Synthesis, Characterization, in vitro Antifungal Activities and Calf Thymus DNA Interactions of Two Different Hydroxy Benzaldehyde Derivative Schiff Bases from Sulfamethizole: Electrochemical, Spectroscopic and Biological Study

Abstract

In the present work, the Schiff bases were synthesized by reacting sulfamethizole (SMTZ) with two different hydroxy benzaldehydes (2,3-dihydroxy benzaldehyde (DHBA) and 2,4,6-trihydroxy benzaldehyde (THBA)) and characterized by elemental analysis, ¹H-NMR and IR spectroscopies. From the obtained data, it was suggested that 4,6-dihydroxy salicylaldehyde reacted with both primary and secondary amine groups of SMTZ. The binding properties between the synthesized Schiff bases and calf thymus DNA (CT-DNA) at the physiological pH (7.4) was investigated by using cyclic voltammetry and UV-Vis spectroscopy techniques. The experimental results verify that the Schiff bases can bind to CT-DNA by electrostatic mode in 1 : 1 stoichiometry. Antifungal activities of the synthesized Schiff bases against Candida albicans ATCC 10231 were studied and their minimum inhibitory concentrations (MIC) were also determined. The MIC value of the Schiff base 1 synthesized from DHBA is smaller than that of the Schiff base 2 obtained from THBA. Although Schiff base 2 binds to CT-DNA with a higher affinity than Schiff base 1, it is less effective than Schiff base 1 against Candida albicans.