Improved synthesis, molecular modeling and anti-inflammatory activity of new fluorinated dihydrofurano-naphthoquinone compounds.

A series of new fluorinated dihydrofurano-napthoquinone compounds were sucessfully synthesized in good yields using microwave-assisted multi-component reactions of 2-hydroxy-1,4-naphthoquinone, fluorinated aromatic aldehydes, and pyridinium bromide. The products were fully characterized using spectroscopic techniques and evaluated for their anti-inflammatory activity using lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. Among 12 new compounds, compounds 8b, 8d, and 8e showed high potent NO inhibitory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC50 values ranging from 1.54 to 3.92 µM. The levels of pro-inflammatory cytokines IL-1ß and IL-6 in LPS-stimulated RAW264.7 macrophages were remarkably decreased after the application of 8b, 8d, 8e and 8k. Molecular docking simulations revealed structure-activity relationships of 8b, 8d, and 8e toward NO synthase, cyclooxygenase (COX-2 over COX-1), and prostaglandin E synthase-1 (mPGES-1). Further physicochemical and pharmacokinetic computations also demonstrated the drug-like characteristics of synthesized compounds. These findings demonstrated the importance of fluorinated dihydrofurano-napthoquinone moieties in the development of potential anti-inflammatory agents.

Synthesis of new DOPO derivatives and investigation of their synergistic effect with APP-PEI on the flame retardancy of epoxy composite.

Epoxy resin has been extensively used in many industrial and daily applications due to its unique properties. However, the high flammability of epoxy has limited its further development. DOPO derivatives, which are organophosphorus compounds, are highly effective components of flame retardant epoxy composites due to their good compatibility with the resin and their lower toxicity compared to halogenated compounds. This study synthesized sixteen new DOPO derivatives, characterizing their chemical structures with NMR spectroscopy. The combination of synthesized DOPO derivatives and APP-PEI (ammonium polyphosphate-polyethyleneimine) has shown a synergistic effect on enhancing the flame retardancy of epoxy resin with the UL-94 V-0 rating and the LOI value of 28.6%. Moreover, the epoxy composites displayed relatively high mechanical performance with the impact strength of 26-28 kJ m-2.

Synthesis, molecular docking analysis and in vitro evaluation of new heterocyclic hybrids of 4-aza-podophyllotoxin as potent cytotoxic agents.

Two different synthetic approaches to novel heterocyclic hybrid compounds of 4-azapodophyllotoxin were investigated. The obtained products were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry. MTT protocol was then performed to examine the cytotoxic activity of these products against KB, HepG2, A549, MCF7, and Hek-293 cell lines. The cytotoxic assessment indicated that all products displayed moderate to high cytotoxicity against all tested cancer cell lines. The most active compound 13k containing the 2-methoxypyridin-4-yl group exhibited selective cytotoxicity against KB, A549, and HepG2 cell lines with the IC50 values ranging from 0.23 to 0.27 µM, which were between 5- to 10-fold more potent than the positive control ellipticine. Compounds 13a (HetAr = thiophen-3-yl) and 13d (HetAr = 5-bromofuran-2-yl) displayed high cytotoxic selectivity for A549 and HepG2 cancer cell lines when compared to the other cancer cell lines and low toxicity to the normal Hek-293 cell line. Molecular docking study was conducted to evaluate the interaction of new synthesized compounds with the colchicine-binding-site of tubulin. Besides that, physicochemical and pharmacokinetic properties of the most active compounds 13h,k were predicted.

Microwave-Assisted Three-Component Synthesis of Novel N-Arylated-Dihydrobenzo[g]quinoline-5,10-Diones and Their Potential Cytotoxic Activity.

