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, synthesis of novel chromene-based scaffolds targeting hepatocellular carcinoma: Cell cycle arrest, cytotoxic effect against resistant cancer cells, apoptosis induction, and c-Src inhibition.

New chromene derivatives were synthesized based on 4-(3,4-dimethoxy)-4H-chromene scaffold. All target compounds exhibited cytotoxic activity against HepG2 cells (IC50 = 2.40-141.22 µM). Chromens 5 and 9 showed superior cytotoxicity over staurosporine (IC50 = 18.27 µM) and vinblastine (IC50 = 5.20 µM). c-Src kinase inhibition assay of compounds 5 and 9 displayed the dominant c-Src inhibitory activity of 5 (IC50 = 0.184 µM) over 9 (IC50 = 0.288 µM). The safety of the most potent compound 5 against normal WI-38 cells was confirmed via its IC50 of 115.75 µM comparable with 5-FU (IC50 = 16.28 µM). Moreover, the promising chromene 5 displayed potent cytotoxicity against resistant HepG2 cells with IC50 of 26.03 µM comparable with 5-FU (IC50 = 42.68 µM). The most active chromene 5 arrested the HepG2 cell cycle at the S phase and induced a 29-fold increase in the total number of apoptotic cells indicating pre-G1 apoptosis. The ability of compound 5 to induce apoptosis was supported via elevation of caspase-3, caspase-7, caspase-9 and proapoptotic Bax protein levels in addition to downregulation of the antiapoptotic Bcl2 protein. Molecular docking studies of compound 5 showed good binding interaction pattern inside c-Src kinase enzyme active site.

New Sulfamethoxazole Derivatives as Selective Carbonic Anhydrase IX and XII Inhibitors: Design, Synthesis, Cytotoxic Activity and Molecular Modeling.

In this study new sulphamethoxazole derivatives (S1-S4, S6-S12, and S14-S22) were designed and synthesized and their structures were fully characterized and validated using NMR, mass, and IR spectroscopy, as well as elemental analyses. All new derivatives (S1-S22) were assayed against human carbonic anhydrase (hCAs IX and XII) for their inhibitory activities. hCAs IX and XII were chosen due to the fact that CAIX expression is recognized as a hypoxia marker with a poor prognosis in breast cancer. When compared to Dorzolamide HCl as a standard reference, derivatives S2, S3, S8, S9, and S15 had the most effective inhibition with low IC50 values. The active compounds were further evaluated against hCAs I and II inhibitory activity and compounds S8, S9 and S15 showed the least inhibitory effect compared to the reference standard, acetazolamide, indicating that their effect in normal cells is the lowest. Cell viability tests for the selected compounds were carried out on MCF7 (normoxia and hypoxia) and on the normal breast cell line (MCF10a) with Staurosporine as a standard. The results showed that compound S15 had a highly potent cytotoxic effect. Furthermore, cell cycle analysis results showed that compound S15 triggered cell cycle arrest and apoptosis in G1/S of MCF7 cancer cells. Finally, molecular docking was performed to point out the possible explanation for the vital structural features and key-interactions exerted by our ligands with hCAs IX and XII that might share additional designs and highlight possible leads for a hopeful anticancer agent. Consequently, sulphamethoxazole Derivative S15 could be the potential lead for emerging selective cytotoxic compounds directing h CAs IX and XII.

Design, synthesis, and pharmacological evaluation of novel and selective COX-2 inhibitors based on celecoxib scaffold supported with in vivo anti-inflammatory activity, ulcerogenic liability, ADME profiling and docking study.

Four new series of 1,2,4 triazole derivatives 4a,b 5a-d, 6a-f, and 7a,b possessing methylsulphonylphenyl moiety as COX-2 pharmacophore were designed and synthesized. The target compounds were prepared and evaluated in-vitro against COX-1 and COX-2 enzymes. Compounds 4a, 5b, 6a, and 7a showed the highest selectivity towards the COX-2 enzyme (S.I. = 8.64-14.58) in comparison to celecoxib (S.I. = . 6.44). Interestingly, compounds 4a, 6a, and 7a showed good anti-inflammatory activity with edema inhibition (54.17, 53.03, and 50.29 %, in order) relative to the reference drug celecoxib (49.60%) after 3 h. Additionally, these potent derivatives 4a, 5b, 6a and 7a were significantly less ulcerogenic (U.I. = 2.27-2.97) than both reference drugs celecoxib (U.I. = 2.99) and indomethacin (U.I. = 20.25). Besides, a histopathological study of the stomach was also included. Moreover, docking simulation for the most selective compounds 4a, 5b, 6a, and 7a 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 above findings reveal that newly developed compounds 4a, 6a, and 7a represent a potential selective COX-2 NSAID candidate with minimum gastrointestinal risks.

