Recent trends and challenges to overcome Pseudomonas aeruginosa infections.

INTRODUCTION: Pseudomonas aeruginosa (PA) is a Gram-negative bacterium that can cause a wide range of severe infections in immunocompromised patients. The most difficult challenge is due to its ability to rapidly develop multi drug-resistance. New strategies are urgently required to improve the outcome of patients with PA infections. The present patent review highlights the new molecules acting on different targets involved in the antibiotic resistance. AREA COVERED: This review offers an insight into new potential PA treatment disclosed in patent literature. From a broad search of documents claiming new PA inhibitors, we selected and summarized molecules that showed in vitro and in vivo activity against PA spp. in the period 2020 and 2023. We collected the search results basing on the targets explored. EXPERT OPINION: This review examined the main patented compounds published in the last three years, with regard to the structural novelty and the identification of innovative targets. The main areas of antibiotic resistance have been explored. The compounds are structurally unrelated to earlier antibiotics, characterized by a medium-high molecular weight and the presence of heterocycle rings. Peptides and antibodies have also been reported as potential alternatives to chemical treatment, hereby expanding the therapeutic possibilities in this field.

Peroxisome Proliferator-Activated Receptor agonists and antagonists: an updated patent review (2020-2023).

INTRODUCTION: The search for novel compounds targeting Peroxisome Proliferator-Activated Receptors (PPARs) is currently ongoing, starting from the previous successfully identification of selective, dual or pan agonists. In last years, researchers' efforts are mainly paid to the discovery of PPARγ and δ modulators, both agonists and antagonists, selective or with a dual-multitarget profile. Some of these compounds are currently under clinical trials for the treatment of primary biliary cirrhosis, nonalcoholic fatty liver disease, hepatic, and renal diseases. AREAS COVERED: A critical analysis of patents deposited in the range 2020-2023 was carried out. The novel compounds discovered were classified as selective PPAR modulators, dual and multitarget PPAR agonists. The use of PPAR ligands in combination with other drugs was also discussed, together with novel therapeutic indications proposed for them. EXPERT OPINION: From the analysis of the patent literature, the current emerging landscape sees the necessity to obtain PPAR multitarget compounds, with a balanced potency on three subtypes and the ability to modulate different targets. This multitarget action holds great promise as a novel approach to complex disorders, as metabolic, inflammatory diseases, and cancer. The utility of PPAR ligands in the immunotherapy field also opens an innovative scenario, that could deserve further applications.

Recent developments of agents targeting Vibrio cholerae: patents and literature data.

INTRODUCTION: Vibrio cholerae bacteria cause an infection characterized by acute diarrheal illness in the intestine. Cholera is sustained by people swallowing contaminated food or water. Even though symptoms can be mild, if untreated disease becomes severe and life-threatening, especially in low-income countries. AREAS COVERED: After a description of the most recent literature on the pathophysiology of this infection, we searched for patents and literature articles following the PRISMA guidelines, filtering the results disclosed from 2020 to present. Moreover, some innovative molecular targets (e.g., carbonic anhydrases) and pathways to counteract this rising problem were also discussed in terms of design, structure-activity relationships and structural analyses. EXPERT OPINION: This review aims to cover and analyze the most recent advances on the new druggable targets and bioactive compounds against this fastidious pathogen, overcoming the use of old antibiotics which currently suffer from high resistance rate.

Novel therapeutic opportunities for Toxoplasma gondii, Trichomonas vaginalis, and Giardia intestinalis infections.

INTRODUCTION: Toxoplasma gondii, Trichomonas vaginalis, and Giardia intestinalis are the causative agents of toxoplasmosis, trichomoniasis, and giardiasis, three important infections threatening human health and affecting millions of people worldwide. Although drugs and treatment are available to fight these protozoan parasites, side effects and increasing drug resistance require continuous efforts for the development of novel effective drugs. AREAS COVERED: The patents search was carried out in September/October 2022 with four official scientific databases (Espacenet, Scifinder, Reaxys, Google Patents). Treatments for toxoplasmosis, trichomoniasis, and giardiasis (2015-2022) have been grouped according to their chemotypes. In particular, novel chemical entities have been reported and investigated for their structure-activity relationship, when accessible. On the other hand, drug repurposing, extensively exploited to obtain novel antiprotozoal treatment, has been in-depth described. Finally, natural metabolites and extracts have also been reported. EXPERT OPINION: T. gondii, T. vaginalis, and G. intestinalis are protozoan infections usually controlled by immune system in immunocompetent patients; however, they could represent a threatening health for immunocompromised people. The needs of novel effective drugs, endowed with new mechanisms of actions, arises from the increasing drug resistance affecting antibiotic as well as antiprotozoal therapies. In this review different therapeutic approaches to treat protozoan infections have been reported.

A Novel Class of Dual-Acting DCH-CORMs Counteracts Oxidative Stress-Induced Inflammation in Human Primary Tenocytes.

