Synthesis, biological evaluation, and molecular docking studies of 2,6-dinitro-4-(trifluoromethyl)phenoxysalicylaldoxime derivatives as novel antitubulin agents

A series of 2,6-dinitro-4-(trifluoromethyl)phenoxysalicylaldoxime derivatives (1h-20h) have been designed and synthesized, and their biological activities were also evaluated as potential antiproliferation and tubulin polymerization inhibitors. Among all the compounds, 2h showed the most potent activity in vitro, which inhibited the growth of MCF-7, Hep-G2 and A549 cell lines with IC(50) values of 0.70 ± 0.05, 0.68 ± 0.02 and 0.86 ± 0.05 μM, respectively. Compound 2h also exhibited significant tubulin polymerization inhibitory activity (IC(50)=3.06 ± 0.05 μM). The result of flow cytometry (FCM) demonstrated that compound 2h induced cell apoptosis. Docking simulation was performed to insert compound 2h into the crystal structure of tubulin at colchicine binding site to determine the probable binding model. Based on the preliminary results, compound 2h with potent inhibitory activity in tumor growth may be a potential anticancer agent.     

Novel 1H-imidazol-2-amine derivatives as potent and orally active vascular adhesion protein-1 (VAP-1) inhibitors for diabetic macular edema treatment

Novel thiazole derivatives were synthesized and evaluated as vascular adhesion protein-1 (VAP-1) inhibitors. Although we previously identified a compound (2) with potent VAP-1 inhibitory activity in rats, the human activity was relatively weak. Here, to improve the human VAP-1 inhibitory activity of compound 2, we first evaluated the structure–activity relationships of guanidine bioisosteres as simple small molecules and identified a 1H-benzimidazol-2-amine (5) with potent activity compared to phenylguanidine (1). Based on the structure of compound 5, we synthesized a highly potent VAP-1 inhibitor (37b; human IC₅₀ = 0.019 μM, rat IC₅₀ = 0.0051 μM). Orally administered compound 37b also markedly inhibited ocular permeability in streptozotocin-induced diabetic rats after oral administration, suggesting it is a promising compound for the treatment of diabetic macular edema.     

Effect of N,alpha-tosyl-L-phenylalanine chloromethyl ketone on measles virus P and M polypeptides

Treatment of measles virus-infected cells with 1 mM N,alpha-tosyl-L-phenylalanine chloromethyl ketone (TPCK) was observed to change the polyacrylamide gel migration of viral polypeptides P and M. Untreated cells contained P as a mixture of P1 (70,000 daltons) and P2 (65,000 daltons) and M as a 38,000-dalton band M1 and a slightly smaller band, M2. TPCK treatment resulted in conversion of P largely to the 65,000-dalton band and of M to M1 and a slightly slower-migrating band. This effect could also be demonstrated by treating homogenates of infected cells with TPCK, and the evidence suggests that the compound reacts directly with the viral P and M polypeptides and thereby changes their gel migration. TPCK also inhibited measles virus-associated protein kinase, and treatment of virion preparations with the compound resulted in a loss of infectivity; however, it was not possible to directly correlate the inhibitory effect on these two biological functions with the change seen in polypeptides P and M.     

Identification of 2(1H)-pyrimidinones as potential EGFR T790M inhibitors for the treatment of gefitinib-resistant non-small cell lung cancer

A new class of 2(1H)-pyrimidinone derivatives was identified as potential EGFR T790M inhibitors against TKI-resistant NSCLC. These novel compounds inhibited the EGFR T790M kinase activity at concentrations in the range of 85.3 to 519.9 nM. In particular, compound 7e exhibited the strongest activity against both EGFR^WT (IC₅₀ = 96.9 nM) and EGFR^T790M (IC₅₀ = 85.3 nM) kinases in the cells. Compared with inhibitor 7e, compound 7b displayed enhanced antiproliferative activity against gefitinib-resistant H1975 cells harboring the EGFR T790M mutation. In addition, compound 7b also has low toxicity against the normal human liver cells LO2, with an IC₅₀ of 11.1 µM. Moreover, both the AO/EB and DAPI staining assays also demonstrated the inhibitory efficacy of 7b against the resistant H1975 cells. This contribution provides a new scaffold 2(1H)-pyrimidinone as potential EGFR T790M inhibitor against drug-resistant NSCLC.     

