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The Medicinal Rainforest
Dr. Sharon Shaw Elrod
Maura McAuslan
The importance of the rainforest has long been overlooked. It is only in recent times that the world as a whole has seen and acknowledged its immense significance. Tropical rainforests are home to half the world's plant species and cover less than 6% of the Earth's land area.
It has become imperative that all humankind understand the contribution the rainforests and its species make in our lives. Most of us recognize that they provide us with coffee, sugar, fruit and cocoa. We also acknowledge that they provide us with nearly half of our oxygen supply. What is not commonly known is that they help to supply us with a great deal of our pharmaceutical supply. One quarter of the world's medicines are derived from rainforest plants and 37% of the United States' prescribed medicines have active ingredients that are derived from the rainforests.
This may not seem like a big deal until you realize how quickly the rainforests are disappearing. Many rainforest species are endemic and once they are lost, they are gone forever. Experts say, each day 137 species are lost to the destruction of the rainforests (Leslie Taylor, 2004). As these species vanish, so do the possible cures they could have offered. Rainforest plants have been used for generations for medicinal purposes. From headaches to malaria, arthritis to leukemia, even in childbirth, medicinal plants have served a great purpose to those suffering.
While western societies have shied away from these remedies and have moved to more advance medicines, developing countries are still largely dependent on traditional medicines, based on medicinal plants and animals, for their primary healthcare. Western society is starting to stop and take a second look at medicinal plants that could help them improve their quality of life.
Pharmacopeia History
It was once said that "Mother Nature... is an infinitely more ingenious and exciting chemist" (Taylor, 2004). Plants often protect themselves by producing chemicals that are toxic to certain species. When ingested by humans these same toxins can have different effects - nutritious, poisonous, or therapeutic. The chemicals in plants that produce the medicinal effects are called phytochemicals. These are often characterized by a bitter taste. Anthropologists believe animals evolved a pattern of seeking out bitter plants as a response to illness. Just as animals learned to, humans have also learned to seek treatment from plants.
Documentation of the use of medicinal plants dates back to prehistoric times. Neanderthals living 60,000 years ago left evidence of the use of medicinal plants, including species of plants that ethno-medicine uses today. Evidence of medicinal herbs is found in the Lascaux cave paintings and date between 13,000 and 25,000 BC. Imhotep, the first physician known by name, may have had the first written medical plant cures on papyrus scrolls in 2,900 BC.
As recently as the late 1800s, plants were still the singular form of accepted pharmacological treatment for disease. John Rudolphy's Pharmaceutical Director of All the Crude Drugs Now in General Use; Their Etymology and Names in Alphabetical Order, (2nd edition, 1872) is a botanical list of all the plants known at that time which were used to treat physical ailments. No other chemicals were employed in the field of medicine; plants were the only 'drugs' used to treat illness.
It was not until the early 20th century that researchers began to synthesize drugs. Aspirin, often considered in the western world as a 'wonder drug,' even has its ties to plants. Tribes of Native Americans, as well as the ancient Greeks, used extracts of willow tree bark (Salix sp.) to treat pain which lead to the discovery of the compound acetylsalicylic acid. This is the wonder drug’s painkilling ingredient. A large portion of the world's modern medicines have been synthesized from plant chemicals in much this same way.
Biodiversity in the Rainforest
In spite of the movement over the past century from medicinal plants to pharmacologically produced medications to treat illness, rainforest plants still provide us with a the basis of modern day medicines. Today one-quarter of all medications come from rainforest plants, although less than one percent of the rainforest's millions of species have ever been studied.
Current research by the National Cancer Institute (NCI) has identified more than 3,000 plants that are active against cancer cells and 70% of these species are located in the rainforests. According to experts, if there is a cure to cancer or AIDS, it will be found within the rainforest's biodiversity.
Consider the damage: in 1950 rainforests covered 15% of the land surface, therefore in half a century we have lost half the world's rainforest. If our current pattern continues, we will lose the rainforest in another 50 years! Estimates suggest we lose 50,000 species a year due to the destruction of the rainforests. This is a staggering amount of lost biodiversity.
The loss of these species could have a catastrophic effect on human life. For example, the Madagascar rose periwinkle (Catharanthus roseus) had a huge impact on the medical community. The two drugs that are derived from this periwinkle are monumental to those with Hodgkin's disease, leukemia, and other blood cancers. Survival rates for childhood leukemia alone rose from 10% to 90% with the use of the periwinkle's derived drugs. This species was endemic to Madagascar and is currently extinct there due to deforestation. It has been cultivated in other places since, but had we lost this species before its potential was known, survival rates could still be at 10% for this illness.
By losing so many species each year we may be losing, or have already lost, the cures and treatments to many diseases. There are literally hundreds of plants that already hold value for the field of medicine and pharmacology. Most likely, there are hundreds, perhaps thousands more that are yet to be discovered.
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Rise of Alternative Medicine
in Western Culture
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In today's society, a greater number of people are turning to complementary and alternative medicine (CAM) for their health needs. Harvard Medical School (1997) estimates 50% of U.S. adults 35 to 49 years of age use at least one type of alternative therapy. Between 1990 and 1997, there was an increase in the use of herbal supplements in the United States of an astonishing 380 percent. CAM consists of a number of alternative practices including ayurvedic medicine, traditional Chinese medicine, homeopathy, naturopathic medicine, chiropracty, and vitamin therapy.
Why is there such a strong interest in CAM? Conventional medicines hold a valuable purpose for emergency medicine, but people are finding it lacking for long term care and prevention. CAM requires a patient to take an active role in their health, in contrast to conventional medicine's passive role. In total, 80% of the world's people are finding their basic health care outside the hospital and with some form of alternative medicine.
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Plant Chemicals
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Plants produce a vast array of chemicals. The chemicals that are non-nutritive and have protective or disease preventing qualities are called phytochemicals.
Many of the chemicals are secondary metabolites that are not necessary to the functioning of the plant. They consist of four groups including alkaloids, phenylpropanoids, flavonoids, and terpenoids. These chemicals are used to help the plant defend itself from predation and to disperse its seeds.
The largest of the secondary metabolites are the alkaloids. They appear in nearly 45% of tropical plants and are characterized by a bitter taste.
Some examples of alkaloids are caffeine, cocaine, nicotine, opium, and quinine. An example of how an alkaloid works is some plants produce nicotine which is a natural insecticide.
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Ending Biopiracy
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Many communities do not reap the benefits when their country's plants are discovered and used by drug companies. For instance, the Madagascar periwinkle's drugs are worth over $100 million a year, but Madagascar saw none of this money until the patent expired.
New attitudes are helping these countries, many still developing, prosper as well. The drug Prostialin, which was isolated from a Samoan rainforest tree, may be effective against HIV. The NCI has guaranteed part of the money from this drug's royalties will be returned to the Samoans. The Samoans have since established a national park to encourage healers to use medicinal plants in a sustainable way (Rhett Butler, 2006).
While this case may be the exception to the rule, it will hopefully serve as an example to bioprospecting companies.
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