Structure-based design, synthesis, molecular docking study and biological evaluation of 1,2,4-triazine derivatives acting as COX/15-LOX inhibitors with anti-oxidant activities

Design, synthesis and anti-inflammatory assessment of certain substituted 1,2,4-triazoles bearing tetrahydroisoquinoline scaffold as COX 1/2-inhibitors

Aiming to discover effective and safe non-steroidal anti-inflammatory agents, a new set of 1,2,4-triazole tetrahydroisoquinoline hybrids 9a-g, 11a-g and 12a-g was synthesized and evaluated as inhibitors of COX-1 and COX-2. In order to overcome the adverse effects of highly selective COX-2 and non-selective COX-2 inhibitors, the compounds of this study were designed with the goal of obtaining moderately selective COX-2 inhibitors. In this study compounds 9e, 9g and 11f are the most effective derivatives against COX-2 with IC50 values 0.87, 1.27 and 0.58 µM, respectively which are better than or comparable to the standard drug celecoxib (IC50 = 0.82 µM) but with lower selectivity indices as required by our goal design. The results of the in vivo anti-inflammatory inhibition test revealed that compounds 9e, 9g and 11f displayed a higher significant anti-inflammatory activity than celecoxib at all-time intervals. In addition, these compounds significantly decreased the production of inflammatory mediators PGE-2, TNF-ɑ and IL-6. Compounds 9e, 9g and 11f had a safe gastric profile compared to indomethacin, also compound 11f (ulcerogenic index = 1.33) was less ulcerous than the safe celecoxib (ulcerogenic index = 3). Moreover, histopathological investigations revealed a normal architecture of both paw skin and gastric mucosa after oral treatment of rats with compound 11f. Furthermore, molecular docking studies were performed on COX-1 and COX-2 to study the binding pattern of compounds 9e, 9g and 11f on both isoenzymes.

Dual COX-2/15-LOX inhibitors: A new avenue in the prevention of cancer

Dual cyclooxygenase 2/15-lipoxygenase inhibitors constitute a valuable alternative to classical non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 (cyclooxygenase-2) inhibitors for the treatment of inflammatory diseases, as well as preventing the cancer. Indeed, these latter present diverse side effects, which are reduced or absent in dual-acting agents. In this review, COX-2 and 15-LOX (15-lipoxygenase) pathways are first described in order to highlight the therapeutic interest of designing such compounds. Various structural families of dual inhibitors are illustrated. This study discloses various structural families of dual 15-LOX/COX-2 inhibitors, thus pave the way to design potentially-active anticancer agents with balanced dual inhibition of these enzymes.

Magic shotgun approach to anti-inflammatory pharmacotherapy: Synthesis of novel thienopyrimidine monomers/heterodimer as dual COX-2 and 15-LOX inhibitors endowed with potent antioxidant activity

Emerging evidence points to the intertwining framework of inflammation and oxidative stress in various ailments. We speculate on the potential impact of the magic shotgun approach in these ailments as an attempt to mitigate the drawbacks of current NSAIDs. Hence, we rationally designed and synthesized new tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine monomers/heterodimer as dual selective COX-2/15-LOX inhibitors with potent antioxidant activity. The synthesized compounds were challenged with diverse in vitro biological assays. Regarding the monomeric series, compound 5k exerted the highest COX-2 inhibitory activity (IC50 = 0.068 μM, SI = 160.441), while compound 5i showed the highest 15-LOX inhibitory activity (IC50 = 1.97 μM). Surpassing the most active monomeric members, the heterodimer 11 stemmed as the most potent and selective one in the whole study (COX-2 IC50 = 0.065 μM, SI = 173.846, 15-LOX IC50 = 1.86 μM). Heterodimer design was inspired by the cross-talk between the partner monomers of the COX-2 isoform. Moreover, some of our synthesized compounds could significantly reverse the LPS-enhanced production of ROS and proinflammatory cytokines (IL-6, TNF-α, and NO) in RAW 264.7 macrophages. Again, the heterodimer showed the strongest suppressor activity against ROS (IC50 = 18.79 μM) and IL-6 (IC50 = 4.15 μM) production outperforming the two references, celecoxib and diclofenac. Regarding NO suppressor activity, compound 5j (IC50 = 18.62 μM) surpassed the two references. Only compound 5a significantly suppressed TNF-α production (IC50 = 19.68 μM). Finally, molecular modeling simulated the possible binding scenarios of our synthesized thienopyrimidines within the active sites of COX-2 and 15-LOX. These findings suggest that those novel thienopyrimidines are promising leads showing pharmacodynamics synergy against the selected targets.

