Synthesis, crystal structure, cytotoxicity (MCF-7 and HeLa) and free radical scavenging activity of the hydrazones derived from 2-methylsulfonyl-5-nitrobenzaldehyde

The rising levels of breast and cervical cancers among women have become public health problem with high economic burden globally and more especially in low- and middle-income countries. This necessitates discoving new and potent anticancer drugs with reduced or no side effects. The hydrazones derived from 2-formyl-4-nitrophenyl methanesulfonate were characterized using a combination of spectroscopic and single-crystal X-ray diffraction (XRD) techniques. The compounds were, in turn, evaluated for antigrowth effect in vitro against the human breast adenocarcinoma (MCF-7) and human cervical cancer (HeLa) cell lines and for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The presence of a chlorine atom on the para position of the phenylhydrazone moiety of 3b resulted in increased cytotoxicity against the MCF-7 and the HeLa cell lines compared to camptothecin (IC₅₀ = 9.15 ± 0.84 µM and 3.71 ± 0.16 µM, respectively) with IC₅₀ values of 5.64 ± 0.84 µM and 2.40 ± 0.13 µM, respectively. Compounds 2, 3a and 3b were found to exhibit significantly reduced toxicity against the Vero cells compared to the anti-cancer drugs, doxorubicin (IC₅₀ = 0.78 ± 0.04 µM) and nintedanib (IC₅₀ = 0.24 ± 0.02 µM) with the IC₅₀ values of 17.86 ± 1.12, 11.89 ± 1.01 and 24.42 ± 0.70 µM, respectively. The hydrazones 3a and 3b exhibited a strong inhibitory effect against the vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase (IC₅₀ = 5.78 ± 0.039 μM and 5.79 ± 0.053 µM, respectively) compared to the carbaldehyde precursor 2 (IC₅₀ = 8.01 ± 0.052 µM) though less active compared to nintedanib (IC₅₀ = 1.05 ± 0.193 µM). The hydrazone derivatives exhibited significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity compared to ascorbic acid and the parent 2-formyl-4-nitrophenylmethanesulfonate. In silico molecular docking studies revealed the binding potential of the hydrazones at the active site of VEGFR-2 tyrosine kinase and cytochrome c peroxidase.