Cinchona is a shining example of an ecosystem service - the service known as - pharma-cog-nosy. Pharma what? OK, pharmacognosy is a helluva word but it describes a group of benefits that we derive from nature that we couldn't do without - life saving drugs such as quinine.
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Background
Of the estimated 350,000 vascular plant species known to science, 7% (c. 26,000) have documented medicinal use.1
The genus Cinchona comprises 20-40 species of tropical evergreen trees and shrubs, which are distributed through Central and South America from Costa Rica to Bolivia. Cinchona is in the same family as Coffea (the source of coffee). Common species are C. pubescens, C. calisaya, C. macrocalyx and C.officinalis.
Ecology
Cinchona trees provide nutrition for a range of leaf-eating insects and also for stem borers. They also host a wide range of parasitic fungal species. They are pollinated by bees and flies. The plants are also involved in a mutualistic relationship which allows nutrient exchange between a fungus and the roots of the tree.
Distribution
Generally, in its natural range, Cinchona trees need warm climates with high precipitation and humidity almost all year round for optimal growth. It grows best in rich volcanic soils. A common species, Cinchona pubescens grows at altitudes between 300 and 3300 m, in a montane community. Annual rainfall for an optimum growth is around 2,000mm / year.
Some Cinchona species have been deliberately introduced to other countries including India and South East Asia, Australia and Papua New Guinea and tropical regions of Africa as, for many years, it was commercially harvested for its quinine rich bark. It can become invasive under some conditions - its seed dispersal mechanism is very effective, and natural predators may not be present in other countries.
Services
The bark of Cinchona trees contains a chemical called quinine, which the plant has evolved as a defence against insect predation, although several insect larvae have managed to make it their primary food. Quinine has been used by indigenous people of South America as a cure for fevers for centuries. In the mid 17th century, it was introduced into Europe by Jesuit missionaries as a cure for malaria. Malaria has been a major health problem in many parts of the world. Even with advanced medical knowledge in the 20th century, it was responsible for 150 - 300 million deaths. It is caused by blood borne parasites which are transmitted by mosquito bites. Quinine, and hence cinchona bark, has had a great strategic significance in the rush by European countries to colonise the New World. Having enough quinine to protect soldiers from the ravages of malaria conferred a valuable military advantage. Hence the introduction of Cinchona spp. through out different countries in the world. It has, in fact, become invasive in some situations, due to its resilience to physical damage and its effective seed dispersal.
Quinine was used as "the treatment" for malaria up until the latter half of the 20th century but has now been replaced in some situations with artemisinin (derived from the plant wormwood) which does a similar job without some of the complications that can arise from use of quinine. Various forms of products derived from cinchona and wormwood have been manufactured and are often used in combination. Testing these combinations is ongoing, with further research into which combinations work best in which circumstances.
Quinine is commonly used as a flavouring in bottled, carbonated water, marketed as tonic water. It is also a component of the popular alcoholic cocktail, gin and tonic.
As well as quinine, Cinchona plants produce a range of other chemicals. Traditionally, parts of the tree have been used to treat
- stomach problems such as promoting the release of digestive juices; and treating bloating, fullness and stimulating appetite
- blood vessel disorders including hemorrhoids, varicose veins, and leg cramps
- mild influenza, swine flu, the common cold, and fever, cancer, mouth and throat diseases, enlarged spleen, and muscle cramps
Also used externally in eye lotions to numb pain, kill germs, and as an astringent. Cinchona extract is also applied to the skin for hemorrhoids, ulcers, and stimulating hair growth
Summary of services provided for us
- Besides the services that all green plants provide (photosynthesis to produce oxygen and remove CO2 from the atmosphere), the Cinchona genus has given us a drug which has saved the lives of million of humans who would have died of malaria. It is still in use.
- Quinine, derived from Cinchona, is also a worldwide popular drink flavouring.
- Services for ecosystem stability
Threats to the services?
- Cinchona trees are threatened in Peru due to land clearing for agriculture, and soil degradation.
- Some cinchona species in the wild in Ecuador have become rare and hard to find. Of 9 species listed by the IUCN, 2 are classified as Vulnerable and 1 as endangered.
- The disappearance of wild specimens means that there is reduced genetic material and therefore variation in among the remaining trees. Plants in other parts of the world do not reflect the full diversity of species from this genus and have been bred purely to enhance one single characteristic of the plant.
What can we do to retain these services?
There are some efforts being made to protect trees in the wild but more funding is needed to explain and publicise reasons for preserving Cinchona populations.
Dig deeper
- https://phys.org/news/2018-10-peru-danger-national-cinchona-tree.html
- The quest for cinchona video
- https://www.bbc.com/travel/article/20200527-the-tree-that-changed-the-world-map