Pyridazine and pyridazinone derivatives: Synthesis and in vitro investigation of their anti-inflammatory potential in LPS-induced RAW264.7 macrophages.

New pyridazine and pyridazinone derivatives 3a-g, 4a-f, 6a, and 6b were designed and synthesized. Cell viability of all compounds was established based on the viability of lipopolysaccharide-induced RAW264.7 macrophage cells determined via the MTT assay. In vitro inhibition assays on human COX-1 and COX-2 enzymes were conducted to probe the newly synthesized compounds' anti-inflammatory activity. The half maximal inhibitory concentration values for the most active compounds, 3d, 3e, and 4e towards COX-2 were 0.425, 0.519, and 0.356 µM, respectively, in comparison with celecoxib. The newly synthesized compounds' ability to inhibit the production of certain proinflammatory cytokines, such as inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-6, and prostaglandin-E2, was also estimated in lipopolysaccharide-induced macrophages (RAW264.7 cells). Compounds 3d and 3e were identified as the most potent cytokine production inhibitors. The results of molecular modeling studies suggested that these compounds were characterized by a reasonable binding affinity toward the active site of COX-2, when compared to a reference ligand. These results might be taken into consideration in further investigations into new anti-inflammatory agents.

Synthesis of novel nicotinic acid derivatives of potential antioxidant and anticancer activity.

This study comprises the design and synthesis of novel nicotinic acid-based cytotoxic agents with selective inhibitory efficacy against the vascular endothelial growth factor receptor-2 (VEGFR-2). Screening of novel compounds for cytotoxicity was assessed against 60 human cancer cell lines. The two most active compounds, 5b and 5c, and the reference drugs sorafenib and doxorubicin were investigated against HCT-15, PC-3, and CF-295 cancer cell lines. Compound 5c exhibited the highest cytotoxic potential compared to doxorubicin against the HCT-15 and PC-3 tumor cell lines. Moreover, it exhibited higher cytotoxic potential and selectivity toward the HCT-15 cell panel compared with sorafenib. Compound 5c demonstrated promising VEGFR-2 inhibition (concentration needed to inhibit cell viability by 50%, IC50 = 0.068 µM) and superior VEGFR-2 selectivity over the epidermal growth factor receptor and platelet-derived growth factor receptor-ß enzymes. It also reduced the total and phosphorylated VEGFR-2 and induced apoptosis, as evidenced by a 4.3-fold rise in caspase-3 levels. The antioxidant potential of the new compounds was determined via measuring the superoxide dismutase (SOD) levels, among which compound 5c exhibited an SOD level almost comparable to ascorbic acid. These results suggested that compound 5c exhibited dual cytotoxic and antioxidant activities. Docking of 5c into the VEGFR-2 pocket showed a similar binding mode to sorafenib. Moreover, the ADME (absorption, distribution, metabolism, and excretion) profile of 5c outlined drug-likeness. Finally, The density functional theory calculations displayed an increased binding affinity of 5c to the target enzyme.

Novel antiproliferative agents bearing substituted thieno[2,3-d]pyrimidine scaffold as dual VEGFR-2 and BRAF kinases inhibitors and apoptosis inducers; design, synthesis and molecular docking.

A series of novel thieno[2,3-d]pyrimidine derivatives was designed and synthesized based on multitarget directed drug design strategy. All the newly synthesized compounds were evaluated for their antiproliferative activity in the National Cancer Institute (NCI) against a panel of 60 tumor cell lines. Compounds 4a and 4b showed a significant antiproliferative activity at 10 µM dose, and were accordingly evaluated at five dose concentrations. They showed potent and broad-spectrum antiproliferative activity, with GI50 values in the micromolar range of 1.44-6.93 µM and 1.66-5.82 µM, respectively. They also showed TGI values in the cytostatic range of 3.49-97.3 µM and 3.33-77.3 µM respectively. These two compounds potently inhibited VEGFR-2 with IC50 = 0.111 ± 0.006 and 0.049 ± 0.003 µM, BRAFV600E with IC50 = 0.089 ± 0.005 and 0.063 ± 0.003 µM and BRAFWT IC50 = 0.071 ± 0.004 and 0.05 ± 0.003 µM, respectively in comparison to sorafenib IC50 values of 0.031 ± 0.002, 0.035 ± 0.002 and 0.021 ± 0.001 µM against VEGFR-2, BRAFV600E and BRAFWT, respectively. Compounds 4a and 4b showed also potent down-regulation of total VEGFR-2 and phosphorylated VEGFR-2. In addition, the HUVECs migratory potential was greatly reduced resulting in significantly disrupted wound healing patterns after treatment with compounds 4a and 4b for 72 h. Furthermore, Compounds 4a and 4b induced apoptosis by 22.82- and 25.81-fold increase in the total apoptosis percentage in breast cancer MCF7 cell line. This apoptotic activity was supported by an increase in the level of apoptotic caspase-9 by 6.17- and 9.07-fold, respectively. Moreover, the cell cycle analysis showed that compounds 4a and 4b arrested the cell cycle mainly in the G1 and G1/S phases, respectively. The molecular modeling studies were performed to assess the binding pattern and affinity of derivatives 4a and 4b toward the VEGFR-2 and BRAF active sites.