Design, Synthesis, Biological Evaluation, and Molecular Docking Study of 4,6-Dimethyl-5-aryl/alkyl-2-[2-hydroxy-3-(4-substituted-1-piperazinyl)propyl]pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-diones as Anti-Inflammatory Agents with Dual Inhibition of COX and LOX

In the present study, we characterize the biological activity of a newly designed and synthesized series of 15 compounds 2-[2-hydroxy-3-(4-substituted-1-piperazinyl)propyl] derivatives of pyrrolo[3,4-c]pyrrole 3a-3o. The compounds were obtained with good yields of pyrrolo[3,4-c]pyrrole scaffold 2a-2c with secondary amines in C₂H₅OH. The chemical structures of the compounds were characterized by ¹H-NMR, ¹³C-NMR, FT-IR, and MS. All the new compounds were investigated for their potencies to inhibit the activity of three enzymes, i.e., COX-1, COX-2, and LOX, by a colorimetric inhibitor screening assay. In order to analyze the structural basis of interactions between the ligands and cyclooxygenase/lipooxygenase, experimental data were supported by the results of molecular docking simulations. The data indicate that all of the tested compounds influence the activity of COX-1, COX-2, and LOX.

Novel 1,2,4-triazine-quinoline hybrids: The privileged scaffolds as potent multi-target inhibitors of LPS-induced inflammatory response via dual COX-2 and 15-LOX inhibition

Based on the observed pharmacophoric structural features for the reported dual COX/15-LOX inhibitors and inspired by the abundance of COX/LOX inhibitory activities reported for the 1,2,4-triazine and quinoline scaffolds, we designed and synthesized novel 1,2,4-triazine-quinoline hybrids (8a-n). The synthesized hybrids were evaluated in vitro as dual COXs/15-LOX inhibitors. The new triazine-quinoline hybrids (8a-n) exhibited potent COX-2 inhibitory profiles (IC₅₀ = 0.047-0.32 μM, SI ∼ 20.6-265.9) compared to celecoxib (IC₅₀ = 0.045 μM, SI ∼ 326). Moreover, they revealed potent inhibitory activities against 15-LOX enzyme compared to reference quercetin (IC₅₀ = 1.81-3.60 vs. 3.34 μM). Hybrid 8e was the most potent and selective dual COX-2/15-LOX inhibitor (COX-2 IC₅₀ = 0.047 μM, SI = 265.9, 15-LOX IC₅₀ = 1.81 μM). These hybrids were further challenged by their ability to inhibit NO, ROS, TNF-α, IL-6 inflammatory mediators, and 15-LOX product, 15-HETE, production in LPS-activated RAW 264.7 macrophages cells. Compound 8e was the most potent hybrid in reducing ROS and 15-HETE levels showing IC₅₀ values of 1.02 μM (11-fold more potent than that of celecoxib, IC₅₀ = 11.75 μM) and 0.17 μM (about 43 times more potent than celecoxib, IC₅₀ = 7.46 μM), respectively. Hybrid 8h exhibited an outstanding TNF-α inhibition with IC₅₀ value of 0.40 μM which was about 25 times more potent than that of celecoxib and diclofenac (IC₅₀ = 10.69 and 10.27 μM, respectively). Docking study of the synthesized hybrids into the active sites of COX-2 and 15-LOX enzymes ensures their favored binding affinity. To our knowledge, herein we reported the first 1,2,4-triazine-quinoline hybrids as dual COX/15-LOX inhibitors.

