Antioxidant and anticholinesterase activities of some dialkylamino substituted 3-hydroxyflavone derivatives

Background: Flavones, are a class of naturally occuring polyphenolic compounds which have 2-phenylchromen-4-one structure. Various studies showed that flavones have several pharmacological activities such as antioxidant, anti-inflammatory, antimicrobial, cytotoxic, antitumour and antiallergic. In the present study, 3-hydroxyflavones also called flavonols, posessing 4'-dialkylamino moiety were synthesized, and their antioxidant and anticholinesterase activities were investigated by comparison with unmodified 3-hydroxflavone. Method: For investigation of antioxidant potential, radical scavenging assays (DPPH•, ABTS⁺, O₂-) were used along with CUPRAC and lipid peroxidation inhibitory assays, as well as anticholinesterase activity by Ellman method. Results: The best results were obtained for 4'-N, N-dimethyl flavonol (1) in both antioxidant and anticholinesterase activity tests, possibly due to its least steric hinderance effect. It exhibited remarkable DPPH free radical scavenging activity (2.43±0,09 μg/mL) competing with a standard compound quercetin (2.10±0,10 μg/mL). Moreover, the other tested flavonols also showed high antioxidant activities. Compounds 5 and 6 exhibited close IC₅₀ values to those of compound 1. Conclusion: Antioxidant activity test results were found to be well correlated with anticholinesterase activity test results indicating possible role of antioxidant compounds in the treatment of Alzheimer's disease.