The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations.
The methanol extract of the stem bark of Anogeissus leiocarpus was evaluated in vivo at 2.5mg/kg for antioxidant, hepatoprotective and ameliorative effect on hepatocellular injury following pre-treatment or post-treatment with carbon tetrachloride (CCl4). Levels of the lipid peroxidation product, malondialdehyde (MDA) or thiobarbituric reactive substances (TBARS) were taken as a measure of oxidative stress, while levels of biochemical such as aspartate aminotransferase, alanine aminotransferase and bilirubin (total and conjugated) were taken as biomarkers of liver damage. Irrespective of whether the animals were preor posttreated with Anogeissus leiocarpus, there was no statistical difference between the levels of MDA and markers of liver damage in the groups on A. Leiocarpus + CCL4 group and Vitamin E + CCl4, although both were significantly (P<0.05) lower than in the group on CCL4 only. However, malondialdehyde (MDA) levels in the heart, and to some extent, in the kidney, were hardly influenced by the treatments. These results indicate that methanolic extract of the stem bark of Anogeissus leiocarpus possess antioxidant, hepatoprotective and ameliorative effect on hepatocellular injury which may in part, account for the mechanism by which this plant brings about some of its reported therapeutic effects. INTRODUCTION: According to Allen and Tresini (2000), reactive oxygen species (ROS) such as superoxyl, hydroxyl and peroxyl radicals are produced as part of normal metabolic processes and are believed to be involved in the oxidative damage of lipids, proteins, nucleic acids and other macromolecules. This causes different chronic diseases which among others include cancer, atherosclerosis, ageing, diabetes, asthma and cardiovascular disorders (Hadi et al., 2000). In developing countries of Africa where about 200,000 to 300,000 known plant species are found, and where about 85% of the population relies on traditional medicine as the cornerstone of their healthcare delivery, the United Nations encourages the inclusion of herbal medicine of proven safety and efficacy in their healthcare delivery program (UNESCO, 1998; Ampofo, (1997). Anogeissus leiocarpus is a plant that is widely used in Northern Nigeria ethnomedicine. It belongs to the phylum, Tracheophyta; Order; Myrtales and Family: Combretaceae (combretoideae). It is commonly called Axle-wood tree, and in Nigeria, it is referred to as Marke (Hausa), Kojoli (Fulani), Annum (Kanuri), Ayin or Orin-odan Ainy (Yoruba), Atara (Igbo) and Kukunchi (Nupe). It is a very graceful tropical tree which grows up to 28m and occurs in the most of the savannah