A convenient three-component synthetic approach was developed en route to new and significative N-arylated-dihydrobenzo[g]quinoline-5,10-diones using 2-hydroxy-1,4-naphthoquinone, a variety of aromatic aldehydes, and 4-(arylamino)furan-2(5H)-ones. A sequence of steps including Knoevenagel condensation, Michael addition, [1,3]-hydrogen shift, intramolecular cyclization and dehydration led to the formation of products. All the products were structurally characterized by spectroscopic techniques and assessed in terms of their cytotoxicity profile against four cancer cell lines (KB, HepG2, A549, and MCF7), and human embryonic kidney (Hek-293) cell lines.

Synthesis and biological activity, and molecular modelling studies of potent cytotoxic podophyllotoxin-naphthoquinone compounds.

A new approach for the synthesis of podophyllotoxin-naphthoquinone compounds using microwave-assisted three-component reactions is reported in this study. Novel podophyllotoxin-naphthoquinone derivatives with modification on ring E were synthesized. All the synthetic compounds were assessed in terms of their cytotoxicity profile against four cancer cell lines (KB, HepG2, A549, and MCF7), and noncancerous Hek-293 cell lines. Notably, treatment of SK-LU-1 cells with compounds 5a and 5b resulted in G2/M phase arrest of the cell cycle, caspase-3/7 activation, and apoptosis. Additionally, molecular docking studies were performed and showed important interaction of two compounds against residues in the colchicine-binding-site of tubulin as well. Taken together, compounds 5a and 5b were identified as potent anticancer agents.

Synthesis and biological evaluation of novel benzo[a]pyridazino[3,4-c]phenazine derivatives.

A convenient microwave-assisted one-pot four-component synthetic approach was developed en route to novel functionalized benzo[a]pyridazino[3,4-c]phenazine derivatives starting from 2-hydroxy-1,4-naphthoquinone, aromatic aldehydes, methyl hydrazine and o-phenylenediamine. Nine new derivatives were successfully synthesized and subsequently evaluated in terms of their biological profiles. The results revealed good cytotoxic activities of compounds 6a, 6h against KB, HepG2, Lu1 and MCF7 human cancer cell lines. Besides that, compound 6d exhibited promising antimicrobial activities toward Staphylococcuc aureus and Bacillus subtilis bacterial strains with IC50 < 6 µM.

Synthesis of novel potent cytotoxicy podophyllotoxin-naphthoquinone compounds via microwave-assited multicomponent domino reactions.

A series of novel podophyllotoxin-naphthoquinone compounds 5a-p were synthesized in good yields using microwave-assisted four-component reactions of 2-hydroxy-1,4-naphthoquinone, aromatic benzaldehydes, tetronic acid and ammonium acetate. All the synthesized compounds were fully characterized by spectral data and evaluated for their cytotoxicity activities against KB, HepG2, Lu1, MCF7, and non-cancerous Hek-293 cell lines. Among 16 new compounds screened, compounds 5a, 5d, 5h, and 5k displayed high potent inhibitory activities with IC50 < 40 nM against HepG2 and SK-Lu-1 cell lines, and showed lower toxicity for non-cancerous Hek-293 cell line, demonstrating the potential importance of these compounds in the development of potential anticancer agents.

Probing the side chain tolerance for inhibitors of the CD95/PLCγ1 interaction.

Proceeding our effort to study protein-protein interaction between the death receptor CD95 and phospholipase PLCγ1, we present in the current work chameleon-like traits of peptidomimetic inhibitors. Minute analysis of the interaction suggests that most of the binding energy relies on van der Waals contacts rather than more specific features, such as hydrogen bonds or salt bridges. The two most important positions of the peptoid for its interaction with PLCγ1 (Arg184 and Arg187) were modified to test this hypothesis. While Arg184 proves to be exchangeable for Trp, with no alteration in affinity, the nature of the amino acid replacing Arg187 is more dependent on its positive charge. However, affinity can be partially recovered by increasing van der Waals interactions. Overall, this study shows that for both positions, a subtle balance exists between hydrophobicity, surface contacts and affinity for CD95/PLCγ1, and provides information for the generation of new therapeutic compounds toward this druggable target.

