Medicinal Wildflowers and Their Conservation
Dr. James A. Duke, former chief medicinal plant expert at the United States Department of Agriculture created a database documenting over 80,000 plant species used as folk medicines worldwide thats about one-third of flowering plant species. The WHO estimates that herbal medicines in global trade are represented by 21,000 plant species, primarily collected in regions with low wages such as such as South America, Africa, and Asia. Between 70 and 90 percent of medicinal plants are harvested from natural habitats, with only between 50-100 species supplied by significant cultivated source material. As many as 140 species of native North American plants enter the commercial herb trade at least on a small scale. Some like purple coneflower (Echinacea species), black cohosh (Cimicifuga racemosa), American ginseng (Panax quinquefolius), and saw palmetto berries (Serenoa repens) are harvested in significant tonnage.
Medicinal Plants in the Modern World, From Prescription Drugs to Dietary Supplements
Plants still play a crucial role in modern Western medicine. According to medicinal plant researcher Dr. Norman Farnsworth of the University of Illinois in Chicago, approximately 25 percent of prescription drugs contain at least one plant-derived compound, or are based on plant-derived chemical models. That percentage has remained relatively stable (plus or minus 1 percent) since 1959. On a worldwide basis, 119 distinct chemical substances, derived from ninety-one plant species are used in prescription drugs;. The list includes well-known drugs such as derivatives of the common foxglove (Digitalis purpurea) , used in the management of heart problems. Anti-cancer drugs used in chemotherapy include compounds from the common ornamental Madagascar periwinkle (Catharanthus roseus) used for Hodgkins disease and various forms of leukemia. Chemicals derived from the common mayapple (Podophyllum peltatum) are used in small cell lung cancer and testicular cancer. Paclitaxel (better known by its trade name Taxol) derived from various species of yews (Taxus species) has given women with certain forms of breast cancer or ovarian cancers new treatment options. Herbal medicine is not a throwback to the dark ages.
In Germany, herbal medicines called phytomedicines are dispensed by pharmacists and prescribed by physicians. They are sold as drugs, many available over-the-counter, and include familiar American wildflowers such as black cohosh (Cimicifuga racemosa) and purple coneflowers (Echinacea species). Over 300 herbal medicines are approved as drugs in Germany.
Many phytomedicine products from the German market are sold as "dietary supplements" in the United States. The Dietary Supplement Health and Education Act of 1994 attempted to create a federal framework for the regulation of dietary supplements. Herbs were for the first time were allowed to carry health claims. The net effect of the 1994 legislation was to open the flood gates of the herb market. In 1992, the market for herb products used for health purposes had estimated sales at the retail level of about $500 million, with products sales primarily limited to health and natural food stores.
According to Mark Blumenthal, Executive Director of the American Botanical Council in Austin, Texas, a non-profit information clearinghouse for scientific information on herbs and medicinal plants, noted, "as the fastest-growing segment of the dietary supplement industry, herbs were no longer the domain of health-food stores, mail-order houses, and multilevel marketers. They became big business in places where big business is donedrugstores, supermarkets, and mass merchandisers. Herb sales reached $2 billion in 1996."
Sales continued to climb until the market reached a peak in 1999, with an estimated $3.2 billion in consumer sales. However, the market was flooded with cheap, low-priced and often low quality products. Hyperbolic claims confused consumers. Consumer confidence plummeted. Sales slowed dramatically in mass market channels. A perception arose that the products were unregulated (though long-awaited guidelines for good manufacturing practices have been issued by the FDA in March of 2003). Concerns over safety, such as possible interaction with prescription drugs, or health problems and even widely publicized fatalities for inappropriate weight-loss or "legal high" formulations containing Ephedra (also known as ma-huang), have impacted the market.
In the various tides of ebb and flow in the market have come increased demand for wild harvested raw materials. Along with the demand, came conservations concerns over the harvest of wild medicinal plants such as goldenseal (Hydrastis canadensis), Echinacea (Echinacea species), and Black cohosh (Cimicifuga racemosa, also known as Actaea racemosa) in the dietary supplement market. In addition, the problems in sourcing enough of the compound paclitaxel from the Pacific Yew (Taxus brevifolia) highlight problems of sourcing and conservation issues in new palnt-based prescription drug development.
