28 | P age Heavy Metal Content of Selected Raw Medicinal Plant Materials: Implication for Patient Health P. Dzomba*, T. Chayamiti, E. Togarepi Chemistry Department , Faculty of Science, Bindura University of science education, P. Bag 1020, Bindura, Zimbabwe Email pdzomba@gmail.com or pdzomba@buse.ac.zw ABSTRACT The safety and quality of herbal medicines has become increasingly important for health authorities, scientific community and the public alike. Thus this study was aimed at determining the amount of heavy metals in selected raw traditional medicines. Heavy metal concentrations in these raw herbal drugs were found to be in the range of, 0.23-19.01 for Pb, 0.12- 0.39 for Cu, 0.25-1.30 for Zn, 0.01-0.14 for Ni,1.41-30.84 for Fe and 0.01-0.46 mg kg -1 for As. Heavy metal content that were found above permissible limits were: 19.01 for U. kirkiana bark and roots (Pb), U. kirkiana bark (12. 25 ± 0,01), roots (12.11 ± 0. 00) and O. americanum leaves (33.61.±0.07) and roots (30.84 ± 0.02) for iron. Significant difference was only noticed for each heavy metal among raw herbal drugs sampled from twenty one places for C. imberbe leaves and L. discolor roots (Pb) (ANOVA followed by least significant test at p = 0.05). Generally most of the drugs that are being used by people in Mashonaland central province were found to be toxic and unsafe for human consumption due to elevated levels of heavy metals especially Cu, Fe, As and Pb. It is suggested that pharmacovigilance must always be done to improve the quality, safety, and efficacy of herbal drugs. Every person dealing with plant medicine should be sensitized on how to maintain efficacy, quality and safety of such medicines. Keywords: raw herbal medicine, heavy metal content, patient health, safety. INTRODUCTION Traditional medicine use is increasing steadily due to increased cases of bacterial resistance to current pharmaceuticals, affordability and readily availability [1; 2]. About 70 – 80% of the world population continues to rely on non-conventional medicines which predominately consist of herbal sources in their primary health care [3]. Herbal medicines are likely to be contaminated with heavy metals [4; 5]. In trace amounts some heavy metals are essential for the human body however they maybe be toxic if present in a higher concentration [6; 7]. They have the ability to bioaccumulate and disrupt functions of vital organs and glands in the human body such as brain, kidney and liver [8]. Medicinal plants can be contaminated by heavy metals via roots uptake or by direct deposition of contaminants from the atmosphere onto plant surfaces. Lead is considered a potential carcinogen and is associated with pathology of many diseases which includes cardiovascular, kidney, blood, nervous, and bone diseases [9]. Lead is a protoplasmic poison with affinity for the grey matter of brains. It invades neurons, damages cells, nerve synapse and dendrites, and reduces the number of oxygen carrying red blood cells [10; 11]. It combines with phosphorous and enters the blood stream where it goes to the spleen, liver, and kidneys [10]. Excessive concentration of Zn and Cu in the body is of great concern because of their toxicity to humans and animals [12]. Arsenic and many of its compounds are potent poisons. It disrupts ATP product. Excess iron is stored in the liver, pancreas, pituitary, adrenals, heart, and skeletal muscles. When the body gets too much iron it leaches out of its storage sites and moves into the blood stream where it is taken to the brain [13]. Too much iron in the brain destroys neurons, leading to neurodegenerative diseases and neurological dysfunction, with Alzheimer‘s like symptoms [13]. Increasing use of traditional medicines is of special concern because they are not rigorously regulated thus the focus of this study was to determine the amount of toxic heavy metals in selected raw medicinal plant materials. The plants studded in this research include, Combretum imberbe, Lannea discolor, Ocimum americanum, Uapaca kirkiana, and Pseudolachnostylis maprouneifolia. These plants are widely used in many Southern African countries such as Zimbabwe, Zambia, Mozambique, South Africa, Namibia, Tanzania and Botswana as traditional medicines. Unfortunately there is limited knowledge about heavy metal safety of these herbs. Bulletin of Environment, Pharmacology and Life Sciences Online ISSN 2277 – 1808 Bull. Environ. Pharmacol. Life Sci.; Volume 1 [10] September 2012: 28 - 33 © All Rights Reserved Academy for Environment and Life Sciences, India Website: www.bepls.com Original Article