**2. Methods**

168 Toxicity and Drug Testing

At present, work conducted on traditional medicine in Africa has mainly concentrated on the collection, identification, and classification of herbal products for treatment of different

Traditional medicines, like modern pharmaceuticals can do harm, but because humans have been using herbal drugs for long time, they are considered safe and non-toxic so the toxicological actions of these agents have been mostly ignored, even while the effectiveness is either already known or under study (O'Hara et al., 1998). Willcox (1999), carried out a clinical study on 'AM' (coded to protect the intellectual property right of the traditional healers), a popular antimalarial herb that has a long history of use among the people of south-western Uganda. In her result, 'AM' significantly reduced parasite count between day 1 and day 7, patients showed symptomatic improvement, but 50% of them experienced some side effects including vomiting, nausea and stomach upset. These were partly

If the origin of herbs' toxicity is not identified, the adverse effects may be wrongly associated with other environmental exposures or some traditional belief. Failure to establish the true cause of exposure also means that the patient continues taking the toxic herb. Thus, the screening of traditional remedies for safety and toxicity is recommended to protect public health. On the other hand, several plants used in Uganda traditional medicine can cause damage to genetic material and therefore have potential to cause long-term

**1.1 The main groups of active principle or constituents obtained from medicinal herbs**  The therapeutic effects of plant species are determined by their constituents. These affect the condition and function of the various human body organs, clear up residual symptoms or destroy the cause of the disease in most cases infectious micro-organisms. They help increase the body's resistance to disease, retard or delay the processes of natural aging or facilitate the adaptation of the organism to certain conditions (Forantisek, 2001). Over the centuries, man used medicinal plants even though he was unable to find a rational explanation for their effects. It was not until the 19th century and after the rapid development of organic chemistry and pharmacology, that man determined which active or group of principles are responsible for a given therapeutic effect. Knowledge of these substances frequently served as a model for the synthetic preparation of new medicines, enabling the drug to be modified and made more effective. It was soon discovered that a better therapeutic effect was often obtained by the particular combination of active principle naturally present in each plant that by a single, isolated substance. The most important constituents are the secondary metabolism in plants, which includes alkaloids, glycosides, essential oils, tannins and the bitter principles. Products of secondary metabolism of plants are responsible for the plants' therapeutics effects. Of greater importance for the plants themselves of course are the products of primary metabolism which are necessary for the proper function of the basic life processes in plants. Primary metabolism products are also used by man. This group includes sugars, fatty oils, organic acids, vitamins and protein. These products of primary metabolism themselves may have no therapeutic effect but may

damage in patients when administered as medicinal preparations (Steenkamp, 2005).

possibly increase the efficiency of the therapeutically important principles (70)

(Aseraceae), also called bitter leaf is a popular African vegetable that grows as a shrub or small tree indigenous to Central and East Africa including Uganda (Huffman et al, 1996). It

**1.2** *Vernonia amygdalina* 

ailments. However, research in the areas of safety and toxicology is lacking.

attributed to malaria itself as well as to 'AM' ingestion (Willcox, 1999).
