5 - Acute and Subacute Toxicities of African Medicinal Plants

Abstract

Medicinal plants are used worldwide as an alternative and/or a complementary medicine. Studies on these medicinal plants including pharmacological and toxicological evaluations are essential for drug research and development. The main types of toxicological evaluations include: acute toxicity, subacute toxicity, subchronic toxicity, and chronic toxicity studies. Medicinal plants also can be poisonous, affecting the entire spectrum of organ systems, with some plants containing several toxic principles that affect different systems. Toxic principles can be found in different parts of medicinal plants: leaves, fruits, flowers, roots, and stem bark. In evaluating the acute toxicity or subacute toxicity of medicinal plants, any animal species can be used, though rodents are used most often. Many African plants have undergone toxicity screening in the past three decades. In this chapter, we review more than 50 plants used in African Traditional Medicine (ATM) for several purposes. The criteria of classification their toxicity profile also are summarized. It appears that, though most of the plants in ATM are safe, numbers of them are potentially toxic and caution should be taken when they are used for therapeutic purposes. Some of these plants include Ocimum gratissimum, Pteleopsis hylodendron, Annona senegalensis, Syzigium aromaticum, Murraya koenigii, Sacoglottis gabonensis, and Spathodea campanulata.