Yew and Taxol Problems and Solutions to New Drug Development
Paclitaxel (better known by its trade name taxol) is a drug used in chemotherapy for the treatment of certain forms of breast and ovarian cancer. It was discovered by researchers at the National Cancer Institute's (NCI) general plant screening program undertaken from 1958 to 1980 in which over 35,000 plant species were evaluated for anticancer activity/ In January of 1993, paclitaxel was approved in the U.S. as a therapeutic agent for certain forms of ovarian cancer, and the following year, approved for the treatment of some breast cancers.
The bark of the North American Pacific Yew (Taxus brevifolia), a small understory tree in the Pacific Northwest, served as the first source of the drug. In response to the success of early clinical trails, demand rose to 60,000 pounds in 1987-1988. However, thirty pounds of dried Pacific Yew bark yield only one gram of paclitaxel. This raised concerns about the future supply of the bark, and its impact on the survival of the tree species. In 1990 the Fish and Wildlife Service, responsible for implementation of the endangered species act, rejected a petition to classify Pacific Yew as a threatened species. Satellite imagery and ground surveys resulted in an estimate of 130 million trees in over 1,700,000 acres of public lands in Washington and Oregon.
Clinical trials were slow to develop in the late 1980s due to supply problems of sourcing paclitaxel from Taxus brevifolia. A break-through by French scientists showed that a related compound, derived from the needles of the common ornamental English yew (T. baccata) could be transformed into taxol, thus providing a sustainable source of supply without killing the plant. Therefore the bark of Pacific yew no longer was needed as a source of the drug. As a result of its experience, with the Pacific Yew sourcing problems the NCI has developed a strategy to initiate exploratory research programs for large scale-up production of raw materials early on following proof of confirmed antitumor activity.
Echinacea A Case of Mistaken Identity
Echinacea or purple coneflowers were used for more medicinal purposes than any other plant by native groups of the Prairies. Introduced into pharmacy in the 1890s, up to the 1920s, Echinacea preparations were the most widely prescribed native medicinal plant by physicians in the United States. Prior to the development of antibiotics, Echinacea was used to help fight infections. In the 1930s, Echinacea products were sold on the Germany market. Now over 380 Echinacea products are sold in Germany alone, where some Echinacea species are approved for the prevention and treatment of upper respiratory tract infections, and in topical products for hard to heal wounds and sores.
The genus Echinacea is found exclusively in North America, and is represented by nine species, three of which Echinacea angustifolia, E. pallida, and E. purpurea are traded commercially. The entire world supply E. purpurea is commercially cultivated so it does not represent a conservation concern. The vast majority of Echinacea angustifolia and E. pallida supplies are harvested from wild habitats in the Midwest and plains states. Its growing popularity has placed increased pressures on wild populations, resulting in attention to its sustainable harvest.
On wholesale herb markets wild-harvested Echinacea angustifolia is sold as "Kansas Snakeroot." Unfortunately "Kansas Snakeroot" is not always just E. angustifolia, but has been indiscriminately mixed with E. pallida . The problem does not end there. Additional Echinacea species including the Ozark endemics Echinacea paradoxa (yellow coneflower) and Echinacea simulata also enter mixed lots of Kansas Snakeroot, along with Echinacea atrorubens, which occurs in a narrow range in Texas, Oklahoma and Kansas. Two rare species of Echinacea have been afforded protection under Federal law. The Tennessee coneflower Echinacea tennesseensis, known from only six populations in Tennessee, was one of the first plants to be placed on the Federal Endangered Species List. In 1992, a rare species from the Appalachians of Virginia, the Carolinas, and Georgia, the smooth-leaved coneflower Echinacea laevigata, was also added to the Federal endangered species.
Black cohosh Increasing Demand by Aging Baby Boomers
Preparations of black cohosh (Cimicifuga racemosa, recently reclassified as Actaea racemosa) have been used for over 50 in Germany for the treatment of symptoms related to menopause. At least a dozen controlled clinical studies confirm safety and effectiveness of the root extracts. A recent assessment of the herbal trade by TRAFFIC USA, a monitoring of the World Wild Life Fund, has suggested that black cohosh be reviewed for possible includsion in CITES appendix II. According to a summary of the conservation status of black cohosh and related species, Julie Lyke, formerly of the U.S. Fish & Wildlife Service Division of Scientific Authority, black cohosh was one of the fastest growing herbal products, with demand increasing 477 percent n 1999 over 1998. 1998 sales increased by 511 percent over 1997 sales. Black cohosh is found in rich woods of the eastern deciduous forest. The American Herbal Products Association estimated that over 1.1 million pounds of dried black cohosh were harvested in 1997-1999. Attempts to develop quantitative data to support its listing in CITES may be moot, as successful large-scaled cultivation of the root has been developed by a German pharmaceutical company that makes the best-selling black cohosh product. Still efforts may be undertaken to limit the export of wild-harvested roots from the United States.
