|Medicinal Plants: Rescuing a Global Heritage (WB, 1997, 80 p.)|
|1. The global background|
As was noted in the previous volume, plants are still an indispensable source of medicinal preparations, both preventative and curative. Despite immense progress in synthetic chemistry and biotechnology, hundreds of species are recognized as having therapeutic value. Many of those are commonly used to treat and prevent specific ailments and diseases.
While health providers in industrialized nations have reduced their dependence on the Plant Kingdom, the majority of developing nations still rely on herbal remedies. Medicinal plants constitute one of the important overlooked areas of international development. They represent a form of biodiversity with the potential to do much good, and not just in the field of healthcare. Indeed, the production and processing of medicinal plants offers the possibility of fundamentally upgrading the lives and well-being of peoples in rural regions. It can also help the environment and the protection of habitats and biodiversity of the developing world.
The potential world market of phytomedicines or herbal medicines is very large, but its significance to the global economy can at this point only be inferred from a few sources of diverse and inadequate data. The World Health Organization estimated in 1980, for instance, that the world trade amounted to $500 million a year. However, information from diverse sources suggest that the overall trade in botanicals has since then greatly increased. This has been accelerated by a renewed interest in traditional medicines in many developing countries and especially in Europe and North America.
The developing countries, particularly those in Asia, are the main suppliers to the developed countries of plants used in pharmacy. However, in Africa and Latin America local and regional trade in medicinal plants is growing rapidly along with an increasing demand by international plant traders hoping to discover new "wonder" drugs.
Germany is one of the largest importers of medicinal plants. The Convention on International Trade in Endangered Species (CITES) has determined that Germany's imports include at least 40 threatened or endangered species. Many were originally listed in CITES to protect them from heavy exploitation for the ornamental trade. However, it became apparent that many of these were also used for medicinal purposes.
There is a reason for Germany's imports of medicinals. Of all the western nations, Germany has made the greatest progress in bridging the gap between traditional and Western medicines. Every medical student there is taught about phytomedicines and more than 80 percent of all German physicians regularly use herbal products. The government requires that plant drugs must be standardized and of proven safety and efficacy. Safety of long-used natural products is generally assumed, if no side effects have been reported. Clinical experience noted by physicians, scientific evidence published in technical journals, and data supplied by manufacturers are the basis for the doctrine of "reasonable certainty," which Germans accept as a substitute for strict clinical trials. The German experience is being closely watched by both industrialized and developing countries as it offers an example of how to integrate the two systems.
The global demand for medicinal plants is expressed from four identifiable sources: (i) pharmaceutical industries, (ii) traditional healthcare systems; (iii) individual traditional health practitioners, and (iv) women in family home care. The money values involved depend not only on the extent to which barter or non-monetary exchange is a factor, but also the degree to which the production and sale are concentrated in visible locations, regulated and taxed.
Gauging the extent and growth of the global trade in herbal ingredients is made difficult by unpredictable fluctuations in price. Such fluctuations - typically over six to nine year periods - are common as the availability of many wild medicinal plants goes from oversupply to scarcity very quickly and then slowly stabilizes again. Variations in price due to supply conditions make it difficult to determine the extent to which demand is increasing. Government(s) and the local private sector would probably be more willing to fund research on the extent of existing and potential supply of medicinal plants if they had a better idea of the potential (and existing) market. From that they could tell how much could be sold, at what price, and therefore what profit was to be made.
The regulated trade provides all the present data on the market value of medicinal plantsfrom raw material to finished product. The unregulated market includes all manner of medicinal plants where there is no market accounting (largely because the government draws no benefit from these sales). This informal use of medicinals includes home use, exchange between neighboring families, collecting and sale in rural markets, use by traditional health practitioners and other undocumented transactions.
The most complete data are, unsurprisingly, available from the official Chinese and Indian healthcare systems, but even that is incomplete. Even where there are local pharmaceutical industries, the figures on general herbal drug sales to the public are often unavailable. Assessing informal medicinal product sales by traditional health practitioners and vendors, primarily peddled by women in local markets, would be very difficult due to a lack of records. Similarly, products grown in home gardens and administered to family members have an unknown value. It is this cultural value, that is rarely, if ever, captured in economic analysis. Yet it is likely to represent a significant portion of the total economic benefit provided by these plants.
