The end of Ethnobotany?

[Santiago Madrinan]

Dear Taxacomers,

An article of interest to the list has appeared in the most recent issue of
The Economist (Feb. 20-26, 1999).

Looks like "Ethnobotanical screening" was just a modern day version of the
"Doctrine of Signatures"...

Below the URL to the article and text transcript:

http://www.economist.com/editorial/freeforall/current/st4723.html

THE ECONOMIST

SCIENCE AND TECHNOLOGY

The end of Ethnobotany?

Shaman loses its magic

 IT WAS a tree-hugger=B9s dream. Save the rainforests. Respect and honour th=
e
knowledge of the people who live there. And still make money for your
shareholders. Unfortunately, it doesn=B9t look as though it is going to work=
=2E
Earlier this month, Shaman Pharmaceuticals, the leading proponent of the
"ethnobotanical approach to drug discovery" an attempt to identify the
active molecules in folk remedies, in order to turn them into modern
prescription medicines threw in the towel.

 Shaman=B9s failure to convert old-wives' tales into drugs (though it is
still pursuing the idea in the less rigorously regulated field of herbal
dietary supplements) probably marks the end of the sort of selective
"botanising" that started the pharmaceutical industry, when the
pain-killing properties of willow bark led to the invention of aspirin.
Merck, one of the world=B9s biggest drug companies, spent ten years trying t=
o
extract and develop the active principles from Chinese herbal remedies. It
failed too. Other firms are downgrading the role of traditional medicine
when screening plants for useful substances. Instead, they prefer the
automated mass-screening techniques originally developed to deal with the
artificial products created in vast numbers by modern combinatorial
chemistry.

 It is a popular misconception, probably generated by such pharmaceutical
celebrities as quinine, and fed by environmentalists keen to preserve
rainforests, that those forests abound with billion-dollar blockbuster
drugs just waiting to be discovered. The facts are different. Between 1960
and 1982, America=B9s National Cancer Institute (NCI) and Department of
Agriculture (DOA) collected 35,000 samples of roots, fruits and bark from
12,000 species of plants. Only three significant products were discovered
in them.

 Taxol, Camptothecin, and homoharringtonine have all proved useful as
anti-cancer drugs, but they do not suggest that the forests are teeming
with pharmaceutical opportunities. And more recent collections by the NCI
and DOA (gathered between 1986 and 1996 from South America) have been even
more disappointing. As yet, not a single drug has emerged from them.

 Shaman tried hard. It sent teams of physicians and botanists into the
rainforests of more than 30 countries in Asia, Africa and South America.
They collaborated with local healers to identify plants with medicinal
properties. And the firm abided by the standards laid down in the
Convention on Biological Diversity that was signed in 1992 in Rio de
Janeiro. This sought to highlight the economic value of regions rich in
species, and ensure that local people benefited.

 That meant that, in exchange for the knowledge it received, Shaman
provided a payment of up to $8,000 (or the equivalent in goods and
services) to the healer=B9s community. It also promised long-term benefits i=
f
a drug was actually developed from one of the plants concerned.

 But although short-circuiting the screening process by starting with
medically proven plants may have looked a smart move ten years ago,
screening technology has got better and better. It will soon be possible to
check molecules for promising biological activity at a rate of 100,000 a
day. It may look more elegant to ask the locals, but screening everything,
regardless, is now faster and cheaper.

 On top of that, the folk healers=B9 concerns are not necessarily those of
drug companies. The former are frequently preoccupied with curing parasitic
infestations unknown in the rich countries that provide the companies with
their markets. They are much less adept at diagnosing and treating diseases
such as cancer, where the real money is to be made.

 There are some areas of overlap, however. Shaman had seemed to be making
good progress on type II diabetes (which is untreatable with insulin).
Diabetes is a disease that is recognised in many cultures because
sufferers, whose blood-sugar levels are out of control, tend to pass
sugar-rich urine. By using ethnobotany to provide the raw materials,
Shaman=B9s researchers were able within four years to isolate 30 compounds
that lowered blood-sugar levels enough to make them look promising as
anti-diabetes drugs.

 Whether any of those molecules would have made it through the regulatory
process will probably never be known, but it was that process that
eventually brought things to a halt. The drug in question, Provir, was
actually intended as an anti-diarrhoea treatment (diarrhoea being another
problem that the rich and poor worlds share).

 Provir was particularly designed for AIDS patients. That did not save it.
When the Food and Drug Administration, which approves medicinal drugs in
America, told Shaman it would have to conduct a further series of clinical
trials on the stuff, it gave up. The trials would have delayed things by 18
months, and cost tens of millions of dollars that the company could not
afford.

 The end of Shaman=B9s adventure does not, however, mean that the rainforest=
s
have lost their allure completely. Merck, for example, has a long standing
arrangement with Costa Rica to prospect for drugs in that country=B9s
forests. The firm also collaborates with the New York Botanical Gardens to
collect plants from all over the world. But the wisdom of the ages will not
be coming with them. Modern technology has won.

--
Santiago Madrinan, Ph.D.

Dept. Ciencias Biologicas         Tel:+57(1)286-9211, ext. 2729
Universidad de los Andes        Fax:+57(1)284-1890
Apartado Aereo 4976
Santafe de Bogota, D.C.
COLOMBIA