Syntheses of new derivatives of amino acids and peptides and studies of their radioprotective activity

The synthesis of ethyl esters of 2‐salicylidene derivatives of tyrosine, γ‐amino butyric acid (GABA), and glycyl‐glycine was carried out. These Schiff base ligands present themselves as pale‐yellow crystals. These Schiff bases have been used to prepare Mn (II) complexes by allowing them to react with Mn (II) ion. Their possible structures were determined using several analytical and physical‐chemical techniques. These Mn (II) complexes are obtained as gray crystals. Cytogenetic studies of bone marrow cells from whole‐body 4.2 Gy (0.42 Gy/min dose rate) irradiated white inbred rats revealed that prior administration of 10mg/kg of the Mn chelate of the ethyl ester of the 2‐salicylidene derivative of tyrosine was radioprotective. Compared to two control groups: (I) — animals exposed to irradiation only and (II) — animals treated with vehicle before irradiation, there was a 7‐fold decrease in number of chromosome aberrations. Mn‐chelates of 2‐salicylidene GABA and glycyl‐glycine were less radioprotective. The studies compounds have just as superoxide scavanging activity.