Antitrypanosomal activity of new semi-synthetic bergenin derivatives.

Bergenin and 11-O-(4'-O-methyl galloyl)-bergenin, previously isolated from Crassula capitella extract, were used as starting materials for the synthesis of eight derivatives; four derivatives 2a-2d were synthesized from bergenin through the formation of ester derivatives and four alkyl derivatives 4a-4d were synthesized from 11-O-(4'-O-methyl galloyl)-bergenin. The structures of the synthesized analogues were confirmed upon 1 H and 13 C NMR spectroscopic elucidation. Antileishmanial and antitrypanosomal activities of the synthesized derivatives were evaluated, compounds 11-O-(3',5' di-benzyl, 4'-O-methyl galloyl)-8,10-di-O-benzyl-bergenin (4c) and 11-O-(3',5'di-4-chlorobenzyl,4'-O-methyl galloyl)-8,10di-O-4-chlorobenzyl bergenin (4d) showed potent antitrypanosomal activity with IC50 values of 0.52 and 0.5 µM, respectively and IC90  values of 0.66 µM against T. brucei compared with IC50 and IC90 values of 21.7 and 50.3 µM for the positive control difluoromethylornithine.

Development of potential anticancer agents and apoptotic inducers based on 4-aryl-4H chromene scaffold: Design, synthesis, biological evaluation and insight on their proliferation inhibition mechanism.

An array of 4-aryl-2-amino-4H chromene derivatives were designed, synthesized, and evaluated for cytotoxic activity against four cancer cell lines and two non-cancerous cell lines. The most active candidates were further screened for their in vitro anticancer activity on NCI panel of 60 human cancer cell lines where compounds 2a, 2b, 4a-2, and 2e showed promising activity against various leukemia, non-small lung, renal, prostate, and breast cancer cell lines, particularly against NCI-H522 non-small lung cancer cell line (GI50 of 0.35-0.60 µM), MCF7 breast cancer cell line (GI50 of 0.34-0.59 µM), and MDA-MB-468 breast cancer cell line (GI50 of 0.23-0.40 µM). Compound 2b was the most potent against all leukemia and prostate cancer cell lines with GI50 values (0.29-0.60 µM). Compound 2b inhibited the proliferation of MCF-7 and HepG2 cells by inducing cell cycle arrest and apopotosis. 2b downregulated the mRNA abundance of BAX, Apaf-1 and caspase-3 and upregulated BCL-2. The activities of caspase-3 and caspase-9 were declined in MCF-7 and HepG2 cells treated with compound 2b. Compounds 2b and 4a-2 inhibited tubulin polymerization, with an IC50 values of 0.92 and 1.13 µM, respectively. These findings indicate that these synthesized compounds may represent potential drug candidates to inhibit the proliferation of different types of cancer cells.

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.

New indomethacin analogs as selective COX-2 inhibitors: Synthesis, COX-1/2 inhibitory activity, anti-inflammatory, ulcerogenicity, histopathological, and docking studies.

New indomethacin analogs 4a-g, 5, 6, 8a, and 8b were synthesized to overcome the nonselectivity and ulcer liability of indomethacin. All newly synthesized compounds were more potent against cyclooxygenase 2 (COX-2; IC50 value range: 0.09-0.4 µÐœ) as compared with celecoxib (IC50 = 0.89 µÐœ). Compounds 4a, 4b, 4d, 5, and 6 showed the highest COX-2 selectivity index (SI range = 4.07-6.33) as compared with indomethacin (SI = 1.14) and celecoxib (SI = 3.52). Additionally, 4a, 4b, 4d, 5, and 7 showed good anti-inflammatory activity with edema inhibition (79.36-88.8%), relative to celecoxib (78.96%) and indomethacin (90.43%), after 5 h. Also, ulcerogenic effects and histopathological examination were assessed for the most potent analogs, 4b, 4d, 5, and 6, to determine their safety. The results can shed light on indomethacin analog 5 as a remarkable anti-inflammatory lead compound with a good safety profile (ulcer index = 10.62) close to the nonulcerogenic drug celecoxib (ulcer index = 10.53) and better than indomethacin (ulcer index = 18.50). Docking studies were performed in the COX-2 active site for the most active compounds, to test their selectivity and to confirm their mechanism of action.

