Some Azo Dyes Containing Uracil: DFT Study and Antiparasitic Activity for Leishmania promastigotes and Trichomonas vaginalis

Abstract

In this study 6-aminopyrimidine-2,4,5(3)-trione-5-[(phenyl)hydrazone] (dye 1) and 6-aminopyrimidine-2,4,5(3)-trione-5-[(4-methoxyphenyl)hydrazone] (dye 2) were resynthesized by method given in the literature and confirmed structurally using Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (H-1 NMR) spectroscopic methods. For the first time, for dyes 1 and 2, both theoretical studies were performed and investigated in terms of antiparasitic activity. The density functional theory (DFT) calculations for possible tautomeric forms of dyes 1 and 2 were carried out by using DFT/B3LYP/6-311++G (d,p) method. Thus, optimized geometries, IR and H-1 NMR spectral data were obtained and compared with experimental ones. Therefore, the most possible tautomeric forms were determined for dyes 1 and 2. Results show that in the gas phase and dimethyl sulfoxide (DMSO) solvent for both dyes, the amine-diketo-hydrazone forms (T-I-H) are the lowest energy and therefore the most stable form. Leishmania spp. and Trichomonas vaginalis are flagellated protozoan parasites that cause parasitic infections in humans. In vitro antiparasitic activity of dye 1 and dye 2 against Trichomonas vaginalis trophozoites, Leishmania tropica, Leishmania major, and Leishmania infantum promastigotes were determined for the first time. The in vitro antileishmanial and antitrichomonal activity was performed by microdilution method. Amphotericin B and Metronidazole were used for Leishmania spp. promastigotes, and T. vaginalis trophozoites, as a control drug, respectively. The Minimum Lethal Concentration (MLC) was determined and compared with the control.