Design, synthesis and biological evaluation of pyrazolyl-thiazolinone derivatives as potential EGFR and HER-2 kinase inhibitors

A series of pyrazolyl-thiazolinone derivatives (E1-E36) have been designed and synthesized and their biological activities were also evaluated as potential EGFR and HER-2 kinase inhibitors. Thirty-four of the 36 compounds were reported for the first time. Among them, compound 2-(5-(4-bromophenyl)-3-p-tolyl-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one (E28) displayed the most potent inhibitory activity (IC(50)=0.24μM for EGFR and IC(50)=1.07μM for HER-2). Antiproliferative assay results indicated that compound E28 owned high antiproliferative activity against MCF-7, B16-F10 and HCT-116 in vitro, with IC(50) value of 0.30, 0.54, and 0.70μM, respectively. Docking simulation was further performed to position compound E28 into the EGFR active site to determine the probable binding model. Based on the preliminary results, compound E28 with potent inhibitory activity in tumor growth would be a potential anticancer agent.     

Synthesis, biological evaluation, and molecular docking studies of 1,3,4-thiadiazol-2-amide derivatives as novel anticancer agents

A series of 1,3,4-thiadiazol-2-amide derivatives (5a-5y) have been designed and synthesized, and their biological activities were also evaluated as potential antiproliferation and FAK inhibitors. Among all the compounds, 5h showed the most potent activity in vitro, which inhibited the growth of MCF-7 and B16-F10 cell lines with IC(50) values of 0.45 and 0.31 μM, respectively. Compound 5h also exhibited significant FAK inhibitory activity (IC(50)=5.32 μM). Docking simulation was performed to position compound 5h into the FAK structure active site to determine the probable binding model. The results of antiproliferative and Western-blot assay demonstrated that compound 5h possessed good antiproliferative activity. Therefore, compound 5h with potent FAK inhibitory activity may be a potential anticancer agent.     

Peach (Prunus persica) fruit ripening: aminoethoxyvinylglycine (AVG) and exogenous polyamines affect ethylene emission and flesh firmness

The effect of various concentrations of aminoethoxyvinylglycine (AVG; 0.32 and 1.28 m M ), an ethylene biosynthesis inhibitor, and of the polyamines putrescine (10 m M ), spermidine (0.1, 1 and 5 m M ) and spermine (2 m M ) on peach ( Prunus persica L. Batsch cv. Redhaven) fruit ripening was evaluated under field conditions. Treatments were performed 19 (polyamines) and 8 (AVG) days before harvest. Fruit growth (diameter, fresh and dry weight), flesh firmness, soluble solids content and ethylene emission were determined on treated and untreated (controls) fruits. Moreover, endogenous polyamine content and S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.21) activity were determined to check for a possible competition between polyamines and ethylene for their common precursor S-adenosylmethionine (SAM). Both treatments strongly inhibited ethylene emission and delayed flesh softening. On a biochemical level, AVG and exogenous polyamines both reduced the free-to-conjugate ratio of endogenous polyamines, and transiently altered SAMDC activity. The possible use of these compounds to control fruit ripening is discussed also in the light of their rejuvenating effect on peach fruits.     

Phosphoramidate derivatives of acyclovir: Synthesis and antiviral activity in HIV-1 and HSV-1 models in vitro

The antiviral activity against HIV and HSV and the chemical stability of ACV phosphoramidate derivatives were studied. The phosphoramidates of ACV demonstrated moderate activity. The best compound appeared to be 9-(2-hydroxymethyl)guanine phosphoromonomorpholidate (7), which inhibited virus replication in pseudo-HIV-1 particles by 50% at 50 μM. It also inhibited replication of wild-type HSV-1 (9.7 μM) as well as an acyclovir-resistant strain (25 μM). None of the synthesised compounds showed any cytotoxicity.     

Design, synthesis and biological evaluation of pyridine acyl sulfonamide derivatives as novel COX-2 inhibitors

A series of pyridine acyl sulfonamide derivatives (1-24) have been designed and synthesized and their biological activities were also evaluated as potential cyclooxygenase-2 (COX-2) inhibitors. Among all the compounds, compound 23 displayed the most potent COX-2 inhibitory activity with an IC(50) of 0.8 μM. Antitumor and anti-inflammatory assays indicated that compound 23 owned high antiproliferative activity against B16-F10, HepG2 and MCF-7 cancer cell lines as well as COX-2-derived prostaglandin E(2) (PGE(2)) inhibitory activity of murine macrophage RAW 264.7 cell line with IC(50) values of 2.8, 1.2, 1.8 and 0.15 μM, respectively. Docking simulation was performed to position compound 23 into the COX-2 active site to determine the probable binding model.     

