The Analysis of the Electronic Structure of Linear and Cyclic Strcutures of GLY-PRO-PRO Trimer

In the human body, due to external agents such as air pollutants and UV radiations free radicals, reactive species (RS) and reactive oxygen species (ROS) acting as strong oxidants can be generated excessively and lead thereafter to diseases such as inflammatory diseases, cardiovascular dysfunctions, diabetes, cancer and many others [1,2]. Generally, antioxidants are used to reduce free radicals in the body. Antioxidants are man-made or natural compounds that inhibit the oxidation of other molecules that prevent reactive oxygen species (ROS) and free radicals construction [3-5]. Recently natural amino acids and their dendrimers (their di-decamers) were used as antioxidants and there are some publications on the structural modifications, such as cyclization that improve their antioxidant properties. Here, the geometrical and electronic structure as well as antioxidant activity of Gly-Pro-Pro (GPP) trimer in linear and cyclic configuration were investigated by the help of density functional theory. The results of the computations have been analyzed in order to derive the energy variations of changing of configuration from linear to cyclic for the considered systems. The all of computations have been carried out by GAMESS suit of computer codes in M06-X2 level of theory. The basis set of 6-31G were used for expantion of molecular orbitals. The results suggest that the considered trimer can be used as potential antioxidant material and can be considered as a candidate for future therpeutic agents for cancer.