Goals
Background & Significance
There are an estimated 265,000 species of flowering plants on our planet. Only 0.5% of them have been studied exhaustively for their chemical composition and medicinal value.(1) Confronting a rain forest, the modern botanist stands as humbled by his ignorance as an astronomer pondering life among the galaxies.(2) On the other hand, indigenous people living in harmony with the plant species of the rain forest can describe specific uses for anywhere from 49% to 82% of the trees in their environment. (3) Utilizing indigenous knowledge of potentially useful medicinal plants can substantially increase the likelihood of finding plants with identifiably active phytochemicals.(4) Unfortunately, even as the rainforests are being clearcut, knowledge about the utility of native plants, particularly as medicines, that has been refined over scores of generations is probably in greater danger of extinction at the present time than are the plant resources.(5) The empirically obtained knowledge of the medicinal uses of plants has evolved through centuries of isolated indigenous use, modified by contact with European cultures as the colonial period ensued. There remain few, usually elderly, people who still retain the knowledge handed down from one generation to the next about the identification, collection, preparation and indications for use of rainforest medicinal plants. Unlike the stereotype of the secretive, hostile "witch doctor" sometimes portrayed in literature, recent researchers have "had an opportunity to observe those personality traits which epitomize the traditional healers . . . tremendous self-confidence, great sense of humor, a strong spiritual foundation, an abiding humility, a great respect for the natural world and its ability to sustain life, and a sense of caring more for the welfare of others than for their own."(6) Unfortunately, as the North American lifestyle intrudes more deeply into less technologically advanced cultures, the younger generation have less inclination to pursue the tedious task of apprenticeship to one of the elders. It is our responsibility, then, to preserve the best of the cultures we have overwhelmed with video images, blue jeans and rock & roll. Fortunately, "most traditional healers are thrilled to know that they can help to pass the torch of healing to another generation. They are deeply concerned that the young people of today care little about healing plants and 'old-fashioned' ways. From every corner of the globe, we learn that the fires of traditional healing are now, in the twentieth century, down to a mere bed of embers and faintly glowing coals."(7)
Economic models of annual yield, market value and net revenue comparing harvesting rain forests for timber to sustainable harvesting of fruits and latex from the same trees demonstrate comparable dollar yields, not taking into account the value of biodiversity and other nonmonetary values.(8) Comparison of tree farming versus cattle pasture demonstrate the former to be more profitable.(9) Sustainable harvesting of rainforest medicinal plants has been shown to provide yields of $564 per hectare up to $3327 per hectare depending on the age of the forest.(10)
Even if it might be economically feasible to cultivate rainforest medicinal plants, why should we bother? Don1t we already have enough synthetic pharmaceuticals to adequately manage most of our common and serious diseases? Many people, including physicians and other health care providers, don't realize that approximately 25% of those commonly used drugs are derived from plant sources. Since plants have evolved defenses against predation by other organisms, they have had eons to develop and select chemicals which have very potent and specific biologic activity in the animals which might otherwise consume them. "Many of the human body's powerful reactions are a direct response to plant alkaloids, a class of chemical compounds most common in tropical plants. Alkaloids . . . have had a major impact on every culture--if not every person--on the planet. They provide everything from the kick in our morning coffee (caffeine) to the addictive compounds in our most dangerous drugs (cocaine, heroin, and nicotine), the toxic principles in some of the deadliest poisons (strychnine and batrachotoxin), the analgesic effects in our most potent painkillers (codeine and morphine), and the mental pyrotechnics in some of the most powerful hallucinogens (mescaline and psilocybin)."(11) In addition, the complexity of the bioactive molecules produced by plants(12) make the inexpensive synthesis of such compounds unlikely, and emphasize the importance of maintaining adequate natural resources.