Carbon monoxide (CO) can prevent cell and tissue damage by restoring redox homeostasis and counteracting inflammation. CO-releasing molecules (CORMs) can release a controlled amount of CO to cells and are emerging as a safer therapeutic alternative to delivery of CO in vivo. Sustained oxidative stress and inflammation can cause chronic pain and disability in tendon-related diseases, whose therapeutic management is still a challenge. In this light, we developed three small subsets of 1,5-diarylpyrrole and pyrazole dicobalt(0)hexacarbonyl (DCH)-CORMs to assess their potential use in musculoskeletal diseases. A myoglobin-based spectrophotometric assay showed that these CORMs act as slow and efficient CO-releasers. Five selected compounds were then tested on human primary-derived tenocytes before and after hydrogen peroxide stimulation to assess their efficacy in restoring cell redox homeostasis and counteracting inflammation in terms of PGE2 secretion. The obtained results showed an improvement in tendon homeostasis and a cytoprotective effect, reflecting their activity as CO-releasers, and a reduction of PGE2 secretion. As these compounds contain structural fragments of COX-2 selective inhibitors, we hypothesized that such a composite mechanism of action results from the combination of CO-release and COX-2 inhibition and that these compounds might have a potential role as dual-acting therapeutic agents in tendon-derived diseases.

Synthesis and Evaluation of Thymol-Based Synthetic Derivatives as Dual-Action Inhibitors against Different Strains of H. pylori and AGS Cell Line.

Following a similar approach on carvacrol-based derivatives, we investigated the synthesis and the microbiological screening against eight strains of H. pylori, and the cytotoxic activity against human gastric adenocarcinoma (AGS) cells of a new series of ether compounds based on the structure of thymol. Structural analysis comprehended elemental analysis and 1H/13C/19F NMR spectra. The analysis of structure-activity relationships within this molecular library of 38 structurally-related compounds reported that some chemical modifications of the OH group of thymol led to broad-spectrum growth inhibition on all isolates. Preferred substitutions were benzyl groups compared to alkyl chains, and the specific presence of functional groups at para position of the benzyl moiety such as 4-CN and 4-Ph endowed the most anti-H. pylori activity toward all the strains with minimum inhibitory concentration (MIC) values up to 4 µg/mL. Poly-substitution on the benzyl ring was not essential. Moreover, several compounds characterized by the lowest minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values against H. pylori were also tested in order to verify a cytotoxic effect against AGS cells with respect to 5-fluorouracil and carvacrol. Three derivatives can be considered as new lead compounds alternative to current therapy to manage H. pylori infection, preventing the occurrence of severe gastric diseases. The present work confirms the possibility to use natural compounds as templates for the medicinal semi-synthesis.

Antimicrobial activity, synergism and inhibition of germ tube formation by Crocus sativus-derived compounds against Candida spp.

The limited arsenal of synthetic antifungal agents and the emergence of resistant Candida strains have prompted the researchers towards the investigation of naturally occurring compounds or their semisynthetic derivatives in order to propose new innovative hit compounds or new antifungal combinations endowed with reduced toxicity. We explored the anti-Candida effects, for the first time, of two bioactive compounds from Crocus sativus stigmas, namely crocin 1 and safranal, and some semisynthetic derivatives of safranal obtaining promising biological results in terms of minimum inhibitory concentration/minimum fungicidal concentration (MIC/MFC) values, synergism and reduction in the germ tube formation. Safranal and its thiosemicarbazone derivative 5 were shown to display good activity against Candida spp.

Bioactive compounds of Crocus sativus L. and their semi-synthetic derivatives as promising anti-Helicobacter pylori, anti-malarial and anti-leishmanial agents.

Crocus sativus L. is known in herbal medicine for the various pharmacological effects of its components, but no data are found in literature about its biological properties toward Helicobacter pylori, Plasmodium spp. and Leishmania spp. In this work, the potential anti-bacterial and anti-parasitic effects of crocin and safranal, two important bioactive components in C. sativus, were explored, and also some semi-synthetic derivatives of safranal were tested in order to establish which modifications in the chemical structure could improve the biological activity. According to our promising results, we virtually screened our compounds by means of molecular modeling studies against the main H. pylori enzymes in order to unravel their putative mechanism of action.

(Thiazol-2-yl)hydrazone derivatives from acetylpyridines as dual inhibitors of MAO and AChE: synthesis, biological evaluation and molecular modeling studies.

Several (thiazol-2-yl)hydrazone derivatives from 2-, 3- and 4-acetylpyridine were synthesized and tested against human monoamine oxidase (hMAO) A and B enzymes. Most of them had an inhibitory effect in the low micromolar/high nanomolar range, being derivatives of 4-acetylpyridine selective hMAO-B inhibitors also at low nanomolar concentrations. The structure-activity relationship, as confirmed by molecular modeling studies, proved that the pyridine ring linked to the hydrazonic nitrogen and the substituted aryl moiety at C4 of the thiazole conferred the inhibitory effects on hMAO enzymes. Successively, the strongest hMAO-B inhibitors were tested toward acetylcholinesterase (AChE) and the most interesting compound showed activity in the low micromolar range. Our results suggest that this scaffold could be further investigated for its potential multi-targeted role in the discovery of new drugs against the neurodegenerative diseases.