The Case of Goldenseal
Perhaps more than any other herb in the last ten years, goldenseal has received attention in conservation circles. Most goldenseal is wild-harvested. Demand increased by word-of-mouth claims that goldenseal preparations could be taken to mask the results of tests for illicit drugs in urinalysis. Now, however, many drug testing labs are also testing for the presence of compounds unique to goldenseal in urinalysis, in order to identify potential drug users. Prior to this use, goldenseal was perceived as a natural antibiotic by health food consumers.
WWFs TRAFFIC North America formally petitioned the United States Fish and Wildlife Service in 1997 to propose goldenseal under the provisions of the CITES treaty as an "Appendix II" listing, after finding that over 20,000 lbs of goldenseal were exported between 1990 and June, 1996. The petition was passed which meant from September 18, 1997 on, goldenseal exports are regulated under the CITES treaty.
Demand for goldenseal on the domestic market has declined, the price has declined, and consequently goldenseal is not under the harvest pressure that it experienced just five years ago. The future of goldenseal is still tenuous. When the price of goldenseal went up four or five years ago, many growers began establishing plantings of goldenseal. But with the downturn in price, these same growers are beginning to abandon these cultivation efforts.
In the United States attention has been drawn to the issue of medicinal plant conservation by several grass-roots organizations such as United Plant Savers (UpS) based in Meigs County, Ohio. The problem has also come to the attention of the U.S. Fish and Wildlife Service, National Park Service, U.S. Forest Service and other government agencies which control natural resources and their utilization. In addition, non-government organizations such as TRAFFIC North America, the wildlife trade monitoring arm of the World Wildlife Fund have tackled the problem. Some states, such as North Dakota and Montana have instituted legislation to control the harvest of wild Echinacea on both private and public lands.
Writing on goldenseal in a 1904 issue of Journal of the American Pharmaceutical Association, pharmacist John Uri Lloyd offered this prophetic wisdom, "Let me say in closing, that the exorbitant price now demanded for Hydrastis [goldenseal] is altogether owing to ordinary mans improvident disposition and destructive vandalism. The present scarcity is unnecessary, but promises to be cruelly lasting, there being seemingly little prospect of cultivated Hydrastis drifting into market in the very near future, in quantity sufficient to bring the price to a normal condition.. . . In this connection, I again plead for government and state intervention in such directions as this. If it is proper to preserve a lingering group of bison, or to search the land over for our vanished wild pigeon, why is it not proper to conserve, with the help of the strong hand of authority, Americas valued flora from absolute extermination?"
John Uri Lloyds nearly century-old question still awaits an answer.
The Role of CITES
When it comes to the importation and exportation of plants or animals with conservation concerns, the United States is a signatory of a treaty called CITES (Convention for International Trade in Endangered Flora and Fauna). With over 165 nations signed on, CITES is the treaty that regulates or bans trade in high-profile animal-derived goods such as elephant ivory. Species not allowed in international trade (such as Elephant ivory) are placed in CITES Appendix I. It also takes action on less visible items such as medicinal plants.
Plants or plant parts listed in CITES Appendix II are controlled and monitored in trade, "in order to avoid utilization incompatible with their survival." Basically, this means that at the country of exportation, a trail of permits is created to help authorities monitor the status of the species and how much is being traded. In the United States, the Fish and Wildlife Service has jurisdiction over CITES, with cooperation from USDA and state agencies. The international trade of American ginseng (Panax quinquefolius) and Goldenseal are regulated under the provisions of CITES Appendix II as are a number of other medicinal plant species including Indian Snake Root Rauwolfia serpentina and the Himalayan Mayapple Podophyllum hexandrum, both from India. In the United States, the Fish and Wildlife Service has jurisdiction over CITES, and conservation groups such as the World Wildlife Funds TRAFFIC North America office closely work with the agency to monitor progress.
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