Novel thienopyrimidine-aminothiazole hybrids: Design, synthesis, antimicrobial screening, anticancer activity, effects on cell cycle profile, caspase-3 mediated apoptosis and VEGFR-2 inhibition.

A series of novel hybrid compounds of hexahydrobenzo[4,5]thieno[2,3-d]pyrimidine with aminothiazole scaffolds were synthesized. The synthesized compounds were evaluated for their cytotoxic activity against the NCI-60 human tumor cell line panel. Compounds 7c, 7d and 7e exhibited significant antiproliferative activities at 10-5 M dose. Compound 7c exhibited excellent cytotoxic activity against CNS cancer cell lines including SNB-75 and SF-295 as well as renal cancer cell line CAKI-1 when compared with sorafenib as standard anticancer drug. In addition, compound 7d showed almost comparable anticancer activity to sorafenib against SNB-75 cell line and displayed moderate activity against SF-295 and CAKI-1 cell lines in comparison to sorafenib. Compound 7c inhibited the vascular endothelial growth factor receptor 2 (VEGFR-2) with IC50 of 62.48 ± 3.7 nM and decreased both total VEGFR-2 and phosphorylated VEGFR-2 in treated SNB-75 cells suggesting its ability to down regulate cell proliferation, growth, and survival.. The flow cytometric analysis showed that 7c displayed its cytotoxic activity through the reduction of the cellular proliferation and induction of cell cycle arrest at the G2/M phase. Compound 7c clearly boosted the level of the apoptotic caspase-3. All the synthesized compounds were also screened for their antibacterial and antifungal activity against four pathogenic strains of both Gram-positive and Gram-negative as well as Candida albicans. Only compound 7d exhibited antifungal activity against Candida albicans compared to nystatin as the standard antifungal compound.

Synthesis and biological evaluation of new nicotinate derivatives as potential anti-inflammatory agents targeting COX-2 enzyme.

Two novel series derived from nicotinic acid were synthesized and evaluated for their inhibitory activity against cyclooxygenases COX-1 and COX-2, and their selectivity indices were determined. Celecoxib, diclofenac and indomethacin were used as reference drugs. All compounds showed highly potent COX-2 inhibitory activity and higher selectivity towards COX-2 inhibition compared to indomethacin. In addition, these compounds except 3a showed clear preferential COX-2 over COX-1 inhibition compared to diclofenac. Compounds 3b, 3e, 4c and 4f showed COX-2 inhibitory activity equipotent to celecoxib. Compounds 4c and 4f demonstrated selectivity indices 1.8-1.9 fold higher than celecoxib. These two most potent and COX-2 selective compounds were further tested in vivo for anti-inflammatory activity by means of carrageenan induced rat paw edema method. Ulcerogenic activity with histopathological studies were performed. The results showed no ulceration, which implies their safe gastric profile. Compound 4f exhibited the most potent in vivo anti-inflammatory activity comparable to all reference drugs. Further, compounds 4c and 4f were investigated for their influence on certain inflammatory cytokines TNF-α and IL-1ß in addition to PEG2. The findings revealed that these candidates could be identified as promising potent anti-inflammatory agents. Molecular docking of 4c and 4f in the COX-2 active site was performed to rationalize their COX-2 inhibitory potency. The results were found to be in line with the biological findings as they exerted more favorable interactions compared to that of celecoxib, explaining their remarkable COX-2 inhibitory activity.

Novel pyrazolopyrimidine urea derivatives: Synthesis, antiproliferative activity, VEGFR-2 inhibition, and effects on the cell cycle profile.

A series of novel diaryl urea pyrazolopyrimidine derivatives was designed and synthesized. All the synthesized compounds were evaluated for cytotoxic activity by the National Cancer Institute. A significant antiproliferative activity at a 10-µM dose was shown by four compounds (5c, 5e, 5g, and 5h), and they were accordingly evaluated at five concentrations. They showed a potent and broad-spectrum antiproliferative activity, with GI50 values between 0.553 and 3.80 µM and TGI values in the range of 2.17-100 µM. These four compounds potently inhibited the vascular endothelial growth factor receptor-2 (VEGFR-2) with IC50 values in the nanomolar range. Molecular docking attributed their potent VEGFR-2 inhibitory activity to their interactions with key amino acids in the VEGFR-2 active site. Their flow cytometric analysis showed that they exerted their cytotoxic activity by reduction of the cellular proliferation and by induction of cell cycle arrest at the G2/M phase. Additionally, they induced DNA degradation or fragmentation, confirming the role of apoptosis in the cancer cell death and cytotoxicity induced by these compounds.

