3-Imino derivative-sulfahydantoins: Synthesis, in vitro antibacterial and cytotoxic activities and their DNA interactions

Sulfahydantoins are five-membered rings found in the structure of chemicals that exhibit antibacterial, anti-inflammatory, and anticonvulsant properties. They also activate serine protease enzymes that catalyze the hydrolysis of peptide bonds. Five 3-imino sulfahydantoin compounds were synthesized by using Strecker synthesis reaction with minor modifications. We used reflux of various aldehydes with excess sulfamide in 85% methanol in the presence of sodium cyanide. The spectroscopic properties of these compounds were studied in detail. Antibacterial activities of all synthesized new compounds against four Gram-positive (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Streptococcus mutans) and four Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella Enteritidis) bacteria were investigated by disc diffusion and microdilution method. pBR322 plasmid DNA binding abilities of compounds were investigated in vitro by agarose gel electrophoresis. In addition, the cytotoxic activities of the compounds against the human malignant pleural mesothelioma (SPC212) cell line were determined by the MTT method. The remarkable result in this study is that the synthesized compounds, especially 4b, 4d, and 4e, have significant biological activities. It has been demonstrated that these compounds, which cause DNA damage, also have an important antibacterial effect on both Gram-negative and Gram-positive bacteria when results compared with the control group antibiotics. Compound 4e exhibited the highest antibacterial potency against Streptococcus mutans (24.33 ± 0.57) from Gram-positive bacteria and Pseudomonas aeruginosa (24.66 ± 1.15) from Gram-negative bacteria. At the same time, MTT results determined that compounds 4b, 4d, and 4e showed cytotoxic activity against the SPC212 cells. In particular, compound 4b had a high cytotoxic effect, and the IC₅₀ value was determined as 6.25 µM.

In vitro cytogenetic activity of 3-amino-4-[4-(dimethylamino)phenyl]-4,5-dihydro-1,2,5-thiadiazole 1,1-dioxide

In a previous study, 3-amino-4-[4-(dimethylamino)phenyl]-4,5-dihydro-1,2,5-thiadiazole 1,1-dioxide (DPTD), which is five-membered cyclosulfamide, was synthesized and structurally characterized. The aim of this study was to investigate the cytotoxic and genotoxic effects of DPTD on cultured human lymphocytes in the presence and absence of a metabolic activation system (S9 mix). The cytotoxicity and genotoxicity of DPTD in human peripheral blood lymphocytes were examined in vitro by using chromosomal aberration (CA) and micronucleus (MN) tests. Mitomycin-C (MMC) for cultures without S9 mix and cyclophosphamide monohydrate (CP) for cultures with S9 mix were used as positive controls. The cultures were treated with DPTD (45, 90, and 180 µg/mL) in the absence and presence of S9 mix. The cells were also co-treated with DPTD together with MMC or CP. DPTD showed cytotoxic activity due to decreases in mitotic index (MI) and nuclear division index (NDI) in the absence and presence of S9 mix. DPTD also increased the CAs, aberrant cells with CAs and MN values in cultures with and without S9 mix. When DPTD and MMC or CP were used together, lower MI and NDI values and higher CA and MN values were found than those DPTD treated alone. Both DPTD and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Furthermore, co-treatment of DPTD and MMC or CP can cause more cytotoxicity and genotoxicity. Our results indicated that the use of DPTD with other chemotherapeutic drugs may display more effective results.

The new Schiff base 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one: experimental, DFT calculational studies and in vitro antimicrobial activity

The synthesized Schiff base, 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (I), has been characterized by (13)C NMR, (1)H NMR, 2D NMR ((1)H-(1)H COSY and (13)C APT), FT-IR, UV-vis and X-ray single-crystal techniques. Molecular geometry of the compound I in the ground state, vibrational frequencies and chemical shift values have been calculated by using the density functional method (DFT) with 6-311++G(d,p) basis set. The obtained results indicate that optimized geometry can well reflect the crystal structural parameters. The differences between experimental and calculated results of FT-IR and NMR have supported the existence of intermolecular (O-H⋯O type) and intramolecular (C-H⋯O type) hydrogen bonds in the crystal structure. Molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and electronic absorption spectra were carried out at B3LYP/6-311G++(d,p). HOMO-LUMO electronic transition of 3.92eV is due to contribution of the bands the n→π∗. The antimicrobial activity of the compound I was determined against the selected 11 bacteria and 8 fungi by microdilution broth assay with Alamar Blue. In vitro studies showed that the compound I has no antifungal effect for selected fungal isolates. However, the compound I shows remarkable antibacterial effect for the bacteria; Streptococcus pneumoniae, Haemophilus influenzae and Enterococcus faecalis.

3-Amino-4-[4-(dimethyl-amino)-phen-yl]-4,5-dihydro-1,2,5-thia-diazole 1,1-dioxide

The title compound, C(10)H(14)N(4)O(2)S, exists in the amine tautomeric form. The dihedral angle between the benzene and thia-diazo-lidine rings is 66.54 (19)°. In the crystal, mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds into a layer parallel to the ac plane. The layers are further linked by C-H⋯O hydrogen bonds.