Synthesis, biological evaluation and molecular docking studies of novel 2-alkylthiopyrimidino-tacrines as anticholinesterase agents and their DFT calculations

1,2,3-Triazolo[4,5-b]aminoquinolines: Design, synthesis, structure, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity, and molecular docking of novel modified tacrines

An efficient [4 + 2] cyclization protocol to synthesize a series of twelve examples of 1,2,3-triazolo[4,5-b]aminoquinolines (5) as novel structurally modified tacrines was obtained by reacting readily accessible precursors (i.e., 3-alky(aryl)-5-amino-1,2,3-triazole-4-carbonitriles (3)) and selected cycloalkanones (4) of five-, six-, and seven-membered rings. We evaluated the AChE and BChE inhibitory activity of the novel modified tacrines 5, and the compound derivatives from cyclohexanone (4b) showed the best AChE and BChE inhibitory activities. Specifically, 1,2,3-triazolo[4,5-b]aminoquinolines 5bb obtained from 3-methyl-carbonitrile (3b) showed the highest AChE (IC50 = 12.01 μM), while 5ib from 3-sulfonamido-carbonitrile (3i) was the most significant inhibitor for BChE (IC50 = 1.78 μM). In general, the inhibitory potency of compound 5 was weaker than the pure tacrine reference, and our findings may help to design and develop novel anticholinesterase drugs based on modified tacrines.

Anti-cholinesterase, anti-inflammatory and antioxidant properties of Combretum micranthum G. Don: Potential implications in neurodegenerative disease

Background

Brain damage is a severe and common pathology that leads to life-threatening diseases. Despite development in the research, the medical evidence of the effectiveness of potential neuroprotective medicines is insufficient. As a result, there is an immense and urgent demand for promising medication. For millennia, herbal remedies were a fundamental aspect of medical treatments. Combretum micranthum (CM), a plant of the family Combretaceae in sub-Saharan Africa, has been utilized in folklore medicine to cure diverse human ailments. In order to develop a neuroprotective phytomedicine, the current research was undertaken to explore the antioxidant, anti-inflammatory, anticholinesterase and neuroprotective potential of CM extract.

Methods

Colorimetric methods were used to determine CM antioxidant activity, in-vitro protein denaturation and membrane destabilization assays were used to evaluate its anti-inflammatory capacity, anticholinesterase activity was carried out using Ellman's method, and neuroprotective potential was assessed on brain homogenate stressed with ferric chloride and ascorbic acid (FeCl₂-AA) by assessing the lipoperoxidation biomarker malondialdehyde (MDA).

Results

In Ferric Reducing Antioxidant Power (IC₅₀ = 27.15 ± 0.06 µg/mL) and Total Antioxidant Capacity (IC₅₀ = 31.13 ± 0.02 µg/mL), CM extract demonstrated strong antioxidant activity. Anti-inflammatory effect were improved in heat-induced Egg albumin and BSA denaturation (IC ₅₀ = 46.35 ± 1.53 and 23.94 ± 1.10 µg/mL) as well as heat and hypotonia induced membrane destabilization (IC ₅₀ = 20.96 ± 0.11 and 16.75 ± 0.94 µg/mL).CM extract showed strong anticholinesterase activity (IC ₅₀ = 59.85 ± 0.91 µg/mL). In an ex-vivo neuroprotective model, CM extract showed substantial inhibition (p < 0.001) of oxidative damage caused by FeCl₂-AA in brain tissue.

Conclusion

C. micranthum may be a good candidate for its probable neuroprotective potential. Its neuroprotective benefits might be attributed to its antioxidant, anti-inflammatory and anticholinesterase effects.

Friedlӓnder's synthesis of quinolines as a pivotal step in the development of bioactive heterocyclic derivatives in the current era of medicinal chemistry

In the current scenario of medicinal chemistry, quinoline plays a pivotal role in the design of new heterocyclic compounds with several pharmacological properties, so the search for new synthetic methodologies and their application in drug discovery has been widely studied. So far, many procedures have been performed for the preparation of quinoline scaffolds, among which Friedländer quinoline synthesis plays an important role in obtaining these heterocycles. The Friedländer reaction involves condensation between 2-aminobenzaldehydes and keto-compounds. The quinoline nucleus, once obtained through the Friedländer synthesis, has been extensively modified so that these derivatives can exhibit a large number of biological activities such as anticancer, antimalarial, antimicrobial, antifungal, antituberculosis, and antileishmanial properties. In this work, the focus is on the applicability of the Friedländer reaction in the synthesis of various types of bioactive heterocyclic quinoline compounds, which to date has not been reported in the context of medicinal chemistry. The main part of this review selectively focuses on research from 2010 to date and will present highlights of the Friedländer quinoline synthesis procedures and findings to address biological and pharmacological activities.

Design, synthesis, crystal structure, in vitro cytotoxicity evaluation, density functional theory calculations and docking studies of 2-(benzamido) benzohydrazide derivatives as potent AChE and BChE inhibitors

A series of hydrazone derivatives of 2-(benzamido) benzohydrazide was designed, synthesized, and characterized utilizing FTIR, NMR and UV spectroscopic techniques along with mass spectrometry. Compound 10 was also characterized through X-ray crystallography. These synthesized compounds were assessed for their potential as anti-Alzheimer's agents by checking their AChE and BChE inhibition properties by in vitro analysis. The synthesized derivatives were also evaluated for their antioxidant potential along with cytotoxicity studies. The results clearly indicated that dual inhibition of both the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) was achieved by most of the compounds (03-13), showing varying IC50values. Remarkably, compound 06 (IC50 = 0.09 ± 0.05 for AChE and 0.14 ± 0.05 for BChE) and compound 13 (IC50 = 0.11 ± 0.03 for AChE and 0.10 ± 0.06 for BChE) from the series showed IC50 values comparable to the standard donepezil (IC50 = 0.10 ± 0.02 for AChE and 0.14 ± 0.03 for BChE). Moreover, the derivative 11 also exhibited selective inhibition against BChE with IC50 = 0.12 ± 0.09. Meanwhile, compounds 04 and 10 exhibited good anti-oxidant activities, showing % scavenging of 95.06% and 82.55%, respectively. Cytotoxicity studies showed that the synthesized compounds showed cell viability greater than 80%; thus, these compounds can be safely used as drugs. DFT and molecular docking studies also supported the experimental findings.