Design,synthesis and biological evaluation of novel pteridinone derivatives possessing a hydrazone moiety as potent PLK1 inhibitors

A series of novel pteridinone derivatives possessing a hydrazone moiety were designed, synthesized and evaluated for their biological activity. Most of the synthesized compounds demonstrated moderate to excellent activity against A549, HCT116 and PC-3 cancer cell lines. In particular, compound L₁₉ exhibited the most potent antiproliferative effects on three cell lines with IC₅₀ values of 3.23 μM, 4.36 μM and 8.20 μM, respectively. In kinase assays, the compound L₁₉ also showed potent inhibition activity toward PLK1 with % inhibition values of 75.1. Further mechanism studies revealed that compound L₁₉ significantly inhibited proliferation of HCT-116 cell lines, induced a great decrease in mitochondrial membrane potential resulting in apoptosis of cancer cells, inhibited the migration of tumor cells, and arrested G1 phase of HCT116 cells.     

Anti-tumour activity of 4-(4-fluorophenyl)amino-5,6,7-trimethoxyquinazoline against tumour cells in vitro

In order to create novel, potent and selective anti-cancer agents, the action of 4-(4-fluorophenyl)amino-5,6,7-trimethoxyquinazoline (compound 1018) on 10 different kinds of tumour cells were assayed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide]. It possesses a broad spectrum of anti-cancer activity. The mechanism of action of 4-(4-fluorophenyl)amino-5,6,7-trimethoxyquinazoline (hereafter referred to as compound 1018) against tumour cells was studied in androgen-independent prostate cancer PC-3 cells by microscopic observation, LDH (lactate dehydrogenase) release assay and Western blotting. Its activity was dose-dependent, with an IC50 of 13.0±1.4 μM after 72 h treatment. Microscopy and LDH release assay indicated that the effect was through anti-proliferation rather than cytotoxicity. Western blot analysis also showed that treatment of cells with 50 μM compound 1018 for 30 min almost completely inhibited EGF (epidermal growth factor)-induced phosphorylation of ERK1/2 (extracellular-signal-regulated kinase 1/2), which suggests that its anti-proliferative effect is largely associated due to ERK1/2 activation being inhibited. Thus compound 1018 is a potential anti-cancer agent.     

Synthesis, biological evaluation, and molecular docking studies of benzyl, alkyl and glycosyl [2-(arylamino)-4,4-dimethyl-6-oxo-cyclohex-1-ene]carbodithioates, as potential immunomodulatory and immunosuppressive agents

The immunomodulating properties of functionalized [2-(arylamino)-4,4-dimethyl-6-oxo-cyclohex-1-ene] carbodithioates and 6,6-dimethyl-4-(2-(propan-2-ylidene)hydrazinyl)-6,7-dihydro-2H-indazole-3(5H)-thione compounds have been investigated. Four of them, 13, 18, 19 and 20 inhibited PBMC proliferation induced by phytohemagglutinin (PHA) in a dose dependent manner with an IC(50) of ≤ 20 μM. The Th-1 cytokine, interleukin-2 (IL-2) in PHA/PMA-stimulated peripheral blood mononuclear cells (PBMCs) is significantly inhibited by 13, 19 and 20 with an IC(50) of 8.4 ± 0.4, 5.34 ± 0.15 and 4.9 ± 0.7 μM, respectively. They also inhibited the PMA/lipopolysaccharide-induced proinflammatory cytokines, IL-1β and TNF-α production in human monocytic leukemia cells (THP-1), by 86%, 46% and 59.2% for IL-1β and by 83.8%, 48.2% and 58.7% for TNF-α, respectively. Only 20 showed significant suppressive activity against the phagocyte oxidative burst in a dose dependent manner, with an IC(50) of 23.8 μM. LPS-induced nitrites in mouse macrophages were found to be inhibited by compounds 6, 8, 13-15 and 19 with an IC(50), which range between 7.7 and 63 μM. The cytotoxicity for the active compounds was also studied on Rat Wistar Hepatocyte cell line, CC1 and the Mouse Fibroblast cell line 3T3 NIH in the presence of compounds using a standard MTT assay. Furthermore, structural-activity relationship using automated docking software revealed that active compounds 7, 13 and 19, adapted the same binding mode, however the most active compound 20 is found deeply inserted within the ligand binding site of IL-2, as multiple hydrophobic and hydrophilic key interactions stabilize the compound inside the binding site, thus contributing higher activity.     

