Synthesis, Characterization, and Cytotoxic Activity Properties of Some Novel Purine Derivatives

This study reports the synthesis of nine new compounds with purine scaffolds. It thoroughly analyzes them using a variety of spectroscopic methods, including high-resolution mass spectrometry (HR-MS), proton nuclear magnetic resonance (¹H NMR), attached proton test nuclear magnetic resonance (¹³C APT NMR), and fourier-transform infrared spectroscopy (FT-IR). The in vitro cytotoxic potential of these compounds was examined using two cancer cell lines: MDA-MB-231, a model of triple-negative breast cancer, and HepG2, a model of liver carcinoma. Furthermore, compounds were tested in a normal mouse fibroblast cell line (L929). Biological screening revealed that two of the synthesized molecules, ethyl 2-(2-(2-(9H-purin-6-yl)hydrazineylidene)-3-(4-methylphenyl)-4-oxothiazolidin-5-ylidene)acetate (4b) and ethyl 2-(2-(2-(9H-purin-6-yl)hydrazineylidene)-3-(4-nitrophenyl)-4-oxothiazolidin-5-ylidene)acetate (4c) exerted cytotoxic effects with IC₅₀ values of 137.10 ± 6.46 and 130.70 ± 5.81 µM against the HepG2 cell line, respectively. At the same time, seven compounds (2b, 3a, 3b, 3c, 4a, 4b, and 4c) exhibited cytotoxic activity against MDA-MB-231 cells with IC₅₀ values of 197.40 ± 5.84, 161.90 ± 4.17, 66.33 ± 2.53, 122.10 ± 3.87, 159.80 ± 4.92, 138.10 ± 3.75, and 131.50 ± 2.46 µM, respectively. Caspase-3 activity assays were performed on the MDA-MB-231 cell line, which exhibited activity, and fluorescence imaging studies were also conducted. To elucidate potential molecular targets, in silico docking analyses were performed, indicating 15-lipoxygenase (15-LOX) as a likely enzymatic target. Among the evaluated molecules, compound 4b demonstrated superior binding affinity toward 15-LOX, even exceeding that of the co-crystallized reference inhibitor. The stability of the 4b-enzyme complex was further supported by molecular dynamics (MD) simulations, which showed an improved interaction profile compared to the original inhibitor-enzyme complex.