Development of safe and antioxidant COX-2 inhibitors; Synthesis, molecular docking analysis and biological evaluation of novel pyrrolizine 5-carboxamides

In the current study, a series of new pyrrolizine-5-carboxamide derivatives (5-8, 9a-d, 10a-d, 11a,b and 12a,b) were developed, synthesized and evaluated in terms of in vitro COX-2 enzyme inhibition. The in vivo anti-inflammatory evaluation was conducted on the most selective compounds (9a,b,d, 10b,c and 11a,b). For the most active five compounds (9a, 10b,c and 11a,b), ulcerogenic liability, histopathological examinations, physicochemical properties study and antioxidant activity were investigated. Also, nitric oxide donor activity was evaluated for compounds (6, 7, 10a-d and 12a,b), while, compounds (10c,d and 12a,b) showed a high significant result relative to the normal control. According to the findings of this study, 2,3-dihydro-1H-pyrrolizine-5-carboxamide (9a) demonstrated high antioxidant (highest beta-carotene concentration (10.825 µg/ml)) and anti-inflammatory activity (EIP = 63.6 %) with lower ulcerogenicity (ulcer index 13.67), presenting it as a promising candidate for treating inflammatory diseases which are complicated by oxidative tissue damage. Furthermore, MOE software tools docking software was used to carry out the in silico studies. Docking study for the most active compounds showed that all compounds made three to four H-bond interactions in COX-2 active site adopting excellent docking scores.

Design and synthesis of new indole drug candidates to treat Alzheimer's disease and targeting neuro-inflammation using a multi-target-directed ligand (MTDL) strategy

A novel series of indole-based compounds was designed, synthesised, and evaluated as anti-Alzheimer’s and anti-neuroinflammatory agents. The designed compounds were in vitro evaluated for their AChE and BuChE inhibitory activities. The obtained results revealed that compound 3c had higher selectivity for AChE than BuChE, while, 4a, 4b, and 4d showed selectivity for BuChE over AChE. Compounds 5b, 6b, 7c, and 10b exerted dual AChE/BuChE inhibitory activities at nanomolar range. Compounds 5b and 6b had the ability to inhibit the self-induced Aβ amyloid aggregation. Different anti-inflammatory mediators (NO, COX-2, IL-1β, and TNF-α) were assessed for compounds 5b and 6b. Cytotoxic effect of 5b and 6b against human neuroblastoma (SH-SY5Y) and normal hepatic (THLE2) cell lines was screened in vitro. Molecular docking study inside rhAChE and hBuChE active sites, drug-likeness, and ADMET prediction were performed.

Design, synthesis, stereochemical determination, molecular docking study, in silico pre-ADMET prediction and anti-proliferative activities of indole-pyrimidine derivatives as Mcl-1 inhibitors

In this study, fourteen novel indole-pyrimidine hybrids were designed and synthesized. Their chemical structures were confirmed using different spectroscopic techniques (¹H NMR, ¹³C NMR, IR and mass). Their (E) stereochemical configuration was determined theoretically (MM2 property) and experimentally using 2D NMR technique (NOESY experiment). The prepared compounds were subjected to preliminary biological studies as Mcl-1 inhibitors. Most of the compounds exhibited good abilities for targeting Mcl-1 protein, especially, 7d, 7e, 7i and 7k (K_i = 11.19-15.21 nM). These derivatives were further evaluated against Bcl-XL and Bcl-2 proteins. Some compounds were found to have dual Mcl-1/Bcl-XL such as 7i, or Bcl-XL/Bcl-2 inhibitory activity as 7d. The most potent derivatives as Mcl-1 inhibitors were chosen as representative examples for determination of in-vitro anti-proliferative activity against PC-3, K-562 and MDA-MB-231 cell lines. They possessed excellent to good anti-proliferative activities. All of the synthesized compounds were docked into Mcl-1 active site. Drug-likeness properties and in silico pre-ADMET characters were also predicted.

Optimization of pyrazole-based compounds with 1,2,4-triazole-3-thiol moiety as selective COX-2 inhibitors cardioprotective drug candidates: Design, synthesis, cyclooxygenase inhibition, anti-inflammatory, ulcerogenicity, cardiovascular evaluation, and molecular modeling studies

The cardiovascular side effects associated with COX-2 selective drugs were the worst for coxibs leading to their withdrawal from the market a few years after their discovery. Therefore, the design of new series of pyrazole (4a,b 5a,b, 7a,b, 9a,b, 10a-h, and 11a-f) substituted with a triazole moiety as selective COX-2 inhibitors with cardioprotective effect was aimed in this paper. The target compounds were prepared and evaluated in-vitro against COX-1 and COX-2 enzymes. Compound 5-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-4H-1,2,4-triazole-3-thiol (7a) showed the highest selectivity towards COX-2 enzyme (S.I. = 27.56) and was the most active anti-inflammatory agent. Interestingly, its cardiovascular profile showed the cardiac biomarkers (ALP, AST, CK-MB, and LDH), as well as inflammatory cytokines named (TNF-α and IL-6) nearly similar to the control. Besides, a histopathological study of the heart muscle and the stomach was also included. The results confirmed that compound 7a has a more favorable cardio profile than celecoxib. Moreover, docking simulation for the most selective compounds 4b, 7a, 10e, 11c, and 11e inside COX-2 active site was performed to explain their binding mode. Finally, an ADME study was applied and proved the promising activity of the new compounds as a new oral anti-inflammatory agent. In conclusion, the newly developed compound 7a represents a potential selective COX-2 NSAID candidate with minimum cardiovascular risks.