Synthesis, Characterization and Cytotoxicity of Substituted [1]Benzothieno[3,2-e][1,2,4]triazolo [4,3-a]pyrimidines.

A new series of 4-benzyl-6,7,8,9-tetrahydro[1]benzothieno[3,2-e][1,2,4]triazolo[4,3-a]pyrimidines was synthesized motivated by the widely reported anticancer activity of thieno[2,3-d]pyrimidines and triazolothienopyrimidines. The in vitro cytotoxic activity of some selected compounds was evaluated against two human cell lines: prostate cancer (PC-3) and colon cancer (HCT-116). A preliminary study of the structure-activity relationship of the target compounds was discussed. Most of the synthesized compounds showed remarkable activity on the tested cell lines, while compound 16c had the highest potency against the PC-3 cell line with an IC50 of 5.48 µM compared to Doxorubicin (IC50 = 7.7 µM), the reference standard used in this study. On the other hand, 6c and 18c were the most active against HCT-116 (IC50 = 6.12 and 6.56 µM, respectively) relative to IC50 = 15.82 µM of the standard. Thus, some of the synthesized thienopyrimidine derivatives, specially 6c, 16c and 18c, have the potential to be developed into potent anticancer agents.

Design and Synthesis of Novel Ibuprofen Derivatives as Selective COX-2 Inhibitors and Potential Anti-Inflammatory Agents: Evaluation of PGE2, TNF-α, IL-6 and Histopathological Study.

BACKGROUND: The reported binding mode of ibuprofen in the COX-2 binding site indicated that the carboxylic group binds with Arg-120 and Tyr-355 at the entrance of the cyclooxygenase channel and does not extend into the pocket. This accounted for the non-selectivity of ibuprofen. Based on this fact, we assumed that extending the length of the carboxylic acid moiety in ibuprofen and adding more bulky rigid groups as well as bulky groups carrying H-bonding functions might increase the selectivity and reduce the side effects of ibuprofen while maintaining its analgesic and anti-inflammatory activities. OBJECTIVE: In this work, four series of ibuprofen derivatives were designed and prepared. The compounds were designed by increasing the length of the carboxylate group along with the incorporation of large hydrophobic groups. METHODS: Four series of ibuprofen derivatives were synthesized starting from ibuprofen. Their chemical structure was confirmed by spectral data. All the compounds were tested for their COX inhibitory activity. RESULTS: The best COX-2 activity and selectivity were obtained with compounds 5c and 5d, which were subjected to further in vivo testing (carrageenan-induced paw edema, rat serum PGE2, TNF- α and IL-6, hot plate latency test) to investigate their anti-inflammatory and analgesic activities as well as their effects on the gastric mucosa. The anti-inflammatory activity of both compounds was comparable to that of ibuprofen, diclofenac, and indomethacin. Both compounds suppressed the production of PGE2 as well as the rat serum concentrations of both TNF-α and IL-6. This potent antiinflammatory and analgesic behavior was not accompanied by any effect on the gastric mucosa. Docking simulation studies of the two compounds explained the higher selectivity for the COX-2 enzyme. CONCLUSION: Potent and selective ibuprofen derivatives can be successively obtained by extending the length of the carboxylic acid moiety in ibuprofen and adding more bulky rigid groups as well as bulky groups with H-bonding functions.

Synthesis and anticonvulsant activity of new phenytoin derivatives.

Hybrids between phenytoin and thiosemicarbazide, 1,3,4-oxadiazole, 1,3,4-thiadiazole or 1,2,4-triazole were synthesized and tested for anticonvulsant activity. Preliminary anticonvulsant screening was performed using standard maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) screens in mice. The neurotoxicity was determined applying the rotarod test. Among these compounds, 4 and 5d showed the highest protection (80%) in the scPTZ test at a dose of 100 mg/kg, whereas the compound 5b displayed promising anticonvulsant effect in the MES model.

Phenytoin-based bivalent ligands: design, synthesis and anticonvulsant activity.

Synthesis, characterization and anticonvulsant properties of new bivalent ligands derived from phenytoin were described. Initial anticonvulsant screening was performed using maximal electroshock (MES) and pentylenetetrazole (PTZ) screens in mice. The neurotoxicity for compounds that showed significant anticonvulsant activity was determined applying the rotorod test. Most of the test compounds were found to be effective in at least one seizure model in a dose of 100 mg/kg. Compound 5e exhibited marked anticonvulsant activity in both MES and PTZ screens. The computer-aided prediction of biological activity was carried out.