A number of Asian countries (including China, India, both Koreas, Thailand, Indonesia and the Philippines) have the technical background, knowledge, and existing pharmaceutical industries to process raw materials and market finished products. However, the majority of developing countries in Latin America and Africa lack the industrial base and financial resources to expand this market rapidly. As a result, 86 percent of finished health products are still manufactured in Europe and North America. 6 In virtually every developing country, local healthcare needs are satisfied primarily using raw materials from plants. The majority of people just cannot afford to purchase imported pharmaceutical products.
Not much has been done to assist developing countries to develop their medicinal-plant resources. However, two organizations - the International Organization of Chemical Sciences in Development (IOCD), Falls Church, Virginia, USA, and Biotics Ltd., University of Sussex, UK - have taken an active role in this. IOCD has helped establish the Network for Analytical and Bioassay Services in Africa (NABSA), which links cooperating laboratories with capabilities to provide services in chemical spectroscopy and biological evaluation. Services currently offered by NABSA Centers are in Ethiopia (Addis Ababa), Kenya (Nairobi), Madagascar (Antananarivo), and Botswana (Gaborone). Biotics Ltd. provides access to high technology screening through training of phytochemists. As a result, a number of independently-owned companies have been created in developing countries to prepare plant extracts.
Developing countries are entering a new era when community health services will likely occupy an evermore prominent position in national priorities. The type of production, processing, and manufacturing of a large array of medicinal plants produced in the rural sector - and in turn the ability of developing countries to invest in medicinal plant (phytopharmaceutical) industries - will determine the future quality of those community health services.
To derive optimal benefit from the conservation and cultivation of its medicinal-plant genetic resources, each country must develop an integrated strategy for their management and use, identify policies, and enact legislation that will encourage a broadly-based delivery of the benefits to be realized from these actions rather than allowing the majority of the economic benefits to accrue to a smaller but well-place minority.
So far, however, few developing countries are doing this. In order to stimulate more such action, three regional workshops sponsored by Global Initiatives for Traditional Systems of Health (GIFTS) were held in Latin America, Africa and Asia in 1994-95 followed by an international meeting in England in late 1995. All stressed the need for clearly-defined policies promoting the safe utilization of traditional medicine. Recommendations included:
- the documentation and promotion of traditional medicines with proven efficacy;
- increased funding of research and development programs;
- need to evolve policies which involve local communities in conservation programs;
- document and cultivate endangered plant species known to have medicinal uses;
- recognizing the role of women;
- information exchange; and education at all levels to increase awareness of medicinal plants and their economic potential in drug production.
All countries where medicinal plants and traditional medicines are used are aware of the need for regulating the use of medicinal substances. Indeed, most developing countries have a heritage in the use of plant-based medicine that is far older than the modem of medicine. China probably has the strictest criteria for regulating the sale of traditional plant-based medicines. Chinese authorities are well aware of the problems and constraints facing them in the production, processing, and marketing of herbal medicines. The Government of India, while constantly upgrading its controls, does not exercise any regulatory control over the use of "home-made" remedies that are used by a large segment of the vast Indian population.
The European Scientific Cooperative for Phytotherapy (ESCOP) is currently drafting fifty monographs of product characteristics to be used as a basis for licensing phytotherapeutics in all member states of the European Union (EU). Since January 1995, a decentralized marketing authorization procedure has existed in addition to the national licensing of individual member states. Following enactment in 1994 by the United States Government of the Dietary Supplement and Health Education Act (DSHEA) greater effort has been made to develop guidelines for quality control, good management practice, and to provide a sound scientific basis for ensuring proper identity and purity of finished products. Such activities by the industrialized countries put greater pressure on the developing countries to regulate trade in medicinal plant raw materials.
Sociocultural factors play an important role in the preservation of medicinal plants and the people's continued reliance on traditional medicine. Often, villagers will use a modem medicine to relieve their immediate symptoms, while turning to traditional medicine for treating the root cause of the illness. Revival of traditional health systems following decolonization, as well as increased self-determination of indigenous groups, has led an increasing number of developing country governments to re-evaluate and promote their traditional medicine systems. Such systems are a response to the conditions and needs of local populations. To have any chance of success, however, new public health systems must necessarily incorporate the cultural habits handed down through generations.
