Spectroscopic, structural and anticancer activity studies of (−)-cytisine halogenated N-benzyl derivatives

(−)-Cytisine and its derivatives, characterized by high affinity to neuronal nicotinic acetylcholine receptors (nAChRs), have been shown to be important probes in the research of central nervous system disorders. In this work new halogenated N-benzylcytisine derivatives were obtained, and structurally characterized by NMR spectra and X-ray diffraction. Electron impact mass spectral (EIMS) fragmentations have been investigated and detailed fragmentation pathways have been proposed for all significant ions. For the first time it is shown that cytisine derivatives, under in vitro condition, exhibit promising antiproliferative activities against selected cell lines (A549, MV4-11, NCI-H358, MDA-MB-231, MCF-7, LoVo, HT-29, SK-N-MC). They exhibit lower cytotoxicity against normal murine fibroblasts then cisplatin, the commonly used anticancer drug. N-(4-iodobenzyl)cytisine revealed the strongest antiproliferative activity against lung (NCI-H358) and neuroepithelioma (SK-N-MC; IC50 below 10 μM) cancer cell lines among all compounds studied.