In vitro anti-Helicobacter pylori activity of BAS-118, a new benzamide derivative

Alanine racemase a promising Helicobacter pylori drug target inhibited by propanoic acid

Eradication of Helicobacter pylori, the class 1 carcinogen, faces several obstacles, which demand alternative options to conventional drug development methods. Alanine racemase (Alr) was proposed as H. pylori drug target, inhibited by propanoic acid (PA), in a previous in silico study. We investigated the possible treatment of H. pylori infection through Alr inhibition. A new model of H. pylori Alr was built, validated, and the binding of PA to the active site was modelled via molecular docking with a good docking score. PA minimum inhibitory concentration (MIC) against H. pylori ATCC 43504 and six H. pylori clinical isolates ranged from 312.5 to 416.7 ± 180 μg/ml and remained unchanged after 14 serial passages in increasing PA concentrations. The minimum bactericidal concentration of PA was 625 μg/ml. Selective Alr inhibition was confirmed by a significant PA MIC increase with increasing d-alanine concentrations. Similar PA MIC in other tested pathogens was recorded (312.5-625 μg/ml). PA lacked cytotoxicity in tested cell lines and efficiently eradicated H. pylori in a rat infection model. In conclusion, Alr is a promising broad-spectrum drug target, inhibited by PA without resistance development by repeated exposure for 14 serial passages.

Aspartate α-decarboxylase a new therapeutic target in the fight against Helicobacter pylori infection

Effective eradication therapy for Helicobacter pylori is a worldwide demand. Aspartate α-decarboxylase (ADC) was reported as a drug target in H. pylori, in an in silico study, with malonic acid (MA) as its inhibitor. We evaluated eradicating H. pylori infection through ADC inhibition and the possibility of resistance development. MA binding to ADC was modeled via molecular docking. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MA were determined against H. pylori ATCC 43504, and a clinical H. pylori isolate. To confirm selective ADC inhibition, we redetermined the MIC in the presence of products of the inhibited enzymatic pathway: β-alanine and pantothenate. HPLC was used to assay the enzymatic activity of H. pylori 6x-his tagged ADC in the presence of different MA concentrations. H. pylori strains were serially exposed to MA for 14 passages, and the MICs were determined. Cytotoxicity in different cell lines was tested. The efficiency of ADC inhibition in treating H. pylori infections was evaluated using a Sprague–Dawley (SD) rat infection model. MA spectrum of activity was determined in different pathogens. MA binds to H. pylori ADC active site with a good docking score. The MIC of MA against H. pylori ranged from 0.5 to 0.75 mg/mL with MBC of 1.5 mg/mL. Increasing β-alanine and pantothenate concentrations proportionally increased MA MIC. The 6x-his tagged ADC activity decreased by increasing MA concentration. No resistance to ADC inhibition was recorded after 14 passages; MA lacked cytotoxicity in all tested cell lines. ADC inhibition effectively eradicated H. pylori infection in SD rats. MA had MIC between 0.625 to 1.25 mg/mL against the tested bacterial pathogens. In conclusion, ADC is a promising target for effectively eradicating H. pylori infection that is not affected by resistance development, besides being of broad-spectrum presence in different pathogens. MA provides a lead molecule for the development of an anti-helicobacter ADC inhibitor. This provides hope for saving the lives of those at high risk of infection with the carcinogenic H. pylori.

Synthesis and molecular docking studies of some novel antimicrobial benzamides

Common use of classical antibiotics has caused to the growing emergence of many resistant strains of pathogenic bacteria. Therefore, we aimed to synthesize a number of N-(2-hydroxy-(4 or 5)-nitrophenyl)benzamide derivatives as a new class of antimicrobial compounds. Moreover, our second goal is to predict the interaction between active structures and enzymes (DNA -gyrase and FtsA) in the binding mode. In this study, thirteen N-(2-hydroxy-(4 or 5-nitrophenyl)-substituted-benzamides were synthesized and determined for their antimicrobial activity using the microdilution method. According to this work, none of the compounds showed any activity against Candida albicans and its clinical isolate. Some of the benzamides (4N1, 5N1, 5N2) displayed very significant activity against Staphylococcus aureus and MSSA with <4 µg/ml MIC value, even they were found to be more potent than ceftazidime. 4N1 was also found to be more effective than gentamicin against Enterococcus faecalis clinical isolate. Molecular docking studies revealed that 4N1, 5N1, and 5N2 showed a good interactions with DNA-gyrase. Moreover, 5N1 has interacted with FtsA enzyme in the binding mode, as well. Only compound 5N4 displayed very good activity against Escherichia coli ATCC 25922. These findings showed us that 4N1, 5N1, 5N2, and 5N4 could be lead compounds to discover new antibacterial candidates against multidrug-resistant strains.