Structure-Based Design, Synthesis, Biological Evaluation and Molecular Docking Study of 4-Hydroxy-N'-methylenebenzohydrazide Derivatives Acting as Tyrosinase Inhibitors with Potentiate Anti-Melanogenesis Activities

Background:

Melanogenesis is a process of melanin synthesis, which is a primary response for the pigmentation of human skin. Tyrosinase is a key enzyme, which catalyzes a ratelimiting step of the melanin formation. Natural products have shown potent inhibitors, but some of these possess toxicity. Numerous synthetic inhibitors have been developed in recent years may lead to the potent anti– tyrosinase agents.

Objective:

A number of 4-hydroxy-N'-methylenebenzohydrazide analogues with related structure to chalcone and tyrosine were constructed with various substituents at the benzyl ring of the molecule and evaluate as a tyrosinase inhibitor. In addition, computational analysis and metal chelating potential have been evaluated.

Methods:

Design and synthesized compounds were evaluated for activity against mushroom tyrosinase. The metal chelating capacity of the potent compound was examined using the mole ratio method. Molecular docking of the synthesized compounds was carried out into the tyrosine active site.

Results:

Novel 4-hydroxy-N'-methylenebenzohydrazide derivatives were synthesized. The two compounds 4c and 4g showed an IC50 near the positive control, led to a drastic inhibition of tyrosinase. Confirming in vitro results were performed via the molecular docking analysis demonstrating hydrogen bound interactions of potent compounds with histatidine-Cu+2 residues with in the active site. Kinetic study of compound 4g showed competitive inhibition towards tyrosinase. Metal chelating assay indicates the mole fraction of 1:2 stoichiometry of the 4g-Cu2+ complex.

Conclusion:

The findings in the present study demonstrate that 4-Hydroxy-N'- methylenebenzohydrazide scaffold could be regarded as a bioactive core inhibitor of tyrosinase and can be used as an inspiration for further studies in this area.

Novel chalcone derivatives containing a 1,2,4-triazine moiety: design, synthesis, antibacterial and antiviral activities

A series of novel chalcone derivatives containing the 1,2,4-triazine moiety were synthesized and their structures were confirmed by 1H NMR, 13C NMR and elemental analyses. Antiviral bioassays revealed that most of the compounds exhibited good antiviral activity against tobacco mosaic virus (TMV) at a concentration of 500 μg mL-1. The designated compound 4l was 50% effective in terms of curative and protective activities against TMV with 50% effective concentrations (EC50) of 10.9 and 79.4 μg mL-1, which were better than those of ningnanmycin (81.4 and 82.2 μg mL-1). Microscale thermophoresis (MST) also showed that the binding of compound 4l to coat protein (TMV-CP) yielded a K d value of 0.275 ± 0.160 μmol L-1, which was better than that of ningnanmycin (0.523 ± 0.250 μmol L-1). At the same time, molecular docking studies for 4l with TMV-CP (PDB code:1EI7) showed that the compound was embedded well in the pocket between the two subunits of TMV-CP. Meanwhile, compound 4a demonstrated excellent antibacterial activities against Ralstonia solanacearum (R. solanacearum), with an EC50 value of 0.1 μg mL-1, which was better than that of thiodiazole-copper (36.1 μg mL-1) and bismerthiazol (49.5 μg mL-1). The compounds act by causing folding and deformation of the bacterial cell membrane as observed using scanning electron microscopy (SEM). The chalcone derivatives thus synthesized could become potential alternative templates for novel antiviral and antibacterial agents.

Synthesis of diarylidenecyclohexanone derivatives as potential anti-inflammatory leads against COX-2/mPGES1 and 5-LOX

This study establishes the diarylidenecyclohexanones as good anti-inflammatory pharmacophores with selective high potency against PGE₂and 5-LOX without toxicity towards healthy human cells.

