Synthesis and in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes activity of aldehyde and Schiff base substituted cobalt (II), copper (II), and zinc (II) phthalocyanines

Abstract

In this work, a series of aldehyde‐substituted phthalocyanine compounds (1, 3, and 5) were prepared by the cyclotetramerization of the 4‐(5‐(diethylamino)‐2‐formylphenoxy) phthalonitrile (a) and the corresponding metal salts. Schiff base‐substituted phthalocyanines (2, 4, and 6) were derived from an aldehyde‐substituted phthalocyanine (1, 3, and 5) via the reaction of aldehyde‐substituted phthalocyanines with an amine reagent. The compounds that were obtained were characterized using FT‐IR, 1H {13C} NMR, UV–Vis, and MS spectra (a and 1–6). The inhibitory qualities of synthesized aldehyde and Schiff base‐substituted complexes against the enzymes butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) were assessed. The majority of phthalocyanines exhibited strong enzyme‐inhibiting properties. Out of the six produced phthalocyanines, 3 and 4 displayed the most intriguing profiles as submicromolar selective AChE inhibitors (IC50 = 0.060 μM), whereas 1 demonstrated the most potent BChE inhibitor (IC50 = 0.024 μM). The aggregation studies of CoPcs, CuPcs, and ZnPcs (1–6) were also carried out in this work.