Nickel-catalyzed aminocarbonylation of aryl halides using carbamoylsilane as an amide source

The nickel-catalyzed aminocarbonylation reaction of aryl halides using carbamoylsilanes as an amide source in toluene is developed leading to the formation of some tertiary or secondary aryl amides in good yields.

Palladium-catalyzed oxidative carbamoylation of isoquinoline N-oxides with formylamides by means of dual C–H oxidative coupling

A new palladium-catalyzed oxidative carbamoylation reaction of isoquinoline N-oxides with formylamides for the synthesis of isoquinoline-1-carboxamides is described.

Synthesis of Symmetrical Bisamides by Reaction between Aromatic Aldehydes and Alkyl Nitriles in the Presence of Chlorosulfonic Acid

Reaction between aromatic aldehydes and alkyl nitriles in the presence of chlorosulfonic acid leads to N-[alkanoylamino-(aryl)-methyl]- amide derivatives in excellent yields.

QSAR and pharmacophore analysis on amides against drug-resistant S. aureus

Considering the worth of developing new antibacterial agents against drug-resistant Stapylococcus aureus, the present study explores the structure-activity relationships analysis of N-(2-hydroxy-4(or 5)-nitro/aminophenyl)benzamide and phenylacetamide derivatives using classical QSAR and 3D-common-feature pharmacophore hypothese approaches. QSAR analysis revealed that the compounds possessing a methylene group between the phenyl and the carboxyamido moiety played a role for decreasing the activity. On the other side, substituent effects on position R1 was found important for the activity and holding a substituent possessing a minimum width property on this position like as alkyl groups enhanced the activity. Moreover, substituting position R3 with a group enhancing the electron-donor capability of the phenolic ring system increased the potency. 3D-common-feature pharmacophore approach considered that the conformational properties of the compounds were important for the activity against drug-resistant S. aureus and compounds possessing a benzamide moiety rather than phenylacetamide structure increased the activity. Furthermore, holding NO2 and OH groups on the phenyl ring attached to the benzamide moiety was important for improving the potency against drug-resistant S. aureus.

A novel class of selective anti-Helicobacter pylori agents 2-oxo-2H-chromene-3-carboxamide derivatives

A novel class of selective anti-Helicobacter pylori agents, 2-oxo-2H-chromene-3-carboxamide derivatives, were prepared and evaluated for their anti-bacterial activity. All synthesized compounds showed little or no activity against different species of Gram-positive and Gram-negative bacteria and against various strains of pathogenic fungi. Some of them exhibited a potent and specific inhibitory effect on the growth of H. pylori, including metronidazole-resistant strains, in the 0.0039-16 microg/mL MIC range. A cytotoxic screening by the Trypan blue dye exclusion assay was also carried out on the most active compounds as anti-H. pylori agents. Among the derivatives examined for their cytotoxic potential, a number of them induced low cytotoxic effects.

Synthesis and biological evaluation of new N-(2-hydroxy-4(or 5)-nitro/aminophenyl)benzamides and phenylacetamides as antimicrobial agents

A new series of N-(2-hydroxy-4(or 5)-nitro/aminophenyl)benzamide and phenylacetamide derivatives (1a-1n, 2a-2n) were synthesized and evaluated for antibacterial and antifungal activities against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and their drug-resistant isolate. Microbiological results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between 500 and 1.95 microg/ml. Benzamide derivative 1d exhibited the greatest activity with MIC values of 1.95, 3.9, and 7.8 microg/ml against drug-resistant B. subtilis, B. subtilis, and S. aureus, respectively.