Pyrazolo[3,4-d]pyrimidine-based dual EGFR T790M/HER2 inhibitors: Design, synthesis, structure-activity relationship and biological activity as potential antitumor and anticonvulsant agents

A new series of pyrazolo[3,4-d]pyrimidine/triazine hybrids 6a-r was designed as antitumor and anticonvulsant agents. All the prepared compounds were evaluated against colon (HCT-116), breast (MCF-7) and normal human fibroblast (WI38) cell lines. The most potent derivatives against HCT-116 and MCF-7 cells were 6o and 6q, with IC₅₀ = 4.80 and 6.50 nM, respectively, when compared to lapatinib, the reference drug (IC₅₀ = 12.00 and 21.00 nM, on HCT-116 and MCF-7, sequentially). All other derivatives exhibited good to moderate cytotoxic activity. Four compounds 6f, 6j, 6o and 6q were evaluated for their EGFR T790M/HER2 inhibitory activity. They revealed 81.81-65.70% and 86.66-54.49% inhibitory activity against EGFR T790M and HER2 in a sequent. The most potent derivatives 6o and 6q were further estimated for cell cycle analysis showing pre G1 apoptotic activity and cell growth arrest at G2/M phase. Apoptotic marker proteins expression levels (caspase-3/7/9, Bax and Bcl-2) were measured for 6o and 6q. They showed pro-apoptotic effect by increasing caspase-3/7/9 protein levels and Bax/Bcl-2 ratio. Moreover, anticonvulsant activity for the prepared compounds 6a-r were evaluated in vivo using lithium-pilocarpine mice model of Status Epilepticus. EEG changes where recorded and MDA, GSH, GABA and glutamate were measured in brain tissue of different groups. All tested compounds revealed variable anti-epileptic effects, the most potent compounds were 6b and 6m. Also 6d, 6e, 6h, 6i, 6k, 6l and 6n compounds exhibited good anti-seizure activity, while compound 6j showed the lower activity. The rest of compounds displayed a neutral activity.

2-Thiopyrimidine/chalcone hybrids: design, synthesis, ADMET prediction, and anticancer evaluation as STAT3/STAT5a inhibitors

A novel 2-thiopyrimidine/chalcone hybrid was designed, synthesised, and evaluated for their cytotoxic activities against three different cell lines, K-562, MCF-7, and HT-29. The most active cytotoxic derivatives were 9d, 9f, 9n, and 9p (IC50=0.77-1.74 µM, against K-562 cell line), 9a and 9r (IC50=1.37-3.56 µM against MCF-7 cell line), and 9a, 9l, and 9n (IC50=2.10 and 2.37 µM against HT-29 cell line). Compounds 9a, 9d, 9f, 9n, and 9r were further evaluated for their cytotoxicity against normal fibroblast cell line WI38. Moreover, STAT3 and STAT5a inhibitory activities were determined for the most active derivatives 9a, 9d, 9f, 9n, and 9r. Dual inhibitory activity was observed in compound 9n (IC50=113.31 and 50.75 µM, against STAT3 and STAT5a, respectively). Prediction of physicochemical properties, drug likeness score, pharmacokinetic and toxic properties was detected.

Design, synthesis, and biological evaluation of novel 1,2-diaryl-4-substituted-benzylidene-5(4H)-imidazolone derivatives as cytotoxic agents and COX-2/LOX inhibitors

A new series of 1,2-diaryl-4-substituted-benzylidene-5(4H)-imidazolone derivatives 4a-l was synthesized. Their structures were confirmed by different spectroscopic techniques (IR, ¹ H NMR, DEPT-Q NMR, and mass spectroscopy) and elemental analyses. Their cytotoxic activities in vitro were evaluated against breast, ovarian, and liver cancer cell lines and also normal human skin fibroblasts. Cyclooxygenase (COX)-1, COX-2 and lipoxygenase (LOX) inhibitory activities were measured. The synthesized compounds showed selectivity toward COX-2 rather than COX-1, and the IC₅₀ values (0.25-1.7 µM) were lower than that of indomethacin (IC₅₀  = 9.47 µM) and somewhat higher than that of celecoxib (IC₅₀  = 0.071 µM). The selectivity index for COX-2 of the oxazole derivative 4e (SI = 3.67) was nearly equal to that of celecoxib (SI = 3.66). For the LOX inhibitory activity, the new compounds showed IC₅₀ values of 0.02-74.03 µM, while the IC₅₀ of the reference zileuton was 0.83 µM. The most active compound 4c (4-chlorobenzoxazole derivative) was found to have dual COX-2/LOX activity. All the synthesized compounds were docked inside the active site of the COX-2 and LOX enzymes. They linked to COX-2 through the N atom of the azole scaffold, while CO of the oxazolone moiety was responsible for the binding to amino acids inside the LOX active site.

Novel tetrazole and cyanamide derivatives as inhibitors of cyclooxygenase-2 enzyme: design, synthesis, anti-inflammatory evaluation, ulcerogenic liability and docking study

Nineteen new compounds containing tetrazole and/or cyanamide moiety have been designed and synthesised. Their structures were confirmed using spectroscopic methods and elemental analyses. Anti-inflammatory activity for all the synthesised compounds was evaluated in vivo. The most active compounds 4c, 5a, 5d-f, 8a and b and 9a and b were further investigated for their ulcerogenic liability and analgesic activity. Pyrazoline derivatives 9b and 8b bearing trimethoxyphenyl part and SO₂NH₂ or SO₂Me pharmacophore showed equal or nearly the same ulcerogenic liability (UI: 0.5, 0.75, respectively), to celecoxib (UI: 0.50). Most of tested compounds showed potent central and/or peripheral analgesic activities. Histopathological investigations were done to evaluate test compounds effect on rat's gastric tissue. The obtained results were in consistent with the in vitro data on COX evaluation. Docking study was also done for all the target compounds inside COX-2-active site.