Ethnopharmacology and ethnobotany are fundamental tools for the use and conservation of biological and cultural resources. These resources are crucial for the future of medical and pharmaceutical science and for the well-being of communities who are custodians of the knowledge.

Ethnopharmacology is the science that studies the active principles of traditional pharmacopoeia, especially medicinal plants. Since it is impossible to systematically evaluate the chemical properties of the 500,000 or so plants that exist in the world, local knowledge enables us to concentrate scientific research on certain medicinal plants, focusing the selection on the most promising species.

Since 1993, in a joint initiative with Sao Tomé and Príncipe's Ministry of Health, recognised traditional practitioners have been sharing their knowledge with a team of pharmacists and biologists. This partnership has enabled us to enrich our scientific knowledge of certain medicinal plants. The aim was to give scientific validation to traditional medicinal practices, confirming their efficacy and opening up avenues for the development of new drugs suited to local socio-economic conditions. More then 300 plant species used in local traditional medicine have so far been identified and studied. A selection was then made of the plants likely to prove most useful. The ethnopharmacological data was made available to the ministries of Health and Agriculture to help draw up a national health policy and generate wealth through the use of these local medicinal plants.

This initiative also aims to help conserve local knowledge about the use of medicinal plants. There is a growing risk that this knowledge will be lost since a good number of elderly healers have no descendants interested in carrying on the tradition. For example, Sum Pontes, a traditional healer widely respected in Sao Tomé, has supplied information that has enabled researchers to deepen their understanding of Thithonia diversifolia. This plant, which originated in the American continent, had already been studied in some depth as an anti-inflammatory and anti-diabetic treatment. However, Sum Pontes uses it to treat malaria "because it is very bitter". This therapeutic use has now been registered, for the first time anywhere in the world. The active principle responsible for the anti-malarial properties (Tagitinine C), which is of enormous potential interest, has therefore now been scientifically established and the wisdom of this elderly healer recognised. Examples such as this demonstrate the importance of ethnopharmacological data and of their publication, in this case in a book titled Estudo tnofarmacológico de Plantas Medicinais de S. Tomé e Príncipe, which documents the findings of a team of traditional healers working together with young researchers.

Cultural and biological diversity

Biodiversity guarantees the availability of a wide range of active compounds that are essential for the development of new drugs. The humid tropical forests are the world's richest regions in terms of biodiversity, but they are also the most threatened. Ethnobotanists can help conserve these resources by identifying the threatened species and sharing the information at the local and national level. Conservation does not require ambitious or grandiose projects. It can start with support and encouragement for households to grow a few priority species in their backyards or on a common plot of land.

Ethical issues

The past two decades have seen a growing interest on the part of researchers, international organisations, governments and NGOs in protecting intellectual property rights and sharing knowledge and benefits. But it has proved difficult to create adequate cross-border and cross-cultural agreements. Legal systems are complex and sometimes inadequate. There is therefore a need to consolidate agreements for knowledge-sharing by supplementing them, at each stage, with more specific accords that are adapted to specific cultural contexts, so that local capacities are rewarded and the people involved receive fair recompense.

In the case of Sao Tomé and Príncipe, all the results were first presented to the government. Three local healers, Sum Pontes, Sum Gino and Sum Costa, who supplied the knowledge that is behind the study, are cited as co-authors of the book that was subsequently published. All sales from the book, as well as other advantages that could derive from more studies in the future, will go to these three men and will help to improve their living and working conditions. The way forward is through mutual recognition of each other's role, availability and a sound code of ethics.

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