Publications by authors named "Nafisah Al-Rifai"

A library of -benzylpyridinium-based compounds, and , was designed and synthesised as potential acetylcholinesterase) AChE (inhibitors. An assay for the synthesised compounds showed that most compounds had significant AChE inhibitory activities at the nanomolar and submicromolar levels. The benzyl () and fluoro () derivatives were the most active, with IC values ≤56 nM.

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Given that impurities may affect the quality and safety of drug products, impurity identification and profiling is an integral part of drug quality control and is particularly important for newly developed medications such as solriamfetol, which is used to treat excessive daytime sleepiness. Although the high-performance liquid chromatography analysis of commercial solriamfetol has revealed the presence of several impurities, their synthesis, structure elucidation, and chromatographic determination have not been reported yet. To bridge this gap, we herein identified, synthesized, and isolated eight process-related solriamfetol impurities, characterized them using spectroscopic and chromatographic techniques, and proposed plausible mechanisms of their formation.

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Cell protection against different noxious stimuli like oxidative stress or chemical toxins plays a central role in the treatment of many diseases. The inducible heme oxygenase isoform, heme oxygenase-1 (HO-1), is known to protect cells against a variety of harmful conditions including apoptosis. Because a number of medium strong electrophiles from a series of α-X-substituted 2',3,4,4'-tetramethoxychalcones (α-X-TMCs, X = H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) had proven to activate Nrf2 resulting in HO-1 induction and inhibit NF-κB downstream target genes, their protective effect against staurosporine induced apoptosis and reactive oxygen species (ROS) production was investigated.

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Article Synopsis
  • Inflammatory signaling pathways play a crucial role in how cells respond to infections and injuries, and compounds that alkylate cysteinyl thiols can modulate these pathways.
  • A study tested fourteen chalcone derivatives for their effects on inflammatory responses by measuring their influence on specific enzymes and cytokine expression.
  • It was found that while most compounds demonstrated expected anti-inflammatory activity related to their thiol alkylating ability, the strongest electrophiles (like CN and NO2) did not exhibit the same anti-inflammatory effects, highlighting the importance of carefully adjusting chemical properties for therapeutic purposes.
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Signal transducer and activator of transcription STAT5 and its upstream activating kinase JAK2 are essential mediators of cytokine signaling. Their activity is normally tightly regulated and transient. However, constitutive activation of STAT5 is found in numerous cancers and a driving force for malignant transformation.

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Thiol-mediated processes play a key role to induce or inhibit inflammation proteins. Tailoring the reactivity of electrophiles can enhance the selectivity to address only certain surface cysteines. Fourteen 2',3,4,4'-tetramethoxychalcones with different α-X substituents (X=H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) were synthesized, containing the potentially electrophilic α,β-unsaturated carbonyl unit.

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Article Synopsis
  • The electrophilic properties of chalcones and similar compounds are key to their biological effects, particularly in processes involving thiols.
  • A new screening method was created to measure the second-order rate constants (k(2)) for thia-Michael additions, helping in evaluating their biological potential.
  • The study identified a clear structure-activity relationship among 16 hydroxy-alkoxychalcones, while also measuring k(2) values for curcumin and cinnamaldehyde, noting that cinnamic acids or esters reacted very slowly or not at all.
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