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 Al3+ , Cu2+ , Hg2+ and Pb2 + 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 (TPPS4 ) 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 Al3+ , Cu2+ , Hg2+ and Pb2+ on human lymphocytes. EC50 values on human lymphocytes obtained after 12 h. incubation for Al3+ , Cu2+ and Hg2+ were 30, 51, 3 µM respectively and for Pb2+ no cytotoxicity was observed on human lymphocyte up to 1000 µM concentration. EC50 obtained for chelators dipeptide, TPPS4 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.