Synthesis of peptidomimetics and chemo-biological tools for CD95/PLCγ1 interaction analysis.

The death receptor CD95 (also known as Fas) induces apoptosis through protein/protein association and the formation of the death-inducing signaling complex. On the other hand, in certain biological conditions, this receptor recruits different proteins and triggers the formation of another complex designated motility-inducing signaling complex, which promotes cell migration and inflammation. This pathway relies on a short sequence of CD95, called calcium-inducing domain (CID), which interacts with the phospholipase PLCγ1. To better understand how CID/PLCγ1 interaction occurs, we synthesized different α-AA peptides mimicking CID. Some of these peptidomimetics are as potent as the natural peptide to disrupt the CID/PLCγ1 interaction and cell migration, and showed improved pharmacokinetic properties. We also generated biotinyl- and palmitoyl-labelled peptidomimetics, useful chemico-biological tools to further explore the pro-inflammatory signal of CD95, which plays an important role in the pathogenesis of lupus and other autoimmune diseases.

Disrupting the CD95-PLCγ1 interaction prevents Th17-driven inflammation.

CD95L is a transmembrane ligand (m-CD95L) that is cleaved by metalloproteases to release a soluble ligand (s-CD95L). Unlike m-CD95L, interaction between s-CD95L and CD95 fails to recruit caspase-8 and FADD to trigger apoptosis and instead induces a Ca2+ response via docking of PLCγ1 to the calcium-inducing domain (CID) within CD95. This signaling pathway induces accumulation of inflammatory Th17 cells in damaged organs of lupus patients, thereby aggravating disease pathology. A large-scale screen revealed that the HIV protease inhibitor ritonavir is a potent disruptor of the CD95-PLCγ1 interaction. A structure-activity relationship approach highlighted that ritonavir is a peptidomimetic that shares structural characteristics with CID with respect to docking to PLCγ1. Thus, we synthesized CID peptidomimetics abrogating both the CD95-driven Ca2+ response and transmigration of Th17 cells. Injection of ritonavir and the CID peptidomimetic into lupus mice alleviated clinical symptoms, opening a new avenue for the generation of drugs for lupus patients.

Design, synthesis and evaluation of novel hybrids between 4-anilinoquinazolines and substituted triazoles as potent cytotoxic agents.

In this research several series of novel dioxygenated ring fused 4-anilinoquinazolines (10a-d) and 4-anilinoquinazoline-substituted triazole hybrid compounds (11-14) have been designed and synthesized. Their biological significance was highlighted by evaluating in vitro for anticancer activities, wherein several compounds displayed excellent activity specifically against three human cancer cell lines (KB, epidermoid carcinoma; HepG2, hepatoma carcinoma; SK-Lu-1, non-small lung cancer). Especially, compound 13a exhibited up to 100-fold higher cytotoxicity in comparison with erlotinib. Docking the most cytotoxic compounds (11d, 13a, 13b, and 14c) into the ATP binding site of different EGFR tyrosine kinase domains was perfomed to predict the analogous binding mode of these compounds to the EGFR targets.

Synthesis and cytotoxic evaluation of novel indenoisoquinoline-substituted triazole hybrids.

The synthesis of various substituted triazole-indenoisoquinoline hybrids was performed based on a CuI-catalyzed 1,3-cycloaddition between propargyl-substituted derivatives and the azide-containing indenoisoquinoline. Besides, a variety of N-(alkyl)propargylindenoisoquinolines was used as substrates for the construction of triazole-indenoisoquinoline-AZT conjugated via a click chemistry-mediated coupling with 3'-azido-3'-deoxythymidine (AZT). Thus, twenty three new indenoisoquinoline-substituted triazole hybrids were successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity of four triazole linker-indenoisoquinoline-AZT hybrids in KB and HepG2 cancer cell lines.