Design,Synthesis, and Molecular Docking of Some Novel Tacrine Based Cyclopentapyranopyridine- and Tetrahydropyranoquinoline-Kojic Acid Derivatives as Anti-Acetylcholinesterase Agents

A novel series of tacrine based cyclopentapyranopyridine- and tetrahydropyranoquinoline-kojic acid derivatives were designed, synthesized, and evaluated as anti-cholinesterase agents. The chemical structures of all target compounds were characterized by ¹H-NMR, ¹³C-NMR, and elemental analyses. The synthesized compounds mostly inhibited acetylcholinesterase enzyme (AChE) with IC₅₀ values of 4.18–48.71 μM rather than butyrylcholinesterase enzyme (BChE) with IC₅₀ values of >100 μM. Among them, cyclopentapyranopyridine-kojic acid derivatives showed slightly better AChE inhibitory activity compared to tetrahydropyranoquinoline-kojic acid. The compound 10-amino-2-(hydroxymethyl)-11-(4-isopropylphenyl)-7,8,9,11-tetrahydro-4H-cyclopenta[b]pyrano[2′,3′ : 5,6]pyrano[3,2-e]pyridin-4-one ( 6f ) bearing 4-isopropylphenyl moiety and cyclopentane ring exhibited the highest anti-AChE activity with IC₅₀ value of 4.18 μM. The kinetic study indicated that the compound 6f acts as a mixed inhibitor and the molecular docking studies also illustrated that the compound 6f binds to both the catalytic site (CS) and peripheral anionic site (PAS) of AChE. The compound 6f showed moderate neuroprotective properties against H₂O₂-induced cytotoxicity in PC12 cells. The theoretical ADME study also predicted good drug-likeness for the compound 6f . Based on these results, the compound 6f seems to be a very promising AChE inhibitor for the treatment of Alzheimer's disease.     

Design and synthesis of benzo[c,d]indolone-pyrrolobenzodiazepine conjugates as potential anticancer agents

A series of benzo[c,d]indol-2(1H)one-PBD conjugates (11a-l) have been designed and synthesized as potential anticancer agents. These compounds were prepared by linking the C8-position of DC-81 with a benzo[c,d]indol-2(1H)one moiety through different alkane spacers in good yields and confirmed by (1)H NMR, mass and HRMS data. The DNA binding ability of these conjugates was evaluated by thermal denaturation studies and interestingly, compound 11l showed enhanced DNA binding ability. These compounds were also evaluated for their anticancer activity in selected human cancer cell lines of lung, skin, colon and prostate by using MTT assay method. These new conjugates showed promising anticancer activity with IC(50) values ranging from 1.05 to 36.49 μM. Moreover, cell cycle arrest in SubG1 phase was observed upon treatment of A549 cells with 1 and 2 μM (IC(50)) concentrations of compound 11l and it induced apoptosis. This is confirmed by Annexin V-FITC, Hoechst staining, caspase-3 activity as well as DNA fragmentation analysis.     

Design,Synthesis, and Evaluation of Chalcone Derivatives as Multifunctional Agents against Alzheimer's Disease

Fifteen chalcone derivatives 3a – 3o were synthesized, and evaluated as multifunctional agents against Alzheimer's disease. In vitro studies revealed that these compounds inhibited self-induced Aβ_1-42 aggregation effectively ranged from 45.9–94.5 % at 20 μM, and acted as potential antioxidants. Their structure-activity relationships were summarized. In particular, (2E)-3-[4-(dimethylamino)phenyl]-1-(pyridin-2-yl)prop-2-en-1-one ( 3g ) exhibited an excellent inhibitory activity of 94.5 % at 20 μM, and it could disassemble the self-induced Aβ_1-42 aggregation fibrils with ratio of 57.1 % at 20 μM concentration. In addition, compound 3g displayed good chelating ability for Cu²⁺, and could effectively inhibit and disaggregate Cu²⁺-induced Aβ aggregation. Moreover, compound 3g exerted low cytotoxicity, significantly reversed Aβ_1-42-induced SH-SY5Y cell damage. More importantly, compound 3g remarkably ameliorated scopolamine-induced memory impairment in mice. In summary, all the results revealed compound 3g was a potential multifunctional agent for AD therapy.     

Comparative Physiology of Dimethyl Sulfide Production by Dimethylsulfoniopropionate Lyase in Pseudomonas doudoroffii and Alcaligenes sp. Strain M3A

