Herbalism

Herbalism is a traditional medicinal or folk medicine practice based on the use of plants and plant extracts. Herbalism is also known as botanical medicine, medical herbalism, herbal medicine, herbology, and phytotherapy. The scope of herbal medicine is sometimes extended to include fungal and bee products, as well as minerals, shells and certain animal parts.

Many plants synthesize substances that are useful to the maintenance of health in humans and other animals. These include aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Many are secondary metabolites, of which at least 12,000 have been isolated — a number estimated to be less than 10% of the total. In many cases, these substances (particularly the alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and spices used by humans to season food yield useful medicinal compounds.

In the written record, the study of herbs dates back over 5,000 years to the Sumerians, who described well-established medicinal uses for such plants as laurel, caraway, and thyme. Ancient Egyptian medicine of 1000 B.C. are known to have used garlic, opium, castor oil, coriander, mint, indigo, and other herbs for medicine and the Old Testament also mentions herb use and cultivation, including mandrake, vetch, caraway, wheat, barley, and rye.

Medical schools known as Bimaristan began to appear from the 9th century in the medieval Islamic world, which was generally more advanced than medieval Europe at the time. The Arabs venerated Greco-Roman culture and learning, and translated tens of thousands of texts into Arabic for further study. As a trading culture, the Arab travellers had access to plant material from distant places such as China and India. Herbals, medical texts and translations of the classics of antiquity filtered in from east and west.

Muslim botanists and Muslim physicians significantly expanded on the earlier knowledge of materia medica. For example, al-Dinawari described more than 637 plant drugs in the 9th century, and Ibn al-Baitar described more than 1,400 different plants, foods and drugs, over 300 of which were his own original discoveries, in the 13th century.

The experimental scientific method was introduced into the field of materia medica in the 13th century by the Andalusian-Arab botanist Abu al-Abbas al-Nabati, the teacher of Ibn al-Baitar. Al-Nabati introduced empirical techniques in the testing, description and identification of numerous materia medica, and he separated unverified reports from those supported by actual tests and observations. This allowed the study of materia medica to evolve into the science of pharmacology.

Avicenna's The Canon of Medicine (1025) is considered the first pharmacopoeia, and lists 800 tested drugs, plants and minerals. Book Two is devoted to a discussion of the healing properties of herbs, including nutmeg, senna, sandalwood, rhubarb, myrrh, cinammon, and rosewater. Baghdad was an important center for Arab herbalism, as was Al-Andalus between 800 and 1400. Abulcasis (936-1013) of Cordoba authored The Book of Simples, an important source for later European herbals, while Ibn al-Baitar (1197-1248) of Malaga authored the Corpus of Simples, the most complete Arab herbal which introduced 200 new healing herbs, including tamarind, aconite, and nux vomica. Other pharmacopoeia books include that written by Abu-Rayhan Biruni in the 11th century and Ibn Zuhr (Avenzoar) in the 12th century (and printed in 1491), The origins of clinical pharmacology also date back to the Middle Ages in Avicenna's The Canon of Medicine, Peter of Spain's Commentary on Isaac, and John of St Amand's Commentary on the Antedotary of Nicholas. In particular, the Canon introduced clinical trials, randomized controlled trials, and efficacy tests.