Schiff Base Derivatives of 4-Aminoantipyrine as Promising Molecules: Synthesis, Structural Characterization, and Biological Activities

In this study, some Schiff bases derived from 4-aminoantipyrine (4-AAP) ( VI – X ) were synthesized, characterized by elemental analysis (C, H, N) and three spectral techniques (FT-IR, 1 H, and 13 C NMR), and then their antioxidant activity was investigated by employing four different methods. Subsequently, the inhibitory influences of the synthesized molecules against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase enzymes were tested. More importantly, the cytotoxic effects of all title molecules were also evaluated on HeLa human cervical cancer and L929 mouse fibroblast cell lines. According to the results obtained, compound ( VI ) (IC 50 : 16.82 ± 0.17 μM) showed higher ABTS cation radical scavenging activity than BHA (IC 50 : 17.59 ± 0.10 μM). In CUPRAC assay, it was determined that the activity ordering of the bioactive molecules has been determined as VII > X > VII > α-TOC > IX > I > II > V > VI . In AChE assay, compound ( I ) indicated a high potent inhibition activity with 91.75 ± 1.15% better than galanthamine. In BChE assay, compound ( VII ) had good BChE inhibition activity (78.76 ± 1.47%) better than galanthamine. Compound ( V ) showed strong tyrosinase inhibition activity with 52.85 ± 0.23% value at 200 μM concentration. Compound ( III ) showed the best cytotoxic effect on HeLa cells with an IC 50 dose of 21.47 µM. Consequently, it can be said that some of these synthesized molecules were potentially new anti-Alzheimer drug candidate molecules.