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The Undeveloped Potential of Medicinal Plants in the
Ozarks and Appalachians
A discussion paper
by Steven Foster
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:
Black Cohosh, Cimicifuga racemosa, Ranunculaceae
Black Walnut (bark and leaf) Juglans nigra, Juglandaceae
Bloodroot Sanguinaria canadensis, Papaveraceae
Blue Cohosh Caulophyllum thalictroides, Berberidaceae
Boneset Eupatorium perfoliatum, Compositae
Canada Snake Root Asarum canadense, Aristolochiaceae
Cedar, Red Juniperus virginiana, Cupressaceae
Cranesbill (root) Geranium maculatum, Geraniaceae
Elder Flowers Sambucus canadensis, Caprifoliaceae
Evening Primrose Oenothera biennis, Onagraceae
Germander, Am. Teucrium canadense, Labiatae
Ginseng, Am. Panax quinquefolius, Araliaceae
Goldenseal Hydrastis canadensis, Ranunculaceae
Hydrangea (root) Hydrangea arborescens, Hydrangeaceae
Lobelia Lobelia inflata, Campanulaceae
Maidenhair Fern Adiantum pedatum, Adiantaceae
Mayapple Podophyllum peltatum, Berberidaceae
Passion Flower Passiflora incarnata, Passifloraceae
Pennyroyal, American Hedeoma pulegioides, Labiatae
Pipsissewa Chimaphila umbellata, Ericaceae
Prickly Ash (bark and berries) Zanthoxylum clava-herculis, Zanthoxylum
americanum, Rutaceae
Sassafras Sassafras albidum Lauraceae
Scullcap Scutellaria lateriflora Labiatae
Shavegrass Equisetum hyemale Equisetaceae
Slippery Elm (bark) Ulmus rubra Ulmaceae
Solomon's Seal (root) Polygonatum biflorum Liliaceae
Squawvine Mitchella repens Rubiaceae
Stone Root Collinsonia canadensis Labiatae
Sumac Berries Rhus glabra Anacardiaceae
Virginia Snakeroot Aristolochia serpentaria Aristolochiaceae
White Oak Bark Quercus alba Fagaceae
Wild Lettuce Leaf Lactuca spp. Compositae
Wild Yam Root Dioscorea villosa Dioscoreaceae
Witch Hazel Hamamelis virginiana Hamamelidaceae
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:
Annual Wormwood Artemisia annua Compositae
Blackberry Leaf Rubus spp. Rosaceae
Burdock (root, leaves & seeds) Arctium lappa Compositae
Catnip Nepeta cataria Labiatae
Chickweed Stellaria media Caryophyllaceae
Chicory Root Cichorium intybus Compositae
Cleavers Galium aparine Rubiaceae
Colts Foot Leaf Tussilago farfara Compositae
Dandelion (leaf & root) Taraxacum officinale Compositae
Dog Grass Agropyron repens Graminae
Elecampane Root Inula helenium Compositae
Heal All Prunella vulgaris Labiatae
Japanese Honeysuckle Lonicera japonica Caprifoliaceae
Horehound Marrubium vulgare Labiatae
Horseradish Armoracia rusticana Cruciferae
Malva leaf Malva rotundifolia Malvaceae
Motherwort Leonurus cardiaca Labiatae
Mugwort Artemisia vulgaris Compositae
Mulberry Leaf Morus alba Moraceae
Nettle Urtica dioica Urticaceae
Oat Straw Avena sativa Graminae
Plantain Leaf Plantago major Plantaginaceae
Raspberry leaf Rubus idaeus Rosaceae
Red Clover Flowers Trifolium pratense Leguminosae
St. Johns Wort Hypericum perforatum Hypericaceae
Shepherd's Purse Capsella bursa pastoris Cruciferae
Tansy Tanacetum vulgare Compositae
Valerian root Valeriana officinalis Valerianaceae
Yarrow Achillea millefolium Compositae
Yellow Dock Rumex crispus Polygonaceae
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 classic series of plant disjunctions between the eastern portion
of the two continents, but including some genera in western North America;
- The existence of many species pairs from wide-ranging genera found
in eastern Asia and North America, as well as other continents;
- Circumboreal species utilized by indigenous peoples of North America,
Asia and Europe.
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.
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