Investigation and Determination the Binding Site of Glycyrrhizin of Liquorice to DNA

Glycyrrhizin(GL), is a triterpenoid saponin found in glychyrrhiza glabra (liquorice). This compound is a frequently used and very effective drug for the treatment of various malignancies. This study was designed to examine the interactions of glycyrrhizin with calf thymus DNA in aqueous solution at physiological conditions. FTIR spectroscopic method was used to determine the ligand binding modes, using constant DNA concentration (6.25mM) and various drug/DNA (phosphate) ratios of 1/240 to 1/1. UV-Vis spectroscopic method was used to determine the binding constants and the stability of glycyrrhizin-DNA and complexes in aqueous solution, using constant DNA concentration of 5.1×10-4 M and various glycyrrhizin concentrations of 5×10-6 - 1×10-4 M. Spectroscopic evidence showed that the interaction of glycyrrhizin with DNA occurred via G, A-T and PO2 group with binding constant of KGL-DNA = 5.7×103 M-1 and DNA remains in B-DNA conformation.