In this work, we report the application of Buchwald-Hartwig amination for the preparation of new derivatives of quercetin and luteolin. Our investigation delves into the impact of aniline moiety on antioxidant, and anti-inflammatory activity, cytotoxicity, and the ability of flavonoids to modulate drug-resistance mechanisms in bacteria. The anti-inflammatory activity disappeared after the introduction of aniline into the flavonoids and the cytotoxicity remained low. Although the ability of quercetin and luteolin to modulate bacterial resistance to antibiotics has already been published, this is the first report on the molecular mechanism of this process. Both flavonoids attenuate erythromycin resistance by suppressing the ribosomal methyltransferase encoded by the ermA gene in Staphylococcus aureus. Notably, 4-(trifluoromethyl)anilino quercetin emerged as a potent ErmA inhibitor, likely by interacting with the RNA-binding pocket of ErmA. Additionally, both 4-fluoroanilino derivatives effectively impended the staphylococcal efflux system. All the prepared derivatives exhibited superior activity in modulating gentamicin resistance in S. aureus compared to the parent compounds. Overall, the incorporation of substituted anilines into the flavonoid core significantly enhanced its ability to combat multidrug resistance in bacteria.

• Publication type
• Journal Article MeSH

A novel series of 6-chlorotacrine-scutellarin hybrids was designed, synthesized and the biological activity as potential anti-Alzheimer's agents was assessed. Their inhibitory activity towards human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE), antioxidant activity, ability to cross the blood-brain barrier (BBB) and hepatotoxic profile were evaluated in vitro. Among these compounds, hybrid K1383, bearing two methylene tether between two basic scaffolds, was found to be very potent hAChE inhibitor (IC50 = 1.63 nM). Unfortunately, none of the hybrids displayed any antioxidant activity (EC50 ≥ 500 μM). Preliminary data also suggests a comparable hepatotoxic profile with 6-Cl-THA (established on a HepG2 cell line). Kinetic studies performed on hAChE with the most active compound in the study, K1383, pointed out to a mixed, non-competitive enzyme inhibition. These findings were further corroborated by docking studies.

• Keywords
• 6-chlorotacrine, Alzheimer’s disease, acetylcholinesterase, butyrylcholinesterase, enzyme inhibitor, scutellarin,
• MeSH
• Acetylcholinesterase metabolism   MeSH
• Enzyme Activation drug effects   MeSH
• Alzheimer Disease enzymology   MeSH
• Apigenin chemistry   MeSH
• Butyrylcholinesterase metabolism   MeSH
• Cholinesterase Inhibitors chemical synthesis   chemistry   pharmacology   MeSH
• Glucuronates chemistry   MeSH
• Blood-Brain Barrier metabolism   MeSH
• Humans MeSH
• Drug Design MeSH
• Molecular Docking Simulation MeSH
• Tacrine analogs & derivatives   chemistry   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 6-chlorotacrine MeSH Browser
• Acetylcholinesterase MeSH
• Apigenin MeSH
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH
• Glucuronates MeSH
• scutellarin MeSH Browser
• Tacrine MeSH