For thousands of years, plants have been used as medicine (Samuelson, 2004). They assumed crude forms of drugs in tinctures, teas, poultices, powders and other similar medicines (Balik and Cox, 1997; Samuelson, 2004). The plants used and the applications for particular diseases were oral texts passed down from one generation to the next. Eventually, this data will be collected in herbal pharmacopoeias (Balunas, 2005). Modern allopathic medicine has also evolved since ancient times and it is expected that many of the great and important new treatments of the future will be discovered and marketed using information from traditional knowledge and experience as their predecessors did. European traditions are particularly well-known and have greatly influenced modern Western pharmacognosy, but every society has well-established herbal traditions, some of which have rarely been studied. Thus, studying these traditions will not only shed light on the development of the field but also serve as a fascinating example of how creative our ability to adapt diverse cultural practices can be in developing new herbal traditions. In some countries medicinal plants are sometimes associated with supernatural powers and witchcraft because people are unable to see scientifically that plants can produce cures and predictions. The theory of signatures is one of such irrational ideas; its elements are found in most of the world's healing cultures (Boehm, 1982). It stipulates that plants - and these are considered signs of God on that plant - can indicate their curative properties. Red sap and juice indicate blood and menstrual problems; yellow flowers with bile and jaundice; the human shape of some roots with the female form of fertility, etc. The theory sometimes - but not always - works: Chelidonium majus has yellow flowers and a yellow alkaloid latex, and has been successfully used to treat jaundice (Guraib-Fakim, 2006).
Traditional African Medicine
Africa is the cradle of humanity and is home to the most ancient and possibly the most diverse of all medicinal systems. African country is marked by a very rich biological and cultural diversity and regional differences in healing practices. Yet today, sadly, systems of medicine are poorly recorded. The increasing need to document the medicinal uses of African plants arises because of the rapid destruction of the plants' natural habitats due to human activities. Reportedly, Africa has the highest rate of deforestation on earth. This loss is even more significant because the continent has a very high rate of endemism, with Madagascar topping the list at 82% (Green and Sussman, 1990). The various forms of African traditional medicine are holistic - involving both the body and the mind. Typically the healer will first establish the psychological basis of the illness and prescribe an appropriate remedy before prescribing medications to treat the symptoms of the condition. Well-known African medicinal plants are Acacia senegal (gum arabic), Agathosma betulina (buchu), Aloe ferox (Cape aloe), Aloe vera (North African native), Artemisia afra (African wormwood), Aspalanthus linearis (rooibos tea), Boswellia sacra (frankincense), Catha edulis (khat), Commiphora myrrha (myrrh), Harpagophytum procumbens (devil's claw), Hibiscus sabdariffa (hibiscus, roselle), Hypoxis hemerocallidea (African potato), Prunus africana (African cherry). Madagascar's contribution is Catharanthus roseus (pink periwinkle); there are many more to come as it diversifies the flora and fauna (Neumann et al., 2000; Neuwinger, 2000).Traditional American Medicine (North, Central and South)
North America:In the United States, as in many cultures, indigenous healers or shamans treated illness as a process of addressing both its physical and spiritual aspects. This shamanistic ritual process often involved chanting and dancing as well as other influences aimed at warding off evils so that the patient or the entire community could be cured (Fabrikant and Farnsworth, 2001). European settlers learned from local practices and adopted many of these herbal remedies, leading to the creation of the early United States Pharmacopeia. The best-known agents of healing in the United States are echinacea (Echinacea purpurea) and goldenseal (Hydrastis canadensis). Herbs or botanicals were viewed with suspicion for much of the 20th century and herbalism declined. Plants were regarded primarily as future sources of pure chemical compounds for drug manufacturing. However, in the past few years, the use of herbs and botanicals has been on the rise in the United States and Canada, although it is still considered a dietary supplement and not a remedy (Pieroni et al., 2000; Heinrich et al., 2004; Gurib-Fakim, 2006). Rich Central and South America: As Africa consists of various countries, so does Central and South America as they too have healing cultures that may well be termed less known and not well recorded. They will without a doubt yield the herbal medicines of the future. South America and Central America, partly due to their contribution to agriculture, have produced most of the world's food crops - from maize to potatoes and tomatoes, pumpkins, cassava, peanuts to sweet potatoes. Most of the traditional American Indian medicinal herbs are used, but the influence of Spanish, European, East Asian as well as African medical systems is noticeable on them. To give some notable examples of medicinal plants, one such example would include: Cinchona pubescens (Peruvian bark), Erythroxylum coca (coca), Ilex paraguariensis (mate), Myroxylon balsamum (tolu balsam), Paullinia cupana (guarana), Peumus boldus (boldo), Psidium guajava (guava), Spilanthes acmella (Brazilian cress), Tabebuia impetiginosa (lapcho) and Uncaria tomentosa (cat's claw) (Fabrikant and Farnsworth 2001; Gurib-Fakim 2006).
