Roles of metals in human health

Abstract

Metal ions are required to keep the human body healthy because several critical biological functions in humans depend upon their presence, and their absence or scarcity may lead to diseases. However, a few metal ions, particularly the so called heavy metal ions, such as mercury and lead, can be dangerous due to their toxic effects. Essential metal ions can also be toxic if present in excess, but their presence is crucial for survival. Among the metals that are currently known to be essential for normal biological functions in humans are sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca) that belong to main group of elements, and vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), and cadmium (Cd) that belong to transition metal group of elements in periodic table. Among these metals, the most notable that usually exist in the form of ions, are Fe, Co, Ni, Ca, Cu, Zn, and Cr. The deficiency of Fe and Co leads to anemia, that of Cu leads to brain and heart diseases and anemia, that of Zn leads to growth retardation and skin changes, that of Ca leads to bone deterioration, and that of Cr reduces the glucose tolerance.1‒5 Thus, now-a-days, the important aspect of medicinal bioinorganic chemistry is related to study at the molecular level the diseases caused by the deficiency or excess of the various metal ions and to find their remedy. The most important aspect of metal ions is their use in drug discovery. The drug industry has not relied only on essential metal ions but also on other metals. Two most important drugs, cisplatin (1) and auranofin (2), are widely used for the treatment of genitourinary and head and neck tumors, respectively. Metals ions also play essential roles in a variety of enzymes and control enzyme-catalyzed reactions by modifying electron flow in substrates or enzymes.6 Without appropriate metal ion, a biochemical reaction catalyzed by a particular metalloenzyme may proceed very slow. Metals can serve to bind and orient substrate with respect to functional groups in the active site. Now we present here in brief some description of drugs that contain metals and also the enzymes that essentially require metals.