Medicinal Plants, Phytomedicines, and Phytotherapy
From a historical perspective, the production of medicines and the pharmacologic treatment of diseases began with the use of herbs. In fact, the very word drug used to denote a medicinal preparation is derived from the old Dutch word droog meaning“ to dry
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I 1 Medicinal Plants, Phytomedicines, and Phytotherapy not stated in the modern sense of disease entities but as symptoms. For example, cough, catarrh, and hoarseness were each considered separate illnesses. The monograph concluded with a detailed account of the various preparations that could be made from the herb. By and large, the authors of herbals were not laypersons but medical doctors trained in conventional medical schools. The herbals were written not just for doctors but also for the "common man:' in some cases for the express purpose of serving as a guide "when the doctor is too expensive or too far away" (quoted in Jiittner, 1983). Prior to 1800, when medicine entered the scientific age, traditional herbal medicine was the unquestioned foundation for all standard textbooks on pharmacology. It was not until the advent of modern chemistry and the development of modern pharmacotherapy and "medical science" that phytotherapy was relegated to the status of an alternative modality. From the historical perspective, however, it is incorrect to classify phytotherapy as a special or alternative branch of medicine. When we consider that the history of classical herbal medicine spans more than 2500 years from antiquity to modern times, it is reasonable to assume that many of the medicinal herbs used during that period not only have specific actions but are also free of hazardous side effects. Otherwise they would not have been passed down so faithfully through so many epochs and cultures. It would be frivolous and unscientific to dismiss the collective empirical experience of more than 50 generations of patients and physicians as simply a "placebo effect" (Benedum, 1998).
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Making Medicines Safer by Isolating and Modifying Plant Constituents
In his famous Account of the Foxglove [published in 1785, William Withering described how he was called to the home of an itinerant salesman in Yorkshire. "I found him vomiting incessantly, his vision was blurred, and his pulse rate was about 40 beats per minute. On questioning, I learned that his wife had boiled a handful of foxglove leaves in a half pint of water and had given him the brew, which he swallowed in one draught to seek relief from asthmatic complaints. This good woman was well acquainted with the medicine of her region but not with the dose, for her husband barely escaped with his life:' Cardiac glycosides of the digitalis type (from foxglove leaf, Digitalis purpurea and D. lanata) have a very narrow range of therapeutic dosages. Exceeding the full medicinal dose by just about 50 % can produce toxic effects. The dosage problem is compounded by the large qualitative and quantitative variations that occur in the crude plant material. Depending on its origin, the crude drug may contain a predominance of gitoxin, which is not very active when taken orally, or it may carry a high concentration of the very [orally?] active compound digitoxin. Thus, isolating the active constituents from herbs with a narrow therapeutic range (Fig. 1.1) and administering the pure c
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