New thiosemicarbazones: synthesis, structural characterization, in vitro, and in silico evaluation of antiproliferative effects.

Aims: To design, synthesize, and characterize N-(4-bromophenyl)-2-(substituted fluorobenzylidene)hydrazine-1-carbothioamides (II-IV) and evaluate their in vitro cytotoxicity against DLD-1 and MDA-MB-231 cells, supported by molecular docking.

Materials & methods: Compounds were obtained by condensations of substituted fluorobenzaldehydes with N-(4-bromophenyl)hydrazinecarbothioamide and characterized by NMR, FTIR, and MS. DLD-1 and MDA-MB-231 cells were exposed to 50-1600 µg/mL for 24 h; viability was measured using a commercial colorimetric assay. Statistics used one-way ANOVA with post hoc tests. Blind docking was performed with CB-Dock2 and interactions inspected in Discovery Studio.

Results: All compounds decreased viability in a concentration-dependent manner. In MDA-MB-231, Compounds I, II, and IV showed significant effects (ANOVA p < 0.001). In DLD-1, Compound IV reached p ≤ 0.01 and Compounds I-II p < 0.001; the IC₅₀ of Compound I in DLD-1 was 1383.2 µg/mL. Docking suggested favorable binding poses stabilized by hydrogen bonding and hydrophobic/halogen interactions at key residues.

Conclusions: The 4-bromophenyl thiosemicarbazone/Schiff-base scaffold exhibits measurable antiproliferative activity with substitution-dependent trends supported by docking. These findings warrant structure optimization to enhance potency and selectivity and motivate follow-up mechanistic assays. (Not a clinical trial; CONSORT not applicable.).