Anti-inflammatory activity of triazine derivatives: A systematic review

Triazines are heterocyclic compounds with a variety of biological activities that have been increasingly studied in recent years due to their versatile structure (three isoforms) and the different derivatives that can be synthesized from them to ensure functional motifs. This systematic review provides the evidence in the literature of the in vitro and in vivo anti-inflammatory activity of triazine derivatives from 2008 to June 2018. Four bibliographical databases were consulted (PubMed, Web of Science, EMBASE and Scopus), and a total of 48 studies were included in this paper based on our eligibility criteria. Although 35.17% of evaluated triazines were demonstrated to be promising anti-inflammatory agents, further studies need to be conducted to explore their pharmacological profiles in the medical research of drug discovery to control the risk factors and pathophysiology of several chronic inflammation-based diseases.

Flavonoids as potent allosteric inhibitors of protein tyrosine phosphatase 1B: molecular dynamics simulation and free energy calculation

Protein tyrosine phosphatase 1B (PTP1B) is a member of the PTP superfamily which is considered to be a negative regulator of insulin receptor (IR) signaling pathway. PTP1B is a promising drug target for the treatment of type 2 diabetes, obesity, and cancer. The existence of allosteric site in PTP1B has turned the researcher's attention to an alternate strategy for inhibition of this enzyme. Herein, the molecular interactions between the allosteric site of PTP1B with three non-competitive flavonoids, (MOR), (MOK), and (DPO) have been investigated. Three ligands were docked into allosteric site of the enzyme. The resulting protein-ligand complexes were used for molecular dynamics studies. Principal component and free-energy landscape (FEL) as well as cluster analyses were used to investigate the conformational and dynamical properties of the protein and identify representative enzyme substrates bounded to the inhibitors. Per residue energy decomposition analysis attributed dissimilar affinities of three inhibitors to the several hydrogen bonds and non-bonded interactions. In conclusion, our results exhibited an inhibitory pattern of the ligands against PTP1B.

Novel series of 1,2,4-trioxane derivatives as antimalarial agents

Among three series of 1,2,4-trioxane derivatives, five compounds showed good in vitro antimalarial activity, three compounds of which exhibited better activity against P. falciparum resistant (RKL9) strain than the sensitive (3D7) one. Two best compounds were one from aryl series and the other from heteroaryl series with IC₅₀ values of 1.24 µM and 1.24 µM and 1.06 µM and 1.17 µM, against sensitive and resistant strains, respectively. Further, trioxane derivatives exhibited good binding affinity for the P. falciparum cysteine protease falcipain 2 receptor (PDB id: 3BPF) with well defined drug-like and pharmacokinetic properties based on Lipinski's rule of five with additional physicochemical and ADMET parameters. In view of having antimalarial potential, 1,2,4-trioxane derivative(s) reported herein may be useful as novel antimalarial lead(s) in the discovery and development of future antimalarial drug candidates as P. falciparum falcipain 2 inhibitors against resistant malaria.

Discovery of 5,6-diaryl-1,2,4-triazines hybrids as potential apoptosis inducers

A series of 5,6-diaryl-1,2,4-triazines hybrids bearing a 1,2,3-triazole linker were synthesized by molecular hybridization strategy and evaluated for antiproliferative activity against three selected cancer cell lines (MGC-803, EC-109 and PC-3). The first structure-activity relationship (SAR) for these 5,6-diaryl-1,2,4-triazines is explored in this report with evaluation of 15 variants of the structural class. Among these chemical derivatives, 3-(((1-(4-fluorobenzyl)-1H-1,2,3-triazol-4-yl)methyl)thio)-5,6-diphenyl-1,2,4-triazine (11E) showed the more potent inhibitory effect against three cell lines than 5-Fu. Cellular mechanism studies in MGC-803 cells elucidated 11E inhibited colony formation and arrested cell cycle at G2/M phase. Furthermore, compound 11E caused morphological changes, decreased mitochondrial membrane potential, and induced apoptosis through the apoptosis-related proteins in MGC-803 cells. It was the first time, to our knowledge, that 5,6-diaryl-1,2,4-triazines bearing a 1,2,3-triazole linker were used as potential apoptosis inducers.