Journal: Archiv der Pharmazie
A new scaffold of hydrazothiazoles has been designed as monoamine oxidase (MAO) inhibitors combining the hydrazine moiety of iproniazid and the thiazole nucleus of glitazones, a class of peroxisome proliferator-activated receptor (PPAR)γ agonists recently co-crystallized with human MAO-B. The resulting derivatives were synthesized and assayed to evaluate their in vitro activity against both the A and B isoforms of hMAO. All compounds were shown to be selective hMAO-B inhibitors with IC(50) values in the low micromolar/high nanomolar range. Such results suggest that the hydrazothiazole scaffold could be considered as an interesting pharmacophore for the future design of new lead compounds as coadjuvants for the treatment of neurodegenerative diseases.
In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structure-activity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC(50) = 69.3 µM) and Leishmania brasiliensis (IC(50) = 59.4 µM) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC(50) = 99.9 µM for L. amazonensis and IC(50) = 90.5 µM for L. braziliensis) and 3 (IC(50) = 122.9 µM for L. amazonensis and IC(50) = 109.8 µM for L. brasiliensis) were less active than dillapiole (1). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues.
In accordance with our antiviral drug development attempt, acylhydrazone derivatives bearing amino acid side chains were synthesized for the evaluation of their antiviral activity against various types of viruses. Among these compounds, 8(S) , 11(S) , and 12(S) showed anti-HIV-1 activity with a 50% inhibitory concentration (IC(50) ) = 123.8 µM (selectivity index, SI > 3), IC(50) = 12.1 µM (SI > 29), IC(50) = 17.4 µM (SI > 19), respectively. Enantiomers 8® , 11® , and 12® were inactive against the HIV-1 strain III(B) . Hydrazones 8(S) , 11(S) , and 12(S) which were active against HIV-1 wild type showed no inhibition against a double mutant NNRTI-resistant strain (K103N;Y181C). Molecular docking calculations of R- and S-enantiomers of 8, 11, and 12 were performed using the hydrazone-bound novel site of HIV-1 RT.
The oncoprotein cytotoxic associated gene A (CagA) of Helicobacter pylori plays a pivotal role in the development of gastric cancer, so it has been an important target for anti-H. pylori drugs. Conventional drugs are currently being implemented against H. pylori. The inhibitory role of plant metabolites like curcumin against H. pylori is still a major scientific challenge. Curcumin may represent a novel promising drug against H. pylori infection without producing side effects. In the present study, a comparative analysis between curcumin and conventional drugs (clarithromycin, amoxicillin, pantoprazole, and metronidazole) was carried out using databases to investigate the potential of curcumin against H. pylori targeting the CagA oncoprotein. Curcumin was filtered using Lipinski’s rule of five and the druglikeness property for evaluation of pharmacological properties. Subsequently, molecular docking was employed to determine the binding affinities of curcumin and conventional drugs to the CagA oncoprotein. According to the results obtained from FireDock, the binding energy of curcumin was higher than those of amoxicillin, pantoprazole, and metronidazole, except for clarithromycin, which had the highest binding energy. Accordingly, curcumin may become a promising lead compound against CagA+ H. pylori infection.
(Arylalkyl)azoles are a class of antiepileptic compounds including nafimidone, denzimol, and loreclezole (LRZ). Nafimidone and denzimol are thought to inhibit voltage-gated sodium channels (VGSCs) and enhance γ-aminobutyric acid (GABA)-mediated response. LRZ, a positive allosteric modulator of A-type GABA receptors (GABAA Rs), was reported to be sensitive to Asn265 of the β2/β3 subunit. Here, we report new N-[1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene]hydroxylamine esters showing anticonvulsant activity in animal models, including the 6-Hz psychomotor seizure test, a model for therapy-resistant partial seizure. We performed molecular docking studies for our active compounds using GABAA R and VGSC homology models. They predicted high affinity to the benzodiazepine binding site of GABAA R in line with the experimental results. Also, the binding mode and interactions of LRZ in its putative allosteric binding site of GABAA R is elucidated.
