Investigation of synthesis, characterization in vitro cytotoxic and genotoxic properties of new tripeptide substituted cyclotrifosphazenes

In this thesis, 2 dipeptide compounds (Boc-Tyr-Gly-OCH3 and Boc-Tyr-Ala-OCH3) were obtained by interacting the amino acid tyrosine (Boc-Tyr-OH) with Glycine and Alanine methyl ester hydrochloride forms with protected amine group and free carboxyl group respectively by CDMT method in acetonitrile medium. Using these dipeptides, Boc-Tyr-Gly-OH and Boc-Tyr-Ala-OH dipeptides were synthesized in the first step by converting the ester groups of the methyl ester dipeptide compounds into carboxyl groups in acetonitrile. Boc-Tyr-Gly/Ala-OH dipeptides were synthesized as Boc-Tyr-Gly-OH with Glycine (NH2-Gly-OCH3.HCl) and Alanine (NH2-Ala-OCH3.HCl), Boc-Tyr-Ala-OH dipeptide with Glycine (NH2-Gly-OCH3.HCl), Alanine (NH2-Ala-OCH3. HCl), Valine (NH2-Val-OCH3.HCl) and Phenylalanine (NH2-Phe-OCH3.HCl) methyl ester hydrochloride amino acids in acetonitrile using the CDMT method, 6 tripeptide compounds were obtained. In the third step, the obtained tripeptide compounds were interacted with the phosphazene starting compound DPP to obtain 6 disubstituted tripeptide-cyclotriphosphazene compounds. All the compounds obtained were followed by thin layer chromatography and purified by flash chromatography using the same mobile phase. Structural characterizations of the purified tripeptides were carried out by elemental analysis, FT-IR, 1H, 13C-APT NMR spectra and substituted phosphazene compounds were additionally characterized by 31P and HETCOR (2D) NMR and MALDI-TOF MS spectroscopy. Thermal properties of the compounds were determined by TGA method. From the TGA curves, the temperature at which almost all of the compounds start to decompose is above 400 0C. These results indicate that the obtained cyclotriphosphazenes are thermally stable. The cytotoxicity properties of the pure compounds against human cancer cell lines ovarian (A2780) and prostate (PC-3) cancer cell lines were determined by MTT assay method, % cell viability was determined and LogIC50 values of the compounds were calculated. Comet assay method was used to determine whether cell death was caused by DNA damage mechanism. It was determined by comet assay experiments that the decrease in cell viability was mainly due to DNA damage (p<0.05).