Sulfonamide-based 4-anilinoquinoline derivatives as novel dual Aurora kinase (AURKA/B) inhibitors: Synthesis, biological evaluation and in silico insights.

Aurora kinases (AURKs) were identified as promising druggable targets for targeted cancer therapy. Aiming at the development of novel chemotype of dual AURKA/B inhibitors, herein we report the design and synthesis of three series of 4-anilinoquinoline derivatives bearing a sulfonamide moiety (5a-d, 9a-d and 11a-d). The % inhibition of AURKA/B was determined for all target quinolines, then compounds showed more than 50% inhibition on either of the enzymes, were evaluated further for their IC50 on the corresponding enzyme. In particular, compound 9d displayed potent AURKA/B inhibitory activities with IC50 of 0.93 and 0.09 µM, respectively. Also, 9d emerged as the most efficient anti-proliferative analogue in the US-NCI anticancer assay toward the NCI 60 cell lines panel, with broad spectrum activity against different cell lines from diverse cancer subpanels. Docking studies, confirmed that, the sulfonamide SO2 oxygen was involved in a hydrogen bond with Lys162 and Lys122 in AURKA and AURKB, respectively, whereas, the sulfonamide NH could catch hydrogen bond interaction with the surrounding amino acid residues Lys141, Glu260, and Asn261 in AURKA and Lys101, Glu177, and Asp234 in AURKB. Furthermore, N1 nitrogen of the quinoline scaffold formed an essential hydrogen bond with the hinge region key amino acids Ala213 and Ala173 in AURKA and AURKB, respectively.

A multicomponent reaction to design antimalarial pyridyl-indole derivatives: Synthesis, biological activities and molecular docking.

Using fragment-based design strategy, new pyridyl-indole hybrids 4a-y and indole intermediates 3a-e were synthesized using multicomponent one pot reaction. The synthesized compounds were subjected to screening for antimalarial activity against chloroquine sensitive (D6) and chloroquine resistant (W2) strains of Plasmodium falciparum. Several compounds exhibited antimalarial activity with IC50 values in the range of 1.47-9.23 µM, and 1.16-7.66 µM, for D6 and W2 strains, respectively. Compounds 4a, 4k and 4u showed the highest selectivity index among all the tested compounds (S.I. ranged 3.8-10). Binding interactions between the active antimalarial compounds and the active site of quadruple mutant Plasmodium falciparum dihydrofolate reductase enzyme have been investigated using molecular docking analysis.

New pyrimidine-benzoxazole/benzimidazole hybrids: Synthesis, antioxidant, cytotoxic activity, in vitro cyclooxygenase and phospholipase A2-V inhibition.

To enhance the cytotoxicity of benzimidazole and/or benzoxazole core, the benzimidazole/benzoxazole azo-pyrimidine were synthesized through diazo-coupling of 3-aminophenybenzimidazole (6a) or 3-aminophenylbenzoxazole (6b) with diethyl malonate. The new azo-molanates 6a&b mixed with urea in sodium ethoxide to afford the benzimidazolo/benzoxazolopyrimidine 7a&b. The structure elucidation of new synthesized targets was proved using spectroscopic techniques NMR, IR and elemental analysis. The cytoxicity screening had been carried out against five cancer cell lines: prostate cancer (PC-3), lung cancer (A-549), breast cancer (MCF-7), pancreas cancer (PaCa-2) and colon cancer (HT-29). Furthermore, the antioxidant activity, phospholipase A2-V and cyclooxygenases inhibitory activities of the target compounds 7a&b were evaluated and the new compounds showed potent activity (cytotoxicity IC50 range from 4.3 to 9.2 µm, antioxidant activity from 40% to 80%, COXs or LOX inhibitory activity from 1.92 µM to 8.21 µM). The docking of 7a&b was made to confirm the mechanism of action.

Determination of flutamide and two major metabolites using HPLC-DAD and HPTLC methods.

