Comparison of Kinetic Study and Protective Effects of Biological Dipeptide and Two Porphyrin Derivatives on Metal Cytotoxicity Toward Human Lymphocytes

In this research, dipeptide (his-β-alanine) and porphyrin derivatives were choosen for comparing chelating ability of toxic metals such as Al(3+), Cu(2+), Hg(2+) and Pb(2)(+ )in-vitro. The reason for choosing these two compounds is that both of them are naturally present in biological systems and comparison of chelating ability of these two compounds has not yet been done. Synthesis and comparison of kinetic study of dipeptide (his-β-alanine), meso-tetrakis(4-trimethylanilinium) porphyrin (TAPP) and Tetrakis(4-sulfonatophenyl)porphyrin (TPPS(4)) were carried out by our team. In addition, cytotoxicity assays of metals and chelators were also performed using methylthiazoletetrazolium (MTT) test. Furthermore we investigated the protective effect of chelators against cytotoxicity, induced by differenrt toxic metals such as Al(3+), Cu(2+), Hg(2+) and Pb(2+ )on human lymphocytes. EC(50) values on human lymphocytes obtained after 12 h. incubation for Al(3+), Cu(2+) and Hg(2+ )were 30, 51, 3 µM respectively and for Pb(2+) no cytotoxicity was observed on human lymphocyte up to 1000 µM concentration. EC(50) obtained for chelators dipeptide, TPPS(4) and TAPP were 948, 472 and 175 µM respectively. Pretreatment of human lymphocyte with subtoxic concentations of chelators reduced toxicity of the metals against human blood lymphocytes.