**3. Herbal medicine**

Herbal medicine is a part and parcel of and sometimes synonymous with African traditional medicine. It is the oldest and still the most widely used system of medicine in the world today. It is used in all societies and is common to all cultures. Herbal medicines, also called botanical medicines, vegetable medicines, or phytomedicines, as defined by World Health Organization (WHO) refers to herbs, herbal materials, herbal preparations, and finished herbal products that contain whole plants, parts of plants, or other plant materials, including leaves, bark, berries, flowers, and roots, and/or their extracts as active ingredients intended for human therapeutic use or for other benefits in humans and sometimes animals [10, 11].

Herbal medicine is a special and prominent form of traditional medicine, in which the traditional healer, in this case known as the herbalist, specializes in the use of herbs to treat various ailments. Their role is so remarkable since it arises from a thorough knowledge of the medicinal properties of indigenous plants and the pharmaceutical steps necessary in turning such plants into drugs such as the selection, compounding, dosage, efficacy, and toxicity. The use of herbal medicines appears to be universal in different cultures. However, the plants used for the same ailments and the modes of treatment may vary from place to place. The plants used for medicinal purposes are generally referred to as medicinal plants, i.e., any plant in which one or more of its organs/parts contain substances that can be used for therapeutic purposes, or in a more modern concept, the constituents can be used as precursors for the synthesis of drugs. For example, a number of plants have been used in traditional medicine for many years without scientific data to back up their efficacy. In this case, these plants, whole or parts, which have medicinal properties, are referred to as crude drugs of natural or biological origin. They may further be classified as "organized drugs," if such drugs are from plant parts with cellular structures such as leaf, bark, roots, etc., and "unorganized drugs," if they are obtained from acellular portions of plants such as gums, balsams, gels, oils, and exudates. Compared with modern allopathic medicine, herbal medicine is freely available and can easily be accessed by all [12, 13]. As a result, there is limited consultation with traditional healers because there is a fairly good knowledge of common curative herbs especially in the rural areas except in the case of treatment of chronic diseases [12]. Even where consultation is done, there is lack of coherence among traditional healers on the preparation procedures and correct dosage of herbal medicines [14]. However, according to WHO [15], at least 80% of people in Africa still rely on medicinal plants for their health care. In Nigeria, and indeed the entire West Africa, herbal medicine has continued to gain momentum, some of the advantages being low cost, affordability, availability, acceptability, and apparently low toxicity [16, 17].

A detail of plant parts used in herbal medicines is as follows:


In many areas of Africa, the knowledge of plant species used and the methods of preparing and administering the medication, especially for serious ailments, still reside with traditional healers. Secrecy and competition still surround the use of these medications, with the healers often being reluctant to hand down their knowledge to anyone but trusted relatives and initiates [18].

Herbal Medicines in African Traditional Medicine http://dx.doi.org/10.5772/intechopen.80348 195

Methods of preparation of herbal medicines may vary according to place and culture. The plant materials may be used fresh or dry. With experience, a particular method is chosen to increase efficiency and decrease toxicity. Generally, different methods of preparation include:

**1.** Extraction—This is prepared with solvent on a weight by volume basis. Sometimes, the

**2.** Infusions are prepared by macerating the crude drug for a short period of time in cold or

**3.** Decoctions are made by boiling woody pieces for a specified period of time and filtered.

hot water. A preservative such as honey may be added to prevent spoilage.

Potash may be added to aid extraction and as preservative.

**3.1. Methods of preparation and dosage forms**

**Figure 2.** Herbs on display (Source—Ancient Origins).

solvent is evaporated to a soft mass.


Sale of herbs in form of dried or fresh plant parts is as lucrative as the prepared medicines. They are usually displayed in markets and sold with instructions on how to prepare them for maximum efficacy.

**Figure 2** is a photograph of an herbalist displaying his herbs for sale.

**Figure 2.** Herbs on display (Source—Ancient Origins).

of drugs. For example, a number of plants have been used in traditional medicine for many years without scientific data to back up their efficacy. In this case, these plants, whole or parts, which have medicinal properties, are referred to as crude drugs of natural or biological origin. They may further be classified as "organized drugs," if such drugs are from plant parts with cellular structures such as leaf, bark, roots, etc., and "unorganized drugs," if they are obtained from acellular portions of plants such as gums, balsams, gels, oils, and exudates. Compared with modern allopathic medicine, herbal medicine is freely available and can easily be accessed by all [12, 13]. As a result, there is limited consultation with traditional healers because there is a fairly good knowledge of common curative herbs especially in the rural areas except in the case of treatment of chronic diseases [12]. Even where consultation is done, there is lack of coherence among traditional healers on the preparation procedures and correct dosage of herbal medicines [14]. However, according to WHO [15], at least 80% of people in Africa still rely on medicinal plants for their health care. In Nigeria, and indeed the entire West Africa, herbal medicine has continued to gain momentum, some of the advantages being

low cost, affordability, availability, acceptability, and apparently low toxicity [16, 17].

**1.** Roots—i.e., the fleshy or woody roots of many African plant species are medicinal. Most of the active ingredients are usually sequestered in the root bark rather than the woody

**2.** Bulbs—A bulb is an underground structure made up of numerous leaves of fleshy scales,

**3.** Rhizomes—Woody or fleshy underground stem that grows horizontally and brings out their leaves above the ground, e.g., *Zingiber officinale* (ginger), which is used for respiratory problems; *Imperata cylindrica* (spear grass) for potency in men and *Curcuma longa* (tur-

**4.** Tubers—Swollen fleshy underground structures which form from stems/roots, e.g., potatoes and yams such as *Dioscorea dumetorum (ona-(igbo))* for diabetes and *Gloriosa superba* for cancer.

**5.** Bark—The outer protective layer of the tree stem or trunk. It contains highly concentrated phytochemicals with profound medicinal properties. A host of plants have barks of high

**8.** Gums, exudates, and nectars, which are secreted by plants to deter insects and grazing animals and to seal off wounds, are very useful in the pharmaceutical industries.

Sale of herbs in form of dried or fresh plant parts is as lucrative as the prepared medicines. They are usually displayed in markets and sold with instructions on how to prepare them

A detail of plant parts used in herbal medicines is as follows:

e.g., *Allium sativa* (garlic) and *Allium cepa* (onions).

meric), an antioxidant, anti-inflammatory, and anticancer drug.

**6.** Leaves, stems, and flowers of many plants are also medicinal.

**7.** Fruits and seeds also contain highly active phytochemicals and essential oils.

**Figure 2** is a photograph of an herbalist displaying his herbs for sale.

inner part.

194 Herbal Medicine

medicinal value.

for maximum efficacy.

In many areas of Africa, the knowledge of plant species used and the methods of preparing and administering the medication, especially for serious ailments, still reside with traditional healers. Secrecy and competition still surround the use of these medications, with the healers often being reluctant to hand down their knowledge to anyone but trusted relatives and initiates [18].
