*Corresponding Author Address: Ludmila S. Bobkova, Department of the synthesis of biologically active substances, SI “Institute of pharmacology and toxicology NAMS of Ukraine”, Kiev, Ukraine World Journal of Pharmaceutical Sciences ISSN (Print): 2321-3310; ISSN (Online): 2321-3086 Published by Atom and Cell Publishers © All Rights Reserved Available online at: http://www.wjpsonline.org/ Original Article Synthesis, antioxidant activity and QSAR studies of some pyridine derivatives Ludmila S. Bobkova, Andrew R. Khairulin, Anatoly M. Demchenko, Tatiana A. Bukhtiarova DОpartmОnt of tСО syntСОsis of bioloРiМally aМtivО substanМОs, SI “InstitutО of pСarmaМology and toxicology NAMS of UkrainО”, KiОv, Ukraine Received: 07-03-2015 / Revised: 25-03-2015 / Accepted: 09-04-2015 ABSTRACT New quaternary pyridine salts and bases was synthesized and characterized in the presence of iminomethyl- fragment containing the hydroxyl group or the hydroxy-ethyl group or the hydroxyphenyl group with imine nitrogen atom. The synthesized compounds were tested in vitro for an antioxidant activity with a stable radical 2.2-diphenyl-1-picrylhydrazyl and reactivation ability of Sarin-inhibited AChE. The influence of antioxidant activity parameters on reactivation ability and toxicity of the studied compounds was analyzed. Key words: pyridine derivative, antioxidant activity, reactivation ability, QSAR studies INTRODUCTION The overproduction of cell free radicals affects significantly on the development of many pathological states. Protection against its excess ensures the functioning of the cellular antioxidant system [1]. The appearance of cancer, arteriosclerosis, Alzheimer's disease is often associated whit the action of free radicals [9]. The antioxidant activity of natural and synthetic substances now is subject of very intensive studies and considered as their important description. This is evidenced by the large number of publications in the scientific periodical literature. This is due, in particular, with the fact that, as follows from the literature data, it is antioxidant properties are crucial in many aspects of the biological activity of substances [5]. Reducing the toxicity of drugs can be achieved through sharing with them the drugs of a class of antioxidants, because oxidative stress is accompanied by toxic effects of most xenobiotics [7]. For example, one of the mechanisms of toxicity of Adriamycin is a violation of pro - and antioxidant balance and oxidative stress [15]. Antioxidants display a wide spectrum of pharmacological activity and have anticancer, anti- inflammatory, and regenerating properties [3, 4]. For example, the antioxidant activity of Dibunole plays a role in the mechanism of its anti-cancer and local anti-inflammatory action [16]. Found that many drugs with antioxidant properties cause a pronounced anti-inflammatory effect. As a probable mechanism of anti-inflammatory and immunomodulatory effects may be assumed ability of drugs to regulate the processes of free-radical oxidation. It is known that Uracil and its derivatives are biologically active agents and are widely used in medicine. One of the most important properties of Uracil and its derivatives is their ability to slow down the radical-chain process. To the present time has been studied quite extensively reactivity of a number of Uracil derivatives in the reactions of chain breakage on peroxyl radicals [14]. By this time developed many different methods for determination of antioxidant activity in vitro [11]. Methods for determination of antioxidant activity of medicinal compounds using colored stable radicals, based on the determination of the reactivity of drugs by spectrophotometric method or by the EPR method. Usually use stable free radicals such as hydrazyl, nitroxyl, isolated in the free state [13]. To study the activity of natural antioxidants is commonly use the DPPH (2.2-diphenyl-1- picrylhydrazyl) [4]. PubMed database shows that