Dimethylsulfoniopropionate (DMSP) lyase enzymatically cleaves DMSP, an algal metabolite, to produce acrylate, a proton, and dimethyl sulfide (DMS), the most abundant volatile sulfur compound emitted from oceans. The physiology of DMS production by DMSP lyase was studied in vivo in an Alcaligenes-like organism, strain M3A, a salt marsh bacterial isolate, and in a marine strain, Pseudomonas doudoroffii. Enzymes from both strains were induced at optimum rates by 1 mM DMSP and vigorous aeration. P. doudoroffii was very sensitive to continued aeration and lost activity rapidly; the enzyme was more stable when aeration ceased. In addition to DMSP, acrylate and several of its analogs acted as inducers of DMSP lyase in Alcaligenes sp. strain M3A but not in P. doudoroffii. Turnover of DMSP by P. doudoroffii was enhanced by 3.5% NaCl or seawater, whereas the Alcaligenes sp. strain M3A enzyme was not salt dependent and salt did not greatly affect its activity. The pH profile showed two peaks of DMSP lyase activity (6.5 and 8.8) for Alcaligenes sp. strain M3A and a single peak at pH 8 for P. doudoroffii. Enzyme activity in both organisms was inhibited by methyl-3-mercaptopropionate and homocysteine. Cyanide, azide and p-chloromercuribenzoate inhibited only the P. doudoroffii DMSP lyase. The apparent K(infm) values for DMSP for cell cultures of Alcaligenes sp. strain M3A and P. doudoroffii were ca. 2 mM and <20 (mu)M, respectively. The differences in the physiology of DMSP metabolism in these two bacterial isolates may enable them to exist in diverse ecological niches.     

Characterization of inhibition of M2 ion channel activity by BL-1743, an inhibitor of influenza A virus.

The influenza A virus M2 integral membrane protein has ion channel activity that can be inhibited by the antiviral drug amantadine. Recently, a spirene-containing compound, BL-1743 (2-[3-azaspiro (5,5)undecanol]-2-imidazoline), that inhibits influenza virus growth was identified (S. Kurtz, G. Lao, K. M. Hahnenberger, C. Brooks, O. Gecha, K. Ingalls, K.-I. Numata, and M. Krystal, Antimicrob. Agents Chemother. 39:2204-2209, 1995). We have examined the ability of BL-1743 to inhibit the M2 ion channel when expressed in oocytes of Xenopus laevis. BL-1743 inhibition is complete as far as can be measured by electrophysiological methods and is reversible, with a reverse reaction rate constant of 4.0 x 10(-3) s(-1). In contrast, amantadine inhibition is irreversible within the time frame of the experiment. However, BL-1743 inhibition and amantadine inhibition have similar properties. The majority of isolated influenza viruses resistant to BL-1743 are also amantadine resistant. In addition, all known amino acid changes which result in amantadine resistance also confer BL-1743 resistance. However, one BL-1743-resistant virus isolated, designated M2-I35T, contained the change Ile-35-->Thr. This virus is >70-fold more resistant to BL-1743 and only 10-fold more resistant to amantadine than the wild-type virus. When the ion channel activity of M2-I35T was examined in oocytes, it was found that M2-I35T is BL-1743 resistant but is reversibly inhibited by amantadine. These findings suggest that these two drugs interact differently with the M2 protein transmembrane pore region.     

Synthesis of tetracyclic oxindoles and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity

A series of tetracyclic oxindole derivatives was synthesized by asymmetric 1, 3-dipole reaction in 2–4 steps in 57–86% overall yields. These compounds were evaluated for α-glucosidase inhibitory and glucose consumption-promoting activity in vitro. Compound 4l competitively and reversibly inhibited α-glucosidase (IC₅₀ = 3.64 μM) with activity 14-fold higher than that of acarbose. Docking analysis substantiated these findings. In addition, compound 4l exhibited significant glucose consumption promoting activity at 1 μM.     

The effect of selected arachidonic acid metabolites on natural killer cell activity

The effect of arachidonic acid (AA) metabolites of lipoxygenase(s) was evaluated on natural killer (NK) cell activity in Fischer F344 rat splenic lymphocytes and compared with prostaglandin E2 (PGE2), a known inhibitor of NK cell lytic activity. It was observed that 5(S),12(S)-dihydroxy-6,10-trans-8,14-cis-eicosatetraenoic acid (5(S),12(S)-diHETE, EZEZ) inhibited NK cell activity to a degree comparable to the inhibitory effects of PGE2. This compound maximally inhibited NK cell activity at concentrations of 10(-6) and 10(-8) M. PGE2 and 5(S),12(S)-diHETE (EZEZ) inhibited NK activity to an identical degree at all concentrations and effector:target (E:T) cell ratios tested. Of the other lipoxygenase pathway metabolites screened, 8(S),15(S)-all trans-diHETE and 8(S),15(S)-diHETE (EZEZ) also inhibited NK activity, but only at 10(-6) M and a 50:1 E:T cell ratio. These findings provide further evidence that the lipoxygenase and cyclooxygenase pathways produce metabolites which can modulate NK cell function, and that 5(S),12(S)-diHETE (EZEZ), which has not been previously tested for effects on NK cells, may have a significant immunoregulatory role.