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 CO of the oxazolone moiety was responsible for the binding to amino acids inside the LOX active site.
New therapeutics are urgently needed to fight tuberculosis and mycobacteria-related diseases that are a major health hazard especially in poor countries. Natural products have been the source of important antitubercular drugs in the past and still need to receive attention as a potent reservoir of chemical structures. Fifteen known and two new (+)-usnic acid (a benzofurandione formerly isolated from lichens) enamines and hydrazones are here described and tested against sensitive and multidrug-resistant strains of mycobacteria. Among several (+)-usnic acid conjugates, PS14 and PS18 showed potent activity against both susceptible and resistant Mycobacterium tuberculosis strains (MIC values of 1-32 and 2-32 mg/L, respectively) comparable with MIC of other antitubercular drugs already in use for tuberculosis treatment.
A new series of quinazolinone hybrid molecules containing coumarin, furan, 1,2,4-triazole and 1,2,4-thiadiazole rings was designed, synthesized, and screened for their urease inhibition activities. All newly synthesized compounds showed outstanding urease inhibitory potentials with IC50 values ranging between 1.26 ± 0.07 and 7.35 ± 0.31 μg/mL. Among the series, coumarin derivatives (10a-d) exhibited the best inhibitory effect against urease in the range of IC50 = 1.26 ± 0.07 to 1.82 ± 0.10 μg/mL, when compared to standard urease inhibitors such as acetohydroxamic acid and thiourea (IC50 = 21.05 ± 0.96 and 15.08 ± 0.71 μg/mL, respectively). Molecular docking studies were also performed to analyze the binding mode of compound 10b, and supported the experimental results.
Triple-negative breast cancer (TNBC) is a complex and aggressive subtype of breast cancer characterized by high morbidity and mortality. In the absence of targeted therapy, only chemotherapy is available in this case of cancer. The current study investigated the antitumor effect of new pyridazin-3(2H)-one derivatives on the human TNBC cell line, MD-MB-468. The in vitro cytotoxic activities were investigated using the tetrazolium-based MTT assay. Lipid peroxidation, H2 O2 content, and the specific activities of antioxidant enzymes were also determined. Two molecules, 6f and 7h, were found to be selectively highly active against tumor cells with IC50 values of 3.12 and 4.9 µM, respectively. Furthermore, cells exposed to 6f showed a significant increase in H2 O2 and lipid peroxidation levels, accompanied by a decrease in the enzyme activities of glutathione reductase (GR) and thioredoxin reductase (TrxR). The cytotoxicity of the compound 6f may improve the therapeutic efficacy of the current treatment for TNBC via the inhibition of GR and TrxR activities.
Rapamycin is an mTOR allosteric inhibitor with multiple functions such as immunosuppressive, anticancer, and lifespan prolonging activities. Its C-43 semi-synthetic derivatives temsirolimus and everolimus have been used as mTOR targeting anticancer drugs in the clinic. Following our previous research on antitumor rapalogs modified on the C-43 position, 13 novel rapamycin triazole hybrids (6a-g, 7a-f) were designed and synthesized on the C-28 position of rapamycin via Huisgen’s reaction. Anticancer assays indicated that the targeted derivatives containing phenyl and 4-methylphenyl groups showed an obvious raise in anticancer activity. On the contrary, the compounds with methoxyl, amine, and halogen groups on the benzene ring displayed lower anticancer activity. Compound 6c, as the most active compound, showed a stronger inhibition effect as compared with rapamycin for almost all of the tested cell lines (p < 0.01), except PC-3. Meanwhile, the effect of 6c on inducing apoptosis and cell cycle arrest in A549 cells was more powerful than that of rapamycin. In addition, 6c inhibited the phosphorylation of mTOR and its downstream key kinases 4EBP1 and p70S6K1 in A549 cells, indicating that 6c also effectively inhibits the mTORC1 signaling pathway as rapamycin. On the basis of these findings, 6c may have the potential to be developed as a new mTOR inhibitor against specific cancers.