Traditional Knowledge. Most developing country societies view traditional medicine practices as an integral part of social culture. During colonial times, however, traditional healthcare systems gradually lost patronage and favor especially with the urban populationsdue notably to the imposition of Western culture and to the support given to Western (allopathic) medicine. Since the demise of colonialism, there has been a gradual reestablishment of the traditional systems of teaching and dispensary in indigenous medicine. It is in light of this resurgence, both locally and internationally, that pressure is being placed on an important component of that healthcare--the plants.
In some cases, however, traditional practitioners have resisted attempts to document their knowledge. They see such disclosures as being detrimental to their practice. In addition, they treat with skepticism the outsiders' interest in their plants and therapies, rightly believing they will receive no credit or royalties for any future drug discoveries derived from their knowledge.
Yet exchanging experiences and scientific data on various aspects of traditional medicine prevalent in different parts of the world is an important step in helping save the plants and the knowledge of their use. And there are also greater advantages to be reaped. In many parts of the world, for instance, there are no doctors and no Western drugs. Even where doctors are available, import restrictions and government budgeting often mean there are insufficient medicines to distribute. Sometimes, preparations are used even though they have passed their expiration date.
In such circumstances, it would probably be better to use herbal medicines-all of course chosen with care, supplied with a maximum of quality assurance, and prescribed by practitioners the patients trust.
Taken all round, the availability of locally-grown drugs, their relatively low cost, and the minimal side-effects associated with many of the drugs are important factors in providing primary healthcare. For persons who have never experienced sickness or illness without medicines, these are important considerations.
Women's Role. In many of the developing countries women serve as conservators and cultivators of medicinal plants. Through their household practices they use traditional approaches in caring for the health needs of the family. In Africa and Latin America, women constitute the majority of traditional medical practitioners, as well as the primary gatherers of medicinal plants. Women are the traditional birth attendants, delivering and tending the mother's pre- and post-natal needs.
Although often unappreciated, most mothers are the de facto healers of the family tending to accidents and ailments with medicinal-plant remedies cultivated in their home gardens, maintaining the family diet, administering medicines, providing counseling and essential emotional support. It would not be an exaggeration to suggest that virtually every leader of a developing country benefited at some time in his/her formative years from the medicinal-plant knowledge of a mother or grandmother.
Enhancing Social Capital. The importance of traditional medicinal-plant knowledge or social capital is evident by the need for "bioprospectors" (Western specialists seeking new and profitable drugs from nature) to recruit indigenous peoples to identify local flora and describe their uses and healing properties. The need to protect intellectual property rights (IPR) has now become a major issue both for developing countries whose genetic resources are being exploited, and for developed countries whose patent law cannot always be enforced in developing countries.
Legal restrictions over access to, and removal of, medicinal-plant germplasm. are easier to enforce than legal protection over the use of the information represented by that genetic material (intellectual property rights). In the past, many countries have failed to adequately enforce such property rights, partly because of a lack of awareness of the potential value contained within their genetic resources. The recognition of IPRs, however, may provide a very important incentive to many countries to institute environmental policies preserving biodiversity. 9 A careful balance needs to be achieved between restricting access to plants, which may enable economic returns to be achieved, and restricting access to information which may have opportunity costs.
Generating Income. Medicinal plants are both a source of income and a source of affordable healthcare. As described above, many poor people derive their only income from harvesting medicinal plants. This income however, is probably declining in those countries where natural habitats are disappearing. A strategy that integrates conservation and cultivation of medicinal plants could create long-term employment and income opportimities. Agricultural R&D, and production will require qualified professional and technical workers, and labors, many of the latter can be recruited locally. Expanded local pharmaceutical industries would also require additional workers at all levels.
If existing medicinal-plant resources are to continue to meet demand now and in the future, they will need to be adequately protected through the development of appropriate policies and legislation. Awareness of the conservation issues and of the importance of sustainable utilization needs to be raised among all stakeholders. Perhaps most importantly, local people need to be supported and encouraged to take the necessary steps to protect this valuable resource. The collection of medicinal plants must be guided by an accurate knowledge of the biology of the species concerned, and steps must be taken to avoid over-exploitation, and the collection of rare or otherwise endangered species.
