Although extracts, such as essential oils, have been prepared from various plants for centuries, traditional herbalist has always combined herbs to modify effects, viewing the whole as greater than the parts. The move to identify the individual active ingredients and use these as single drugs began in the 18th century, and many thousands are now known. These chemicals display quite different properties from the original herbs. Initially, these drugs could only be obtained from plant extracts but later the chemical structures of many extracts were identified and the drugs are now made synthetically.
In the transition from the use of crude plants to clinical pills, modern medicine has lost the art of combining herbs to modify toxicity and of using whole plants, which themselves contain chemical ingredients that can reduce the risk of side effects.
DRUGS FROM PLANTS
One of the first modern drugs to be isolated from a plant was morphine, first identified in 1803 by Friedrich Senurner in Germany. He extracted white crystals from crude opium poppy. Similar techniques soon produced aconite from monkshood, emetine from ipecacuanha, atropine from deadly nightshade, and quinine from Peruvian bark.
All of these compounds, categorized as alkaloids, are extremely potent and could only be obtained from the raw plants until scientists were able to synthesize them.
The breakthrough came in 1852 when Salicin, identified as one of the active ingredients in willow bark, was artificially synthesized for the first time. This was later modified to be less of an irritant on the stomach, and acetylsalicyhc acid was launched as aspirin, in 1899, by the drug company Bayer. In less than 100 years, plant extracts have filled pharmacists’ shelves. There are many preparations from ma huang, for example, both prescription and over-the-counter, which are mainly used for coughs phlegm, hay fever, or asthma. Pilocarpine, obtained from jaborandi, is used for treating glaucoma; vincrisrine, from the Madagascar periwinkle, is used for leukemia; while strophanthin from Strophanthus kombe (found in tropical Africa and used to tip poison arrows) is taken for severe heart problems.
Extracted chemicals can often be extremely potent and can cause effects that were unknown when the whole plant was used. Indian snakeroot, Rauwolfia Serpentina, for example, has been used for centuries in Ayurvedic medicine for a range of ailments including snakebites, anxiety, headaches, fevers, and abdominal pains. Mahatma Gandhi reputedly drank snakeroot tea at night if he felt over-stimulated. In the West, snakeroot was valued as a potent tranquilizer and was used for high blood pressure; it was also prescribed in the treatment of schizophrenia and psychosis.
In 1947, CIBA extracted the alkaloid reserpine from snakeroot and began marketing the drug Serpasil as a cure for hypertension. However, resperine has unfortunate side effects that include severe depression and abnormal slowing of the heartbeat. A new tranquilizer drug was developed from the herb in the 1950s. It has always been restricted to the status of prescription-only in the United States. To this day, however, snakeroot continues to be widely used in other parts of Europe and Asia, taken by many as a soothing tranquilizer.