Original Article en9 Predicting Anti HIV Activity of Quinolone Carboxylic Acids – Computation Approach Using Topological Indices J. Senbagamalar 1 , J. Baskar Babujee 1 1 Department of Mathematics, Anna University, India Abstract Background: Quantitative structure–activity relationships (QSAR) are a major factor in contemporary drug design- ing. Thus, it is quite clear that a large number of users of QSAR are located in industrial research units. Objectives: A Topological Index is a numeric quantity that is mathematically derived in a direct and uambigu- ous manner from the structural graph of a molecule. In structure-activity relationship studies, molecular topology quantifies chemical structure into characteristic numerical descriptors. All structural formulas of chemical compounds are molecular graphs where vertices represent the set of atoms and edges represent chemical bonds. The construc- tion and investigation of topological indices that could be used to describe molecular structures is one of the im- portant directions of mathematical chemistry Topological descriptors developed for predicting physicochemical pro- perties and biological activities of chemical substances can be used for drug design. Matherials and Methods: A number of successful QSAR studies were made based on the Wiener index, Terminal Wiener Index and Platt Number. These indices are derived from matrices, like distance matrix and adjacency matrix which represents a molecular graph. Zagreb Index is based on degree connectivity indices. Results and Conclusion: In this paper we analyze, Quan- titative structure activity relationship studies were per- formed on anti- HIV activity of Quinolone carboxylic acid for Wiener Index, Terminal Wiener Index, Platt Number and Zagreb Index. Keywords Graph, vertices, wiener index, degree, atom, quinolone car- boxylic acid Correspondence to: J. Senbagamalar Department of Mathematics, Anna University Address: Chennai – 600 025, India E–mail: senbagamalar2005@yahoo.com EJBI 2013; 9(2):9–13 received: January 9, 2013 accepted: March 18, 2013 published: August 30, 2013 1 Introduction The discovery of the human immunodeficiency virus (HIV) as the causative agent of AIDS has led to enor- mous efforts to unravel the basic action of the virus at a molecular level. From this effort, a variety of targets for potential intervention of HIV multiplication have been identified. Anti-HIV therapy, today, is in need of new drugs, which are less toxic, active against the drug re- sistant mutants selected by current therapies in the viral replicative cycle. In the last decade, synthetic chemists have done tremendous research efforts for the development of newer anti-HIV agents [3]. Structure-based design, spurred by the significant pitfalls of the traditional method and the rapid advances in molecular-structure determination and computational resources, has now been accepted as a ra- tional approach for the generation of new pharmaceuti- cals. The successful implementation of quantitative struc- ture–property/activity relationship (QSPR/QSAR) cer- tainly decreases the number of compounds synthesized, by making it possible to select most promising compounds. Non empirical parameters of chemical structure derived from graph theoretic formalism are being used more fre- quently by many researchers in QSAR studies pertaining to molecular design, pharmaceutical drug-design, and en- vironmental hazard assessment of chemicals. In chemistry, a graph represents the topology of a molecule in the sense that it depicts the pattern of connectedness of atoms in the molecule, being at the same time, independent of such metric aspects of molecular structure as equilibrium dis- tance between nuclei, bond angles, etc. When a single number represents a graph invariant, it is known as topo- logical index or topological descriptor. These indices are derived from matrices, like distance matrix and adjacency matrix, which represent a molecular graph. Though nu- merous topological descriptors have been reported in the literature but only handful of them has been successfully c 2013 EuroMISE s.r.o. EJBI – Volume 9 (2013), Issue 2