Synthesis, antimicrobial, anti-biofilm evaluation, and molecular modelling study of new chalcone linked amines derivatives.

A series of amide chalcones conjugated with different secondary amines were synthesised and characterised by different spectroscopic techniques 1H NMR, 13C NMR, and ESI-MS. They were screened for in vitro antibacterial activity. Compounds 36, 37, 38, 42, and 44 are the most active among the synthesised series exhibiting MIC value of 2.0-10.0 µg/ml against different bacterial strains. Compound 36 was equipotent to the standard drug Ampicillin displaying MBC value of 2.0 µg/ml against the bacterial strain Staphylococcus aureus. The products were screened for anti-biofilm activity. Compounds 36, 37, and 38 exhibited promising anti-biofilm activity with IC50 value ranges from 2.4 to 8.6 µg. Molecular modelling was performed suggesting parameters of signalling anti-biofilm mechanism. AspB327 HisB340 (arene-arene interaction) and IleB328 amino acid residues seemed of higher importance to inhibit c-di-GMP. Hydrophobicity may be crucial for activity. ADME calculations suggested that compounds 36, 37, and 38 could be used as good orally absorbed anti-biofilm agents.

Synthesis, biological evaluation and molecular modeling study of some new methoxylated 2-benzylthio-quinazoline-4(3H)-ones as nonclassical antifolates.

A new series of 2,3,6-substituted-quinazolin-4-ones was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 28 and 61 proved to be active DHFR inhibitors with IC50 0.02 and 0.01µM, respectively. Molecular modeling studies concluded that recognition with the key amino acid Phe34 is essential for binding and hence DHFR inhibition. Compounds 34, 56 and 66 showed broad spectrum antimicrobial activity comparable to Gentamicin and Ciprofloxacin. Compounds 40 and 64 showed broad spectrum antitumor activity toward several tumor cell lines and proved to be 10 fold more active than 5-FU, with GI50 MG-MID values of 2.2 and 2.4µM, respectively.

Synthesis, biological evaluation and molecular modeling study of some new thiazolodiazepine analogs as CNS active agents.

New derivatives of ethyl 8-oxo-5,6,7,8-tetrahydro-thiazolo[3,2-a][1,3]diazepin-3-carboxylate (HIE-124, 3), were synthesized as continuation to our previous patented efforts. Compounds 15 and 20 showed marginal hypnotic potency compared to 3. Compounds 15 (0.78mmol/kg) and 20 (0.39mmol/kg) showed remarkable 100% protection against PTZ induced convulsions with two and four fold increase in activity than sodium valproate (1.38mmol/kg), respectively. Molecular modeling studies showed hydrogen bonding interaction between 15 and Thr56 residues at the binding site of GABAA. Superposition, flexible alignment and surface mapping of 15, 20 and diazepam supports their biological resemblance where ADMET study suggested that those compounds could be used as oral anticonvulsants.

Synthesis, biological evaluation and molecular modeling study of 2-(1,3,4-thiadiazolyl-thio and 4-methyl-thiazolyl-thio)-quinazolin-4-ones as a new class of DHFR inhibitors.

A new series of 2-(1,3,4-thiadiazolyl- or 4-methyl-thiazolyl)thio-6-substituted-quinazolin-4-one analogs was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 29, 34, and 39 proved to be the most active DHFR inhibitors with IC50 values range of 0.1-0.6 µM. Compounds 28, 31 and 33 showed remarkable broad-spectrum antimicrobial activity comparable to the known antibiotic Gentamicin. Compounds 26, 33, 39, 43, 44, 50, 55 and 63 showed broad spectrum antitumor activity with GI values range of 10.1-100%. Molecular modeling study concluded that recognition with key amino acid Glu30, Phe31 and Phe34 is essential for binding. ADMET properties prediction of the active compounds suggested that compounds 29 and 34 could be orally absorbed with diminished toxicity.

Nonclassical antifolates, part 5. Benzodiazepine analogs as a new class of DHFR inhibitors: synthesis, antitumor testing and molecular modeling study.

A new series of tetrahydro-quinazoline and tetrahydro-1H-dibenzo[b,e][1,4]diazepine analogs were synthesized and tested for their DHFR inhibition and in vitro antitumor activity. Compound 35 showed a remarkable DHFR inhibitory potency (IC50, 0.004 µM) which is twenty fold more active than methotrexate (MTX). Compounds 17 and 23 proved to be fifteen fold more active than the known antitumor 5-FU, with MG-MID GI50, TGI, and LC50 values of 1.5, 46.8, 93.3 and 1.4, 17.4, 93.3 µM, respectively. Computer modeling studies allowed the identification that methoxy and methyl substituents, the π-system of the chalcone core, the nitrogen atoms, on the dibenzodiazepine ring as pharmacophoric features essential for activity. These mark points could be used as template model for further future optimization.

Nonclassical antifolates, part 4. 5-(2-aminothiazol-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiols as a new class of DHFR inhibitors: synthesis, biological evaluation and molecular modeling study.

A new series of compounds possessing 5-(2-aminothiazol-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiol skeleton was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, antitumor and schistosomicidal activities. Four active compounds were allocated, the antibacterial 22 (comparable to gentamicin and ciprofloxacin), the schistosomicidal 29 (comparable to praziquantel), the DHFR inhibitor 34 (IC50 0.03 µM, 2.7 fold more active than MTX), and the antitumor 36 (comparable to doxorubicin). Molecular modeling studies concluded that recognition with key amino acid Leu4 and Val1 is essential for DHFR binding. Flexible alignment and surface mapping revealed that the obtained model could be useful for the development of new class of DHFR inhibitors.

Synthesis, dihydrofolate reductase inhibition, antitumor testing, and molecular modeling study of some new 4(3H)-quinazolinone analogs.

In order to produce potent new leads for anticancer drugs, a new series of quinazoline analogs was designed to resemble methotrexate (MTX, 1) structure features and fitted with functional groups believed to enhance inhibition of mammalian DHFR activity. Molecular modeling studies were used to assess the fit of these compounds within the active site of human DHFR. The synthesized compounds were evaluated for their ability to inhibit mammalian DHFR in vitro and for their antitumor activity in a standard in vitro tissue culture assay panel. Compounds 28, 30, and 31 were the most active DHFR inhibitors with IC(50) values of 0.5, 0.4, and 0.4microM, respectively. The most active antitumor agents in this study were compounds 19, 31, 41, and 47 with median growth inhibitory concentrations (GI(50)) of 20.1, 23.5, 26.7, and 9.1microM, respectively. Of this series of compounds, only compound 31 combined antitumor potency with potent DHFR inhibition; the other active antitumor compounds (19, 41, and 47) all had DHFR IC(50) values above 15microM, suggesting that they might exert their antitumor potency through some other mode of action. Alternatively, the compounds could differ significantly in uptake or concentration within mammalian cells.