Preserving Wild Genes. Fortunately, many plant species consist of thousands of populations. These together form a gene pool in which a more or less free gene exchange can take place. This is a feature that can be utilized by plant breeders to protect medicinalplant diversity.
Box 1: The Lost Ancient Plant We Could Use Today
As an example of the importance of preserving medicinal plants consider the case of silphion, a weed once used as a contraceptive. It was apparently so effective that the Ancient Greeks literally revered it. Now, with population growth seemingly out of control a plant like this could have immense significance. Unfortunately, the Greeks used so much of it, it became extinct. Botanists can no longer find the species.
Between 570 and 250 BC the majority of coins minted in ancient Cyrene, a city situated in what is now the eastern part of Libya, carried the embossed picture of the Silphion plant. This reflects the enormous economic importance this plant had for the city over four centuries.
The perennial roots and strongly ribbed annual stems of the Silphion plant were eaten in the fresh state and were regarded as a perfume, flavoring agent and spice. The juice was employed medicinally against a wide range of symptoms and diseases, especially gynecological ailments-it was a true "multi-purpose species" in the sense of modem economic botany.
It appears that Silphion was found only in the dry hinterland. Attempts to cultivate it seem to have failed, so wild plants remained the source of supply. No reasons have been given for its disappearance although overharvesting is considered to be at least one reason for the dramatic decline in its use and final extinction as an economic resource. What we have is an example of overharvesting and probable extinction of an ancient medicinal plant. Silphion reflects both the potential wealth through plant utilization and the possible risks and downfall through overharvesting.
Source: IUCN. Medicinal Plant Conservation Newsletter. 1995
For historic (if not biological) reasons, the majority of medicinal plants used in developing countries are located in specific ecosystems. Prohibiting wild collections in these locations could devastate many poor families by cutting off their source of income. It is therefore important that education programs that justify the need for regulations governing in-situ conservation and collecting be developed. The local people should participate in this and the efforts should be linked to ex-situ conservation and cultivation programs that would provide an alternative source of income (or perhaps an equal income from smaller harvest through such means as improved quality control).
In-Situ Conservation. The protection of medicinal-plant resources was not identified as a major concern of conservation organizations until 1984.10 Four years later, the Chiang Mai Declaration recognized medicinal plants as an important component of the globe's biota. It noted that these plants are an essential part of primary healthcare in most of the world; and it viewed with alarm the rapidly increasing loss. The Global Biodiversity Strategy recognized the importance of conserving medicinal-plant biodiversity. Its socalled "Action 40" cals for the development of traditional medicines to ensure their appropriate and sustainable use, and "Action 41 " promotes recognition of local knowledge, particularly medicinal healers. "Action 67" specifically mentions medicinal plants as a key group deserving increased attention. At the Rio Conference in 1992 the Convention on Biological Diversity ratified these action items.
Nonetheless, only a few countries seem to have pursued their obligations regarding medicinal-plant conservation. One of these is Sri Lanka, where the government has for a long time implanted in its people a strong pride in their natural heritage. Sri Lanka is a good example for other -countries to follow. Its flora and fauna enjoy a high level of protection, with over 400 reserves set aside for their conservation. 14 Stringent laws apply in these reserves. The government has an aggressive policy of in-situ conservation to save valuable species, and in particular medicinal plants. This action was, in part, linked to the rapid resurgence of Ayurveda following independence and the demand for medicinal plants for Ayurvedic drugs. A Ministry of Indigenous Medicine was established in 1980. In 1986, the World Wide Fund for Nature (WWF) funded the Conservation of Medicinal Plants of Sri Lanka with the objective of establishing an aggressive policy of in situ conservation to save valuable species from extinction. The World Conservation Monitoring Center (WCMC) provides services to CITES. The CITES database is the largest of its kind, currently holding some two million entries on trade in wildlife species and their derivatives.
WCMC is the only organization that gathers, analyzes and provides information on plants threatened with extinction on a global scale. The Centre is aware of the growing need to protect and conserve medicinal plants. Because of the potentially large number of medicinal plants requiring protection and the limited funds available categorizing medicinal-plant species the following characteristics could be used to set priorities:
· commonness or rarity;
· means of propagation;
· sensitivity to environmental conditions;
· plant parts used;
· properties and medicinal uses; and
· community knowledge and use.
