 
Collecting species: a “bioprospector” on the job in Costa Rica.
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Nature’s medicine
chest
Relieving pain
18171: morphine is extracted from poppy flowers.
Treating inflammation
1829: aspirin is extracted from willow bark.
Regulating heartbeat
1868: digitaline is extracted from digitalis.
Fighting malaria
1820: quinine is extracted from cinchona bark.
1972: artemisine is extracted from artemisia.
Preventing the rejection of transplanted organs
1970: cyclosporin is extracted from a Norwegian mushroom.
Fighting cancer
1958-1965: the derivatives vinblastine and vincristine are extracted from the
Madagascar periwinkle.
1971: taxol is extracted from the Pacific yew.
1980: taxotere is extracted from the European yew.
1. Dates refer to the
isolation of the active ingredient, usually 10 to 15 years before the drug is marketed.
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Pharmaceutical companies
are taking an increasing interest in plants, insects and bacteria. But from nature
to clinical trials, the road is a long one
 In Madagascar’s Isalo mountain
range, the guide stops. At his feet, a tiny flower displays its pink petals. “This
plant is good for cancer,” the man says proudly. Long consumed to relieve hunger,
the Madagascar periwinkle was first described by the French botanist Etienne de Flacourt
in 1645. Then, in the 1960s, it was discovered to be effective in treating cancer.
Humans have always found substances in nature to relieve their suffering and cure
their ills. In developing countries, 80 per cent of the population relies on traditional
remedies extracted from plants to treat illnesses. Some “modern” drugs that contain
a single active ingredient rather than a mixture of substances owe their existence
to natural biodiversity. Morphine, quinine, digitaline and 116 other drugs made from
plants are in widespread use, according to American pharmacologist Norman Farnsworth.
An estimated two-thirds of the drugs sold in pharmacies are of natural origin. They
account for some $30 billion in sales every year.
There is an urgent need for therapeutic research to find new treatments that can
be helpful in fighting recent, emerging diseases such as Aids as well as overcoming
resistance to current treatments for cancer, malaria and bacterial infections. Researchers
are following several leads, such as gene therapy, which is still in its earliest
stages, and drug design. With the advent of molecular biology, they have begun designing
tailor-made drugs. Knowing the shape of a given biological “lock”, they use computers
to design the molecular “key” that may trigger the mechanism resulting in a cure.
This method works in theory, but in practice it is extremely complicated to create
ex nihilo an artificial substance that is not found in nature. Hence the advantage
of combining natural molecules that result from 4.5 billion years of evolutionary
development.
Recent successes have confirmed the value of using substances from nature. The discovery
of cyclosporin, an immunosuppressant, in a Norwegian mushroom has led to decisive
progress in preventing the rejection of transplanted organs. Researchers working
for the American pharmaceutical giant Merck & Co. have recently detected a chemical
component in a Congo mushroom that acts like insulin and may be used to make the
much sought pill for diabetes. At the same time, in vitro methods for detecting active
molecules have evolved. Pharmaceutical companies have giant robots capable of testing
up to 100,000 samples a day.
Calling
on local healers
Nevertheless,
in practice the road leading from plant to drug is still extremely long and fraught
with uncertainty. First, samples must be collected in strategic places, where primary
forest survives. They are located in “countries in the inter-tropical zones of Africa,
South America, Asia and the Pacific,” says Thierry Sévenet, research director
at the French Institute for Natural Substance Chemistry.
In the field, biological prospectors are following three different and complementary
leads. Scientists collecting plants at random bring back as many samples as they
can for screening by robots. But the traditional knowledge of local healers can narrow
down the search. Folk remedies have led to the development of several drugs, starting
with quinine and digitaline. Researching in the South Pacific, American ethno-botanist
Paul Cox recently studied a stem of Homolanthus nutans that Samoans prepare for the
treatment
of fevers. Chemists scrutinizing the plant found that it contains a known molecule,
prostratine, which acts upon the Aids virus. Lastly, using the chemo-taxonomic approach,
scientists probe species from the same family already reputed for containing useful
substances.
Once the samples are gathered, chemists take over, extracting and purifying substances
from the raw material in order to produce mixed or pure chemical components. Then,
the extracts are tested to determine whether they are biologically active. At this
stage, the screening process is extremely thorough. Generally, a single molecule
is kept out of 10,000 compounds analysed. Altogether, it takes 15 to 20 years from
the time the plant is gathered in the forest to the final clinical trials conducted
before a drug can be marketed.
Profit-sharing
Pharmaceutical
research is sluggish and uncertain, while the threats to biodiversity are irreversibly
and rapidly gaining ground (see
pp. 22-23).
In the face of this urgency, which coincides with rising interest on the part of
researchers, prospecting projects are being developed, despite the increasingly strong
constraints on the industry. Before the 1992 Earth Summit in Rio de Janeiro, Western
laboratories–the only ones that can afford to invest huge sums in research–drew from
the biodiversity of the Southern countries without giving them anything in return.
But in the past ten years or so, these countries have demanded a share of the profits–and
pharmaceutical companies are beginning to listen. In 1991, for the first time, Merck
& Co. paid over one million dollars to INBIO, Costa Rica’s national institute
for biodiversity, to gain access to the country’s genetic resources. If a drug is
developed, the institute will receive between two and six percent of profits, of
which half must be earmarked for the preservation of national parks. In five other
projects carried out by the United States with South American and African countries,
U.S. universities are co-operating with local ones. It remains to be seen how the
indigenous people who help in the selection of plants will be remunerated.
In the shadows of the world’s big pharmaceutical companies, smaller local laboratories
have joined the green gold rush. Madagascar’s institute of applied research has begun
a study of 12,000 native plants. Working with France’s natural history museum, the
institute has identified a substance that strengthens the effectiveness of chloroquine
against malaria. With a bit of luck, this plant from the Strychnos family will follow
the same trail blazed by the Madagascar periwinkle.
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