Analysis of heavy metals concentration in Kano herbal preparations for major disease conditions

Abstract

The use of herbal medicines for treatment, management and prevention of different disease conditions has been as old as human history. These herbs usually contained some chemical substances which are considered as beneficial, while others were not. Study of the levels of some essential (Copper, Cadmium, Cobalt, Iron, Manganese, Nickel and zinc) and toxic (Cd and Pb) heavy metals content of herbal preparations sold in Kurmi market of Kano state, Nigeria was carried out. The aim of this study is to evaluate the levels of essential and toxic heavy metals in Kano herbal preparations used for commonly identified disease conditions. The samples were digested by wet digestion method with nitric acid and perchloric acids and analyzed using Flame Atomic Absorption Spectrometer (FAAS). The data obtained were statistically treated and the results presented as mean of three replicated. The range of mean concentrations of the essentials Cu, Co, Fe, Mn, Ni, Zn and toxic Cd, Pb heavy metals obtained were 4.94-10.03μg/g, 3.33-3.80μg/g, 163.04-350.95 μg/g, 57.57-65.05μg/g, 9.94-15.63μg/g,, 6.86-66.59 μg/g and 1.53-3.23μg/g, 3.75-35.24 μg/g respectively. The level of contamination of the herbal preparation with the toxic heavy metals indicated 100% of the samples analyzed contained cadmium above WHO permissible limits (0.3μg/g) specified for herbal medicine and 33% of the samples contained lead (Pb) above WHO permissible limits (10μg/g) specified for herbal medicine. The gross level of contamination of these herbal preparations with Pb and Cd metals could be associated to poor adherence to quality control requirements such as current/good manufacturing practice (CGMP) and effective surveillance/enforcement. There is need for commitment for immediate action by both the herbal medicine practitioners and the relevant stakeholders in order to avert impending health hazards due to the tendency of gradual accumulation of these toxic metals in the body system of the consumers of these herbal preparations in order to attain to safe and effective herbal medicine usage in Nigeria.

Keywords: Disease conditions, Heavy metals, Herbal preparations, Kano