Flutamide is a potential antineoplastic drug classified as an anti-androgen. It is a therapy for men with advanced prostate cancer, administered orally after which it undergoes extensively first pass metabolism in the liver with the production of several metabolites. These metabolites are predominantly excreted in urine. One of the important metabolites in plasma is 4-nitro-3-(trifluoromethyl)phenylamine (Flu-1), while the main metabolite in urine is 2-amino-5-nitro-4-(trifluoromethyl)phenol (Flu-3). In this work the two metabolites, Flu-1 and Flu-3, have been synthesized, and then structural confirmation has been carried out by HNMR analysis. Efforts were exerted to develop chromatographic methods for resolving Flutamide and its metabolites with the use of acceptable solvents without affecting the efficiency of the methods. The drug along with its metabolites were quantitatively analyzed in pure form, human urine, and plasma samples using two chromatographic methods, HPTLC and HPLC-DAD methods. FDA guidelines for bio-analytical method validation were followed and USP recommendations were used for analytical method validation. Interference from excipients has been tested by application of the methods to pharmaceutical tablets. No significant difference was found between the proposed methods and the official one when they were statistically compared at p value of 0.05%.

Design and synthesis of new coumarin hybrids and insight into their mode of antiproliferative action.

Molecular hybridization approach was used to synthesize three series of coumarin based hybrids by conglomerate a substituted chalcones, acrylohydrazides, and pyridines moieties with 8-methoxy coumarin. The hybrids showed significant cytotoxic activity against liver cancer Hep G2 and Leukemia K562 cell lines with IC50 values 0.49-3.96µM, comparable to the positive controls and exhibited weak activity against the normal cell line WI-38, thus indicating selectivity toward the tumor cells. Coumarin-chalcone hybrids 2a-c have demonstrated the most promising activity against both cancer cell lines with IC50 values of 0.65-2.02µM. Interestingly, the acrylohydrazide hybrid 4c showed the highest cytotoxic activity against the leukemia cell line (K562) with IC50 value of 0.49µM. All the investigated coumarin hybrids were able to increase the caspase-3 and caspase-9 proteins level expression relative to that of the untreated cells suggesting that coumarin hybrids-induced apoptosis was, in part, due to activation of caspases 3 and 9. Apoptosis was further confirmed with down-regulation of Bcl-2 and up-regulation of Bax protein expression level. Furthermore, cell cycle analysis of 2a and 4c showed apoptotic signals activation, as a consequence of arrest in G2/M phase. Results of our study can shed light on coumarin-based hybrids as promising anticancer leads.

Design, synthesis and biological screening of some novel celecoxib and etoricoxib analogs with promising COX-2 selectivity, anti-inflammatory activity and gastric safety profile.

Two new series of 4,6-diaryl-3-cyanopyridine 4a-r and 1,3,5-triaryl-2-pyrazolines 6a-f and were prepared. The new compounds were evaluated for their in vitro COX-2 selectivity and in vivo anti-inflammatory activity. Compounds 4o,r and 6d,f had moderate to high selectivity index (S.I.) compared to celecoxib (selectivity indexes of 4.5, 3.14, 4.79 and 3.21, respectively) and also, showed in vivo anti-inflammatory activity approximately equal to or higher than celecoxib (edema inhibition %=60.5, 64.5, 59.3 and 59.3, after 3h, respectively) and the effective anti-inflammatory doses were (ED50=10.1, 7.8, 8.46 and 10.7mg/kg respectively, celecoxib ED50=10.8mg/kg) and ulcerogenic liability were determined for these compounds which showed promising activity by being more potent than celecoxib with nearly negligible ulcerogenic liability compared to celecoxib (reduction in ulcerogenic liability versus celecoxib=85, 82, 74 and 67%, respectively).

Synthesis, anti-inflammatory, cyclooxygenases inhibitions assays and histopathological study of poly-substituted 1,3,5-triazines: Confirmation of regiospecific pyrazole cyclization by HMBC.

Three novel triazines series were prepared. These series are pyrazolines (4a and 4b), pyrazoles (6a, 6b and 8a-d) and isoxazoles (7a and 7b). Such series were designed as COX-2 inhibitors. All compounds were characterized by using spectroscopic methods and elemental analysis. Regarding COX-2, compounds 5b, 4a and 3b were the most active with IC50 in the range of 0.55-0.87 µM. Most of synthesized compounds were relatively more potent to celecoxib (0.78 µM), diclofenac (2.94 µM) and indomethacin (7.24 µM). A molecular modeling study was performed for the most active compounds. Histopathological evaluation also was done to estimate the safety of compounds. Finally, structure elucidation of pyrazole 8 was studied by 2D NMR.

Design, synthesis and biological screening of new 4-thiazolidinone derivatives with promising COX-2 selectivity, anti-inflammatory activity and gastric safety profile.