A partnership between WCMC and the World Bank established in 1995 will provide full biodiversity data mapping services to the World Bank; seek to extend these services to GEF partners in UNEP and UNDP; capture and mobilize data deriving from investments in biodiversity; repatriate data to the developing world; build capacity for biodiversity information management in the developing world and strengthen information networks. Being able to access medicinal-plant data will enhance the decision-making process regarding protection, research priorities, management objectives, and polices to yield best results using ever scarce financial resources. It is on the basis of such information medicinal-plant diversity can be preserved in situ, successfully sustained, and ensure the germplasm for long-term ex-situ conservation and cultivation.
Ex-Situ Conservation. In 1989 the Botanic Gardens Conservation International (BGCI), in collaboration with IUCN and WWF, published The Botanic Gardens Conservation Strategy as a guide for the development of botanic garden roles in biodiversity conservation. It has developed a computer database listing rare and endangered plants in cultivation in about 350 botanic gardens worldwide, which is used to foster networking and linkages. BGCI considers medicinal plants a priority area for botanic gardens for the future. In July 1995, BGO launched an appeal for funds to establish an effective network of botanic gardens for medicinal plant ex-situ conservation and to strengthen the capacity of botanic gardens in developing countries. The first such gardens will be established in Colombia, Haiti, Uganda and Vietnam.
For many medicinal plants, cultivation is the main hope for maintaining supplies at today's levels. The wild resources are decreasing, the supply fluctuating in an unstable manner, the quality control is inadequate. Additionally, the botanical identification of the specimens is often suspect-sometimes because of fraud and other times because of genuine mistakes. Different species of plants (with wholly different chemical constituents) often look alike to the person handling the dried materials, and even sometimes to the gatherers themselves. The people handling the samples may he unreliable, and the chances for adulteration are legion.
Through the process of cultivation, the various plants can be increased on a controllable and sustainable basis, the quality can be better assured, the species identification made secure. In addition, there are possibilities for improving the crop genetically based on the level and mix of ingredients that have the medicinal effects. Yields can be manipulated by agronomic means, such as fertilizer and pest control. Finally, the handling of the materials can be regularized and the possibilities of adulteration reduced.
But all of this is mostly untapped as yet. While the domestication and cultivation of medicinal plants is several thousand years old, it is apparent that most agriculture ministries in developing countries play little role in cultivating medicinal plants. The present source of the raw materials for the pharmaceutical industries, traditional health practitioners and family users is met basically from wild sources, including places such as field borders, marginal, remote, and waste lands where the wild vegetation is left to grow unattended. The demand is also met by cutting forest trees or uprooting herbs and shrubs on nominal payment or on an unauthorized basis. A much greater awareness needs to be created among agriculturists that cultivation is the primary means of reversing the impact of unsustainable harvesting practices of wild populations.
Palevitch (1991) compared collection versus cultivation for eight important considerations. In light of the continuing loss of biodiversity, the relative advantage of cultivation is even more pronounced. While millions of dollars are invested in supporting food and other crops, little is spent on supporting the world's medicinal-plant resource base. Nevertheless, isolated medicinal-plant breeding programs have already produced a number of high yielding cultivars.
The efforts of the medicinal-plant breeder should be aimed at increasing the final yield of the active compounds and enhancing the metabolic functions that result in their accumulation. There will be difficulties as our knowledge of medicinal-plant genetics and physiology is poor, and we know less about the biosynthetic pathways leading to active ingredient formation for which these plants are valued. Another difficulty is that perhaps certain subsidiary compounds must also be present for the herbal cure to be effective.
An especially inhibiting factor in the breeding research is the variability of medicinalplant populations. Many populations found in their natural habitats are not balanced in terms of chemical characteristics and active compounds. Selective breeding of medicinal plants may follow several lines, including: random selection in populations; landraces with specific chemical characteristics; selection of clones; and hybridization. Commercial cultivation of medicinal plants demands strong and continuing attention to these diverse fields.
