Novel Cinnamaldehyde Hydrazones: Design, In Silico Evaluation, Synthesis, and Cytotoxic Activity

(1) Background: Cinnamaldehyde exhibits a broad spectrum of biological activities, and its α,β-unsaturated aldehyde scaffold serves as a versatile platform for the design of hydrazone derivatives with improved pharmacological properties. (2) Methods: In this study, eight cinnamaldehyde-based hydrazones were synthesized via a one-step condensation reaction between cinnamaldehyde and para-substituted acylhydrazides. Prior to synthesis, an in silico assessment of physicochemical, pharmacokinetic, ADME (absorption, distribution, metabolism, elimination), lead-likeness, and drug-likeness properties was conducted using SwissADME, ACD/Labs v. 9.10, and MDL QSAR v2.2.0.0.446 software. Structural characterization by IR, ¹H NMR, ¹³C NMR, and HR ESI-MS confirmed successful formation of the hydrazone linkage. Cytotoxic activity was evaluated using the MTT assay against selected cancer cell lines. (3) Results: All compounds exhibited favorable lead-like characteristics, including suitable molecular weight, moderate lipophilicity, and acceptable predicted ADME profiles. Biological evaluation revealed moderate, structure-dependent antiproliferative activity with clear cell line selectivity. Among the series, compound CA8 showed the most promising profile, displaying the highest cytotoxic activity against T-cell leukemia KE-37 cells (IC₅₀ = 20.3 ± 2.8 μM), comparable to reference drug melphalan (IC₅₀ = 21.40 ± 3.9 μM), and the highest selectivity index (≥19.7). Structure-activity analysis suggests that an amino substituent enhances both potency and selectivity. (4) Conclusions: Overall, these findings identify cinnamaldehyde hydrazones as a promising scaffold for anticancer drug development and provide a strong basis for further structural optimization.