From: Trees of the World, An Illustrated Encyclopedia and Identifier
Although the bark and wood of trees is seldom edible, extracts from them have given rise to some of the world’s most important medicines. Malaria is said to have killed more people than all of the wars and plagues in history combined. Oliver Cromwell and Alexander the Great are two of the better-known people to have died at its hands. For centuries, the only known treatment was quinine, an alkaloid found in the bark of the evergreen cinchona tree, which grows in the tropical forests of Peru and Bolivia. Quinine was first used to treat malaria by the Quechua Indians and in the 16th Century the Spanish Conquistadores realized its potential. Called the “miracle cure” when it finally arrived in Europe, it was used to cure King Charles II, King Louis XIV and the Queen of Spain, among countless others. Quinine has been chemically reproduced since the 1940’s; however, in recent years some forms of malaria have developed resistance to synthetic quinine and the cinchona tree has once again become the center of attention.
If you have ever had a headache then the chances are that you will have reached for a bottle of aspirin, the world’s most widely used drug. Before aspirin came in bottles, aches and pains could be cured by walking to the nearest river and finding a piece of willow bark to chew on. Aspirin is a derivative of salicylic acid, which comes from the bark of the white willow, Salix alba. Nowadays aspirin is produced synthetically.
The last remaining member of a family that existed when dinosaurs roamed the earth, the maidenhair tree, Ginkgo biloba, has long been used for medicinal purposes. The leaves have traditionally been a staple of Chinese herbal medicine and used to treat everything from asthma to hemorrhoids. Now maidenhair tree leaves have found their way into western medicine and are used to treat memory loss and coronary conditions. Fluid extracted from the leaves helps to improve blood circulation. It relaxes blood vessels, enhancing blood flow throughout the body but in particular that going to the brain.
More than 2,000 different trees are currently used for medicinal purposes. Many, such as the Pacific yew, Taxus brevifolia, are helping in the fight against cancer. Castanospermum austral, the Australian Moreton Bay chestnut, contains an unusual alkaloid called castanospermine, which is able to help neutralize the Aids virus HIV. Witch hazel, Hamamelis virginiana, is a tree with strong antiseptic qualities. Native American tribes such as the Cherokee made a “tea” of the leaves, which they used to wash sores and wounds. Another important medicinal tree species is Eucalyptus globulus. Its leaves contain the oil cineol, which is very effective in the treatment of coughs, sore throats, bronchitis and asthma.
From Trees of the World, An Illustrated Encyclopedia and Identifier, by Tony Russell, Catherine Cutler and Martin Walters. Published by Anness Publishing Ltd., Britain, in 2007. ISBN #1-84681-187-2. Printed in China