Two series of new thiazolidin-4-one derivatives 4a-c and 8a-e were designed and prepared. All the synthesized compounds were evaluated for their in vitro COX-2 selectivity and anti-inflammatory activity in vivo. Compounds 8c and 8d showed the best overall in vitro COX-2 selectivity (selectivity indexes of 4.56 and 5.68 respectively) and in vivo activities (edema inhibition %=61.8 and 67 after 3h, respectively) in comparison with the reference drug celecoxib (S.I.=7.29, edema inhibition %=60 after 3h). In addition, 8c and 8d were evaluated for their mean effective anti-inflammatory doses (ED50=27.7 and 18.1 µmol/kg respectively, celecoxib ED50=28.2 µmol/kg) and ulcerogenic liability (reduction in ulcerogenic potential versus celecoxib=85%, 92% respectively. Molecular docking studies were performed and the results were in agreement with that obtained from the in vitro COX inhibition assays.

1-(4-Methane(amino)sulfonylphenyl)-3-(4-substituted-phenyl)-5-(4-trifluoromethylphenyl)-1H-2-pyrazolines/pyrazoles as potential anti-inflammatory agents.

2-Pyrazolins 14a-l and pyrazoles 15a-l were designed as celecoxib analogs for the evaluation of their in vitro COX-1/COX-2 inhibitory activity and the in vivo anti-inflammatory activity. Compounds 14i, 15a, 15d and 15f were the most COX-2 selective derivatives (S.I.=5.93, 6.08, 5.03 and 5.27 respectively) while the pyrazoline derivatives 14g and 14i exhibited the highest AI activity (ED50=190.5 and 160.1µmol/kg po, respectively).

Synthesis and anti-inflammatory evaluation of new 1,3,5-triaryl-4,5-dihydro-1H-pyrazole derivatives possessing an aminosulphonyl pharmacophore.

A novel series of 2-pyrazoline derivatives 13a-l was synthesized via aldol condensation of 4-substituted acetophenones with appropriately substituted aldehydes followed by cyclization of the formed chalcones with 4-hydrazinobenzenesulfonamide hydrochloride. The chemical structures of the target pyrazoline derivatives were proved by means of IR, (1)H NMR, (13)C NMR, mass spectroscopy and elemental analyses data. All the synthesized compounds were evaluated for their cyclooxygenase selectivity, anti-inflammatory and ulcerogenic liability. While compounds 13e, 13h and 13i showed moderate COX-2 selectivity in vitro and good anti-inflammatory activity in vivo, compound 13i showed the highest anti-inflammatory activity that is very close in potency to the reference drug (celecoxib) with better gastric profile than celecoxib.

Synthesis, characterization and biological evaluation of novel 4'-fluoro-2'-hydroxy-chalcone derivatives as antioxidant, anti-inflammatory and analgesic agents.

In an effort to develop safe and potent anti-inflammatory agents, a series of novel 4'-fluoro-2'-hydroxychalcones 5a-d and their dihydropyrazole derivatives 6a-d was prepared. It was synthesized via aldol condensation of 4'-fluoro-2'-hydroxyacetophenone with appropriately substituted aldehydes followed by cyclization with hydrazine hydrate. All the synthesized compounds were evaluated for their antioxidant, anti-inflammatory, cyclooxygenase inhibition selectivity and analgesic activities. The dimethoxychalcone 5a and its dihydropyrazole derivative 6a showed the highest antioxidant activity, while the monomethoxychalcone 5d and its dihydropyrazole derivative 6d showed the highest analgesic and anti-inflammatory activities. It was also found that there is a close correlation between 4'-fluoro-2'-hydroxychalcones 5a-d and their dihydropyrazole derivatives 6a-d in the screened biological activities. To explain the correlation between the synthesized chalcones and their dihydropyrazole derivatives, especially for the anti-inflammatory activity, docking studies were performed.

Synthesis of novel chromene derivatives of expected antitumor activity.

Inhibition of tubulin polymerization is one of the important tactics in cancer therapy. Since 4-aryl-4H-chromene derivatives are found to be microtubule-binding agents via interfering with tubulin polymerization so we decide to concentrate our exploration efforts on the combination of this nucleus with 5-, 6-, and/or 7-memebered heterocyclic moieties in a novel series of compounds to explore the effect that might result from this combination. Ten novel compounds were selected for anticancer screening assay against MCF-7 breast cancer cell line in comparison to colchicine as positive control and most of them showed excellent activity.