A major danger of the deforestation which has escalated significantly during this century is that unique medicinal plants will be lost even before they are fully understood. Even plants whose utility is known can be wiped out. One of the first drug plants to be rendered extinct in the ancient world was silphium, a birth-control agent highly valued by the ancient Romans. Its employment as a contraceptive was so widespread that this difficult-to-cultivate plant no longer existed in the Mediterranean area, or anywhere else, after the third century A.D.(13) Even the Pacific yew tree, the source of taxol, the most recently 3discovered2 plant medicine for ovarian and breast cancer, was formerly used by Native Americans.(14) The implications of the loss of plant-based medicines go far beyond the potential loss to scientific knowledge, development of new pharmaceuticals or cures for deadly diseases. The World Health Organization recognizes that if the vast majority of people living in the world today are going to receive basic health care, it is imperative that we preserve and encourage the appropriate use of traditional medicines.(15) One flaw in much of the published ethnobotanical work is the difficulty in translating diagnostic categories from traditional medicine into Western scientific terminology.(16) We will seek to achieve some consistency in description based on diagnosable conditions treated by both traditional and Western healers.
Costa Rica has a rapidly vanishing indigenous population; there are approximately 40,000 individuals in eight separate ethnic groups.(17) Archeological work has been performed in the Lake Arenal region which indicate a remarkably stable, ecologically balanced and prosperous civilization dating back to at least 3500 BC.(18) Macrobotanical remains found during archeologic study demonstrate both cultivation of food crops and gathering plants from the local environment, including at least one non-food plant family which may have been used medicinally.(19) We will try to develop collaborative interchanges with the remnants of the Guatuso/Maleku culture, to learn more of their current health care needs and systems.
Research Objectives
Answering the above questions will help determine whether there is scientific, cultural and economic support for the hypothesis that utilizing land in the Lake Arenal area for cultivation and harvesting of medicinal plants can be self-sustaining. The objective is to reinforce incentives to preserve and reforest areas on the margins of existing native forest and cleared land. If doing so can be shown to be economically feasible, the trend toward clearcutting trees for lumber and using the cleared land for cattle pasture could be counteracted. In addition, the preservation of local knowledge about otherwise endangered plant species could be shown to be desirable and valuable, thus creating greater likelihood of apprenticing younger members of the community and/or environmentally-minded outsiders to learn the ethnobotanical knowledge base before it dies out with the older generation.
Methods:
We will review the available literature regarding the traditional use of medicinal plants in the area. The only written record of the remaining indigenous culture has been translated from Maleku to Spanish and is being translated into English.(20)
We propose to interview and record on videotape local informants regarding the gathering, preparation and use of selected plant medicines. We will attempt to obtain information from the few remaining descendents of the original inhabitants (the Guatuso/Maleku in Tonjibe, Margarita and Palenque del Sol). The format for cataloguing the ethnobotanical information will follow standard published procedures.(21) We will summarize the consensus of medical uses of selected plants. We will categorize the sources of medicinal plants as gathered, cultivated or acquired from outside sources. Of those that are gathered locally or cultivated, we will try to determine the optimal conditions for locating, growing and harvesting the plant material. Selected plants will be identified by experts based on voucher specimens(22) to determine as accurately as possible their scientific classification.(23) Chemical constituents which have been characterized will be described and their known biological activity, if any, listed. We will attempt to have unique or otherwise interesting plants analyzed chemically. We will also survey local markets to determine which medicinal plants are currently being sold in the local area and possibly on a national basis. We will continue to network with other regional cooperatives and farms growing medicinal plants for sale or export.
We will incorporate the cultivation of selected medicinal plants as part of our reforestation of cleared land adjacent to the rainforest. We will study reforestation by using forest litter as a source of mixed indigenous seeds and attempting to recreate an environment close to the original for plants which require specific conditions (i.e. epiphytes, shade, moisture, etc.) We will document the stages of regrowth photographically and try to interfere as little as possible in the selection process except for removing dense African grasses which would otherwise overgrow woody seedlings.(24) We will tag and maintain a site map for the medicinal plants we intentionally cultivate. We will attempt to document predation by insects, birds or animals, if any, which may result in poor growth. Rather than the "farming" of a few species, we will seek to increase the biodiversity of the land use. Similar work at the boundaries of Braulio Carillo National Park has demonstrated former pasture land supporting up to 80 different species after 28 months of regeneration.(25)