DNA Interaction Study of Some Symmetrical 1,2-Phenylenediamine Schiff’s Base Derivatives as New Potential DNA Intercalators Using Ethidium Bromide Competition Fluorescent Assay

Abstract

Several biological experiments proposed that DNA is one of the principal cellular targets for numerous anticancer agents. Mainly, in cancer cells, DNA could be selectively damaged, as a result of interactions with anticancer agents, consequently blocking of cell division leads to cell death [1,2]. The molecules that interact with DNA are generally bound to DNA through non-covalent bonds by three main mechanisms: groove binding, intercalation or static electronic interactions. Static electronic interactions could be related to molecules that bind to the negatively charged DNA double helix at external sites through non-specific interaction. The second mode of interaction is called groove binding in which the targeting molecules interact with DNA in base edges of minor or major grooves [3][4][5][6]. The third mode of interaction is intercalation that is closely related to the antitumor ability of several anticancer drugs [7][8][9].Intercalators are ligands interacting with the DNA double helix in a reversible manner. Many of them are currently used as powerful drugs for the treatment of breast and ovarian cancers, acute leukemia, and many others are still in clinical trials. Intercalating agents have several universal structural features, the most important is a planar polyaromatic system that inserts between DNA base-pairs with a marked preference for the purine-3'-pyrimidine-5' sequence [10][11][12]. Ethidium bromide is frequently utilized as a fluorescent tag (nucleic acid stain) in molecular biology for many procedures such as agarose gel electrophoresis. It intercalates with double-stranded DNA and leads to the deformation of the DNA which could affect biological processes, such as DNA transcription and replication [13,14]. Schiff's bases (imines) are compounds that contain azomethine groups [-HC=N-] in their structure. They are formed