The farming of medicinal-plant is coming into a new stage of development that could lead to it becoming a major employer of local labor and an instrument to poverty alleviation in the developing countries. The efficiency and success of medicinal-plant cultivation will depend on the productive ability of plant material and collaboration between researchers and local peoples to enhance and sustain that production. Basic questions that need answers include:
· Is the plant suitable for cultivation?
· What are its ecological and agronomic requirements (light, moisture, soil, etc.)?
· Does it tolerate intra- and interspecific competitors?
· What insect pests, and plant pathogens are likely to attack it?
· Will harvesting be a problem?
· How well will it store without loss of therapeutic activity?
· Can it be easily processed (purified, packaged, and shipped without losing efficacy)?
Forest products are these days being divided into two categories: (i) timber products and (ii) the so-called "non-timber forest products" (NTFPs). Medicinal plants are in the NTFP category and may be considered as non-domesticated crops. Little attempt has been made to objectively assess these natural resources in forest industries. Principe (1995) has suggested that an estimate of medicinal-market value is more easily characterized in forest ecosystems as people can more readily visualize the range of benefits of forests than other ecosystems. Therefore a proper assessment and evaluation of those plants endemic to the forests is a necessary priority to provide acceptable estimates for policy appraisals, research needs and sustainable forest management programs.
At present many important and potentially important forest medicinal plants are destroyed or left to go to waste during logging operations. The forest sector, as a supplier, has little knowledge or appreciation of their value. A notable case in point is the destruction of the small yew trees in the forests of the Northwest of North America. They were long considered useless "weeds" but now provide the current drug of choice against a number of deadly cancers.
Given such discoveries, it is increasingly recognized that the forest sector must reexamine its short-term and long-term objectives and develop a multiple-product management plan that accounts for NTFPs as well as timber products. In the production of forest medicinal plants there is an opportunity for foresters, the pharmaceutical industry, and local practitioners of traditional medicine to work together to their mutual benefits.
The need to conserve and protect the world's medicinal plants is required not only for man but also for his domesticated animals. In fact all biota, wild and domesticated, within the global ecosystem probably depends at least in part on plants that sustain health.
It has of course long been known that certain plants cause farm stock to be sterile or to abort. Those conditions cause great economic losses in terms of milk, meat and progeny.
Only now, however, are veterinary scientists beginning to study this with conviction and deep interest. The wild species of the Animal Kingdom, no doubt utilized the medicinal powers of plants long before humans appeared on the scene. But herdsmen quickly learned about the value of these species. Centuries of observation and experience have resulted in a rich storehouse of ethnoveterinary knowledge and technique among stockculture peoples. Today, for those cultures where stockraising forms a vital part of their livelihood plants are a primary source of prevention and control of livestock diseases. It is thought that the percentage of animals dependent on medicinal plants is greater than the figure of 80 percent that is given for humans. In some traditional medical systems, human and animal healing are not differentiated. The herbal treatments often overlap and might be administered by the same persons.
Delivering veterinary services to pastoralists can be as difficult as delivering public health and other basic services and far, more complex than for settled peoples. Nonetheless, as traditional medicine is experiencing a revival in human medicine so is the veterinary sector, During the past decade, FAO has commissioned a number of reports on the status of veterinary medicine in Asian countries. All found that ethnoveterinary practices could be usefully incorporated in animal-health services.
Globally, veterinary medicine has followed the industrial countries prejudice for technology over traditional knowledge and self-sufficiency. Happily, the revival traditional medicine is experiencing is occurring in both human and veterinary medicine.
Box 2: The Use of Plants in Animal Medicine
There are many known uses of medicinal plants in the healthcare of livestock in developing countries. A sampling includes:
· In France farmers hang henbane
(Hyoscymus niger) in sheep pens to combat sheep pox.
By 1991, 27 WHO collaborating centers for traditional medicine had been established worldwide to strengthen national efforts in research and development. The network also serves to collect and disseminate information on both useful and harmful traditional practices. In the early 1980s, FAO compiled an initial list of 22 medicinal plants, used as raw materials for drug production. This work has continued and is coordinated by the FAO collaborating center, the Research Institute for Medicinal Plants, Budakalasz, Hungary. The FAO Non-Wood News Bulletin, first published in 1995, provides a wealth of information on medicinal plants (although, given the state of knowledge, much of the information is neither consolidated nor validated).