medicinal plants have been gathered from the wild instead of being cultivated. Most of the indigenous North American medicinal plants currently sold on world markets are extractively harvested in relatively large quantities from native ecosystems. In reviewing a commercial bulk herb catalog recently, I noted 56 species of indigenous plants listed that are sold in tonnage on domestic and export markets. Of those 56 species, only seven species are supplied in appreciable quantities with cultivated material. Given the increased interest in medicinal herbs, currently with a 10 percent annual growth rate in domestic markets, the extractive harvest of wild medicinal plants cannot be sustained over the long term.
A number of nursery firms have discontinued sale of native plant material, unless those plants are nursery propagated and cultivated, rather than harvested from the wild. "Nursery-propagated" is the key phrase. Some plant dealers are simply placing wild-harvested live plants in cultivated plots for a year, then selling the plants as cultivated.
Lady's Slippers (Cypripedium spp.) may suffer from this situation. In 1989. the International Herb Growers and Marketer's Association and the American Herbal Products Association passed resolutions encouraging members not to sell wild-harvested Lady's Slipper roots, based on the threatened nature of wild orchids. Unfortunately, there are reports of people taking wild-dug Lady's Slipper plants, placing them in cultivated beds for a year, then selling the dried root as cultivated material.
International commerce of orchids and other plants and animals deemed threatened or endangered is regulated by the Fish and Wildlife Service, under the guidelines of CITES (Convention of International Trade in Endangered Species). Lady's Slipper orchids are also subject to the provisions of the Lacey Act, a law regulating interstate commerce of threatened and endangered species, if those species are protected by laws in one or more states.
Many conservation organizations and agencies have taken action on or expressed concern on the sale of wild-harvested nursery material. These groups include The New England Wild Flower Society, The National Wildflower Research Association, Nature Conservancy, the Natural Resources Defense Council, the Eastern Native Plant Alliance, and United Plant Savers. These organization and others advocate the conservation of native plants and their habitats, and strongly discourage the the extractive harvest, sale, and purchase of wild-harvested native plant materials for commercial purposes.
All of these factors are pointing to the need for botanical sellers and buyers to begin to take a second look at the long-term viability of sourcing native botanicals traditionally harvested from the wild. Those interested in supplying domestic and export markets should take a serious look at developing cultivated sourcing rather than wild-harvested native plants.
The potential grower, however is faced with a veritable dearth of information on the cultivation of medicinal plants. Ever ask an extension agent to supply all available information on the cultivation of goldenseal? Basic research on the germplasm, demographics, general biology, propagation, cultivation, harvest, and handling of medicinal plants is needed before commercial cultivation can be developed on an appreciable scale.
In addition to further developing medicinal plant commodities already traded on world markets, there are numerous opportunities for researching plant species of the southern Appalachians related to existing medicinal plant groups. For example, Osha root (Ligusticum porteri), was one of the most important medicinal plants used by indigenous groups of the Western U.S., especially for viral and bacterial infections. A Chinese species, Ligusticum wallichi, is used for parallel purposes to the Western North American Osha. Perhaps Ligusticum canadense, a widespread species in the southern Appalachians could be researched for potential similarities with the two economically significant species mentioned above.
Echinacea laevigata, a Federally-listed endangered Appalachian species, might be further protected, propagated, cultivated and perhaps economically developed if appropriate research revealed similar medicinal potential with its close relative, Echinacea purpurea. Over 350 products are available in Europe containing Echinacea purpurea, well-known in Germany as a non-specific stimulant to the immune system. Phytochemical research could also once and for all lay to rest questions relative to E. laevigata's taxonomic position (Foster 1985, Bauer and Foster 1989).
An aspect of ethnobotany receiving recent attention is the evaluation of herbal medicine by comparing the similarity of plant use by various and different groups in widely separated parts of the world (Croom 1983). Parallel plant uses of independent origin suggests the inference of a rational scientific basis for use.
In relation to parallel plant uses in a historical or modern context in eastern Asia and eastern North America, there are special phytogeographical circumstances providing opportunities to explore medicinal plant development by comparative ethnobotanical, morphological, and phytochemical data. Biogeographic factors enhancing these opportunities include:
The disjunct genera between the eastern portions of North America and Asia include many genera of historically important medicinal plants used as folk medicines or drugs in both regions, such as the woody genera Catalpa, Gelsemium, Hamamelis, Illicium, Lindera, Liriodendron, Magnolia, Menispermum, and Sassafras; plus the herbaceous genera Caulophyllum, Diphylleia, Jeffersonia, Panax, Penthorum, Podophyllum, Saururus, Stylophorum, and Triosteum. In addition, there are closely related genus pairs, now separated taxa, that at one time contained species placed in the same genus. Conspicuous medicinal plants in this category include the monotypic eastern North American Hydrastis canadensis L. and the monotypic Japanese endemic Glaucidium palmatum Sieb. & Zucc. (Foster 1986, 1989b).
The existence of species pairs in eastern North American and eastern Asia from wide-ranging genera presents further possibilities for exploring parallels in ethnobotanical data. In the Umbelliferae, the genus Osmorhiza has approximately eleven species widely distributed in Asia and North America, to southern South America. The eastern North America O. longistylis, and O. claytoni are closely related to the eastern Asian O. aristata. Both the North American species as well as O. arisata var. laxa are used as folk medicines in their respective natural ranges (Foster 1986, 1989b).
In summary, at least 50 species occurring in the Ozarks are already traded on commercial botanical markets. Most are extractively wild-harvested rather than cultivated, with little attention to sustainable management. More than 450 other medicinal species can be conservatively predicted from the flora of the region. Numerous opportunities exist for using comparative ethnobotany as a starting point for scientific evaluation of the medicinal potential of numerous plant species. Well-coordinated, multidisciplinary research efforts, coupled with germplasm conservation, are necessary for successful and sustainable economic development.
Cited or Useful References
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