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    Structural analysis and biological functionalities of iron(III)- and manganese(III)-thiosemicarbazone complexes: in vitro anti-proliferative activity on human cancer cells, DNA binding and cleavage studies
    (Springer, 2019) Kaya, Busra; Yilmaz, Zehra Kubra; Sahin, Onur; Aslim, Belma; Tukenmez, Ummugulsum; Ulkuseven, Bahri
    One iron(III) and two manganese(III) complexes based on thiosemicarbazone were synthesized and characterized using analytical and spectroscopic data. The crystallographic analysis showed the square pyramid structures of the complexes. Electronic spectra analysis was performed to determine the nature of the interaction between the complexes and calf thymus DNA (CT-DNA). DNA cleavage activities of the complexes were examined by gel electrophoresis (pBR322 DNA). The cytotoxicity of the complexes was determined against human cervical carcinoma (HeLa) and human colorectal adenocarcinoma (HT-29) cell lines by MTT assay. The results indicated that complex Fe1 is bound to CT-DNA via the intercalation mode, while complexes Mn1 and Mn2 are bound to CT-DNA via groove binding and/or electrostatic interactions rather than the intercalation mode. In addition, they showed good binding activity, which followed the order of Fe1>Mn2>Mn1. Complexes were found to promote the cleavage of DNA from supercoiled form (SC, Form I) to nicked circular form (NC, Form II) without concurrent formation of Form III, revealing the single-strand DNA cleavage. No significant cleavage was found in the presence of Mn1 and Mn2; however, it was observed at 2000 and 3000 mu M concentrations of Fe1. The ability of Fe1 to cleave DNA was greater than that of other complexes and these results are in conformity with their DNA-binding affinities. Cytotoxicity determination tests revealed that the complex Fe1 on HeLa and HT-29 cells exhibited a higher anti-proliferative effect than Mn1 and Mn2 (Fe1>Mn2>Mn1). These studies suggested that the complex Fe1 could be a good candidate as a chemotherapeutic drug targeting DNA. [GRAPHICS]
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    Öğe
    Structural characterization of new zinc(ii) complexes with N2O2 chelating thiosemicarbazidato ligands; investigation of the relationship between their DNA interaction and in vitro antiproliferative activity towards human cancer cells
    (Royal Soc Chemistry, 2020) Kaya, Busra; Yilmaz, Zehra Kubra; Sahin, Onur; Aslim, Belma; Ulkuseven, Bahri
    Two new zinc(ii) complexes were synthesized by condensation of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione-S-methyl-thiosemicarbazone with salicylaldehyde or 4-methoxy-salicylaldehyde. Structures of the N2O2-chelate complexes, Zn1 and Zn2, were explicated by IR, H-1 NMR, ESI-MS and X-ray crystallography. Electronic spectral analysis was performed to assign the nature of the interaction between the complexes and calf thymus DNA (CT-DNA). DNA cleavage activities of the complexes were investigated by gel electrophoresis (pBR322 DNA). The results indicated that the complexes bind to CT-DNA via an intercalation mode and the binding of Zn2 is stronger than that of Zn1. Relatively high concentrations of the zinc complexes were found to encourage the cleavage of DNA from supercoiled form (Form I) to nicked circular form (Form II). The antiproliferative activity of the complexes was determined against human colorectal adenocarcinoma (HT-29) and human cervical carcinoma (HeLa) cell lines by MTT assay. The tests revealed that the complex Zn2 exhibited a higher antiproliferative effect than Zn1 on HT-29 and HeLa cells, analogical to the data from DNA interaction experiments. The studies demonstrated that complex Zn2 could be a good candidate as a chemotherapeutic drug targeting DNA.