Medicinal Trees and Shrubs
Trees, shrubs and many other flowering plants have been a source of medicinal compounds for centuries. The medicines derived from the various parts of the plants are used by both conventional and alternative medicine, some have been clinically proven and others not so.
In industrialised countries, plants have contributed to more than 7,000 compounds produced by the pharmaceutical industry, including ingredients in anaesthetics, analgesics, antibiotics, anti-cancer agents, antiparasitic compounds, contraceptives, decongestants, diuretics, heart drugs, hormones, laxatives and ulcer treatments. Around one in four of all prescription drugs, dispensed by western pharmacists are likely to contain ingredients derived from plants (BGCI (Botanical Gardens Conservation International) fact sheet).
Tropical forests are the source of a large proportion of the world's recognized medicinal plants. It is variously estimated that there are between 200,000 and 700,000 species of tropical flowering plants. Such a wealth of identified species constitutes an enormous potential source of plant-derived chemicals.
Tropical forests are disappearing at an alarming rate and man is unwittingly observing the decrease of a natural resource which has been described as a 'powerhouse of evolution' and a major source of 'wild medicine'. The FAO (Food and Agriculture Organization) of The United Nations, IUCN (The World Conservation Union) UNEP (United Nations Environment Programme) and UNESCO (United Nations Educational, Scientific and Cultural Organization) have realised the implications of this steady loss and are trying to stem such destruction of forests.
The following are a handful of examples of medicines derived from trees and shrubs:
Quinine was the first effective treatment for malaria and remained the antimalarial drug of choice until the 1940s when it was chemically synthesized. It is extracted from the bark of the Cinchona tree (Cinchona spp.) and is added to liquid before being taken. The slightly bitter taste of tonic (as in gin and tonic) is (or was) quinine.
Aspirin is made from the bark of a Willow tree (Salix spp) by extracting salicylic acid and producing a solid chemical salt. Aspirin has three major medicinal uses, namely as an analgesic i.e. a pain killer, as an antipyretic, i.e. to lower body temperature (fever) and as an anti-inflammatory agent (reduces swelling).
Reserpine is extracted from the root of the Serpent-Root tree (Rauvolfia serpentine) and is used for lowering blood pressure and as a tranquilliser. In India, it is also used as a treatment for snake bites.
Sangre De Drago
Sangre De Drago (in Spanish) or Blood of the Dragon (in English) is the bright red sap of the tree, 'Blood of the Dragon' (Croton lechleri). The sap is simply painted on wounds to stop bleeding and accelerate healing. It forms a second skin protecting the wound from infection but also accelerating the healing process in a dramatic manner. A veritable cure-all, it also appears to kill fungal infections and viruses as well.
Oil of Wintergreen
Oil of Wintergreen is distilled from the leaves and twigs of a number of trees and shrubs including the Black or Sweet Birch (Betula lenta) and Wintergreen (Gaultheria fragrantissima). It is and has been used to treat numerous ailments including; rheumatic pain, cold symptoms, colic, headaches, skin diseases, sore throats and tooth decay. However, its medicinal properties have not been clinically proven and due to its toxicity, it is no longer used internally for medicinal purposes.
Cocaine is extracted from the tips of the fresh new leaves produced by Coca plant (Erythroxylum coca), a shrub reaching up to 3.0m in height. It is used medicinally as a local anaesthetic, although it is best known and more widely used as a recreational drug for its stimulant properties.
Frankincense and myrrh
Frankincense and myrrh are the sap or resin from the small trees/shrubs of the same names (Boswellia caraterii and Commiphora myrrha respectively). In Chinese medicine, the resins are classified as herbs and used for treating a variety of complaints including; poor circulation of the blood, traumatic injury, painful swellings and other disorders related to stasis syndromes e.g. deep vein thrombosis.
Taxol is extracted from the inner bark of the Pacific Yew (Taxus brevifolia) and has been demonstrated to be very effective in the treatment of both breast and ovarian cancer.
A Word of Caution
The extracted compounds of some trees and shrubs, for example, Taxol, have proven medicinal benefits. However, there are two sides to the coin and the flip side is that some parts of flowering plants are toxic to varying degrees, when ingested in their natural state, including:
- Yew (Taxus spp). All parts of the plant, except for the fleshy red bit of the fruit, contain taxane alkaloids. The seeds are especially poisonous and can be quickly fatal when ingested.
- Elderberry (Sambucus nigra). The roots are poisonous and cause nausea and digestive upset.
- Common Holly (Ilex aquifolium). The berries are poisonous, causing gastroenteritis.
- Oak (Quercus spp). Most species foliage and acorns are mildly poisonous, causing digestive upset, heart trouble and contact dermatitis. Seldom fatal.