Affinity of 3-benzylidene- and 3-cinnamylidenemyosmine analogues for Periplaneta americana nicotinic acetylcholine receptors

Abstract

3-Benzylidenemyosmine analogues with substituents at the ortho-, meta-, and para-positions of the phenyl ring and 3-cinnamylidenemyosmine analogues with substituents at a para-position of the phenyl ring were synthesized. The affinity of the synthesized compounds for nicotinic acetylcholine receptors (nAChRs) in the nerve cord of the American cockroach (Periplaneta americana L.) was determined by radioligand binding assay using [3 H]epibatidine. Of the compounds tested, 3-(2,4-dihydroxybenzylidene)myosmine 3 and 3-(4-hydroxybenzylidene) myosmine 4 displayed the highest potency, with IC50 values of 0.120 and 0.310 mM, respectively. 3-(4-Dimethylaminobenzylidene)myosmine 15 with a para-dimethylamino group on the benzylidene moiety displayed moderate affinity (IC505.49 mM). On the other hand, cinnamylidene analogues, 3-(4-dimethylaminocinnamylidene)myosmine 16 and 3-cinnamylidenemyosmine 17, displayed moderate affinity, with IC50 values of 2.07 and 3.52 mM, respectively.