Nature's Pharmacy: Ancient Knowledge, Modern Medicine

Introduction

The efficacious benefits of some of nature's pharmacy have long been forgotten or even condemned. Such is the case with the yaupon holly and tobacco whose original use in native North America were often part of carefully prescribed ceremonial contexts, where proper behavior was considered as important to a positive outcome, as was the preparation and administration of the plant itself. Others such as foxglove (digitalis), opium poppy (morphine), and cinchona (quinine), have long been recognized as medicinal "superstars." And, while folk practices have long benefited from ginseng, aloe, and echinacea, such plants and their active constituents have only recently been acknowledged by western medical science. Many of these species are now endangered by threats to their native habitats just as the scientific understanding of their importance is emerging.

The plant kingdom has provided an endless source of medicinal plants first used in their crude form as herbal teas, syrups, infusions, ointments, liniments, and powders. With the development of chemistry and western medicine, the active substances of many species have been isolated and in some cases, duplicated in the form of synthetic drugs. Nevertheless, the synthetic preparation of some drugs is either unknown or economically impractical. For this reason, scientists continue to search for and test little known plants, and conserve those whose medicinal properties have become crucial in the fight against disease.

Use in History
Over 4,000 years ago, according to tradition, the Chinese emperor Chi'en Nung put together a book (herbal) of medicinal plants called Pen Tsao. It contained descriptions of more than 300 plants, several of which are still used in medicine. During the same era and later, the Sumerians recorded prescriptions on clay tablets, while the Egyptians recorded exotic plant ingredients in Ebers Papyrus. The Greeks and the Romans derived some of their herbal knowledge from these early civilizations. Their contributions are recorded in De Materia Medica by Dioscorides and the 37-volume natural history written by Pliny the Elder. Some of these earlier works are known to us through translations into Arabic by Rhazes and Avicenna. The knowledge of medicinal plants was further nurtured by monks in Europe who studied and grew medicinal plants and translated the Arabic works.

The first "licensed" apothecary shops opened in Baghdad in the 9th century. By the 13th century, London became a major trading center in herbs and spices. Much adulteration occurred in this trade, because proper standards and quality controls had not been established. Poorly identified plants and substitutes for true medicinal herbs were sold everywhere. In 1753, Carolus Linnaeus introduced the binomial system of plant nomenclature, which helped in the identification of plants. With the subsequent publication of pharmacopoeias, the method of identification and the standard of quality for each drug was clearly defined.

The present trend to replace crude plant drugs with their pure active principles started with the pioneering work in the 18th century of Karl Scheele, who isolated organic acids from plants. This achievement was followed by the isolation of morphine from opium by Fredrich Serturner and quinine from cinchona bark by Pierre Pelletier and Joseph Caventou. These and similar discoveries opened the door to the field of phytochemistry. Today a vast number of modern drugs are still derived from natural sources; approximately 25% of all prescriptions contain one or more active ingredients from plants.