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.

Target Recognition Molecules and Molecular Modeling Studies.

Targeted delivery systems aim to deliver drugs to their intended site of action and as such they are expected to show more desired effects and less unwanted effects. The system itself is composed of a vesicle-encapsulated drug with "target recognition molecules" on the envelop. Ideally, these target recognition molecules, being either small non-peptidic molecules or peptides, are basically high-affinity ligands for a receptor or other protein that is expressed specifically and at high concentrations on the target cells. This review will focus on several widely used examples of target recognition molecules and on how molecular modelling studies have been used in the development of nano drug carrier systems in general.