(2E)-N-Methyl-2-[1-(4-methylcyclohex-3-en-1-yl)ethylidene]hydrazinecarbothioamide

Novel hydrazono-2-iminothiazolidin-4-ones based on a monoterpenic skelton as potential antitumor agents: Synthesis, DFT studies, in vitro cytotoxicity, apoptosis inducing properties and molecular docking

A new series of analogs-2-imino-4-thiazolidinone hybrid derivatives were synthesized by treatment of limonaketone-thiosemicarbazone derivatives with ethyl bromoacetate and dimethyl acetylene dicarboxylate (DMAD) as the cyclizing reagents. The new derivatives were characterized by HRMS, 1 H NMR and 13 C NMR spectroscopy techniques and one of them is characterized by single crystal X-ray diffraction. The newly synthesized products were biologically evaluated in vitro for their cytotoxic activity against three cancer cell lines including fibrosarcoma (HT-1080), lung carcinoma (A549), and breast carcinoma (MCF-7). Data showed that compounds 9 and 10 were the most active against HT-1080 cancer cell lines with the IC 50 values of 15.85±1.75 and16.13±1.55µM, respectively. The possible mechanism of apoptosis induction by the derivatives was investigated using Annexin V staining, caspase-3/7 activity and cell cycle analysis. Compound 10 was highly induced apoptosis through caspase-3/7 activation and S-phase arrest in HT-1080, while compound 9 showed a moderate induction of apoptosis through G0/G1-phase arrest in the same cell line. The molecular docking showed that compounds 9 and 10 activated the caspase-3 by forming a stable protein-ligand complex. Besides, the presence of phenyl moiety in ligand 10 is responsible for the enhancement of the caspase-3 activation by the apparition of two additional hydrogen bonds with Cys163 and Gln161amino acids.