One reads these reports with a sense of despair. There has been much talk over the last decade, and there has been some action. But it appears to be a losing battle against powerful economic and industrial interests. It is hard to sustain enthusiasm for conservation projects when the best efforts of zealous and committed people are met with such limited success.
Amidst all the pessimism and gloom over the future of the rainforests of the Earth, one recent report provides more than a glimmer of light. The novelty of the situation is that conservation funds are being obtained from the pharmaceutical industry! The pioneer project has been launched in Costa Rica, which has given conservation a high priority over the years. Recently, this country has developed an innovative way of financing a major programme of managing, studying and preserving the wealth of plant and animal species found within its borders. The National Biodiversity Institute (INBio) is a non-profit Costa Rican organisation created in 1989 with the full support of politicians, financiers, and conservationists. In September 1991, an agreement was signed between INBio and a multinational drugs company which was based on the idea of `chemical prospecting'. INBio will identify and isolate complex chemicals produced by the largely unresearched population of plants and animals living in its rainforests, and the drugs company will screen them for medical applications. Successful products will result in royalties being paid to INBio, enabling work on the flora and fauna to continue.
According to the report in New Scientist (19 October 1991, 26-40), about 25% of medical prescriptions in the US are formulations that can be traced back to chemicals produced by living organisms. The figure is remarkably high, considering that interest has been concentrated on synthetics and microorganisms for the past 30 years. There are several indications of a shift towards products derived from plants and animals. The situation has changed for at least three reasons. First, the high cost of synthesising and investigating chemicals: it is said that 5-10,000 chemicals must be manufactured to get one new drug lead. Second, the emergence of faster screening techniques: a natural products laboratory can now screen thousands of compounds a week. Third, the realisation that a vast reservoir of potential drugs is rapidly disappearing: it is widely known that the rainforests of the Earth are under threat.
What is the explanation of this rich potential? There are extraordinary numbers of organisms in rainforests: one tree was studied in the Amazon basin and found to have 43 species of ant, which is about the same number as is found in the whole of the British Isles! These are complex ecosystems, with innumerable plant-consumers and predators. Consequently, there are seemingly innumerable defence mechanisms - mostly of a chemical nature. These are the substances targeted for investigation by the pharmaceutical industry. For example, vincristine is a multi-million dollar cancer drug derived from the Madagascar periwinkle. There are reports of a potent new anticoagulant derived from the bark of a Brazilian tree - used by the local Indians as a poison for their arrows.
The last example suggests an alternative strategy for discovering new drugs: `ethnobotany'. This approach involves communication with tribal herbal healers and shamans: finding out what substances they have used successfully. In one comparative study, the random collection of 18 plants yielded one substance worthy of further investigation, whereas an ethnobotanical collection of 20 plants yielded 5 `hits' to follow up.
It has been recognised throughout human history that medically useful materials can be extracted from herbs. For the Christian, this is a cause for thanksgiving to God. He has provided these things for our good. Why should plants and animals produce chemicals which are beneficial for man? Is it an evolutionary accident? Is there no purpose behind it all? From the Bible, we learn that man is to care for the Earth and all the works of God's hands - if we neglect this, it will be to our loss. If man keeps thinking he is the master of the world and his own destiny, he is in great danger of losing all.
We recognise the practical wisdom expressed in the collaboration between drug companies and countries possessing rainforests: our hope is that this strategy will yield many medically-useful products. It is possible that the secrets of the rainforests will be their defense against destruction. We give thanks and honour God for his created treasure-trove of chemicals. May we, as his stewards, seek guidance as to how we can be more effective in exercising our responsibilities to subdue and replenish the Earth.
David Tyler (1992)