Modern extraction techniques and their impact on the pharmacological profile of Serenoa repens extracts for the treatment of lower urinary tract symptoms.

BACKGROUND: Bioactive compounds from plants (i.e., Serenoa repens) are often used in medicine in the treatment of several pathologies, among which benign prostatic hyperplasia (BPH) associated to lower urinary tract symptoms (LUTS). DISCUSSION: There are different techniques of extraction, also used in combination, with the aim of enhancing the amount of the target molecules, gaining time and reducing waste of solvents. However, the qualitative and quantitative composition of the bioactives depends on the extractive process, and so the brands of the recovered products from the same plant are different in terms of clinical efficacy (no product interchangeability among different commercial brands). SUMMARY: In this review, we report on several and recent extraction techniques and their impact on the composition/biological activity of S. repens-based available products.

Synthesis and biological evaluation of novel 2,4-disubstituted-1,3-thiazoles as anti-Candida spp. agents.

A new series of [4-(4'-substituted-phenyl)thiazol-2-yl]hydrazine derivatives were synthesized in good yield (86-99%) and characterized by elemental analysis, IR, (1)H NMR, and mass spectral studies. The compounds were assayed for their in vitro broad-spectrum antifungal activity, compared to clotrimazole and fluconazole, against 20 clinical isolates of pathogenic Candida spp., representing five different species. The results showed that the presence of heterocyclic or bicyclic rings on hydrazone moiety in position C2 of thiazole revealed a promising selective inhibitory activity especially against Candida albicans and Candida glabrata.

Synthesis, stereochemical separation, and biological evaluation of selective inhibitors of human MAO-B: 1-(4-arylthiazol-2-yl)-2-(3-methylcyclohexylidene)hydrazines.

Novel 1-(4-arylthiazol-2-yl)-2-(3-methylcyclohexylidene)hydrazine derivatives have been investigated for their ability to inhibit selectively the activity of the human B isoform of monoamine oxidase. These compounds were obtained as racemates and (R)-enantiomers by a stereoconservative synthetic pattern in high yield and enantiomeric excess. The (S)-enantiomers of the most active derivatives have been separated by enantioselective HPLC. All compounds showed selective activity against hMAO-B with IC(50) ranging between 21.90 and 0.018 microM.

Synthesis, selective anti-Helicobacter pylori activity, and cytotoxicity of novel N-substituted-2-oxo-2H-1-benzopyran-3-carboxamides.

N-substituted-3-carboxamido-coumarin derivatives were prepared and evaluated for selective antibacterial activity against 20 isolates of Helicobacter pylori clinical strains, including five metronidazole resistant ones. Some of them possessed the best activity against H. pylori metronidazole resistant strains with MIC values lower than the drug reference (metronidazole). Furthermore, anti-inflammatory activity through the inhibition of the IL-8 production was investigated.

Investigations on the 2-thiazolylhydrazyne scaffold: synthesis and molecular modeling of selective human monoamine oxidase inhibitors.

A new series of [4-(3-methoxyphenyl)-thiazol-2-yl]hydrazyne derivatives were synthesized in good yield (71-99%) and characterized by elemental analysis and (1)H NMR studies. The compounds were assayed for their in vitro human monoamine oxidase (hMAO) inhibitory activity and selectivity and most of them showed IC(50) values in the nanomolar range, thus demonstrating our interest in this privileged scaffold. The most active and selective derivative (20), bearing a pyridine moiety on the CN, displayed IC(50)=3.81+/-0.12 nM and selectivity ratio=119 toward hMAO-B. Molecular modeling studies were carried out on recent and high resolution hMAO-A and hMAO-B crystallographic structures to better justify the enzyme-inhibitor interaction toward hMAO isoforms and to explain the structure-activity relationship of this kind of inhibitors.

Synthesis, semipreparative HPLC separation, biological evaluation, and 3D-QSAR of hydrazothiazole derivatives as human monoamine oxidase B inhibitors.

The present study reports on synthesis in high yields (70-99%), HPLC enantioseparation, inhibitory activity against human monoamino oxidases, and molecular modeling including 3D-QSAR studies, of a large series of (4-aryl-thiazol-2-yl)hydrazones (1-45). Most of the synthesized compounds proved to be potent and selective inhibitors of hMAO-B isoform in the micromolar or nanomolar range, thus demonstrating that hydrazothiazole could be considered a good pharmacophore to design new hMAO-B inhibitors. Due to the presence in some derivatives of a chiral center, we also performed a semipreparative chromatographic enantioseparation of these compounds obtained by a stereoconservative pattern. The separated enantiomers were submitted to in vitro biological evaluation to point out the stereorecognition of the active site of the enzyme towards these structures. Finally, a 3D-QSAR study was carried out using Comparative Molecular Field Analysis (CoMFA), aiming to deduce rational guidelines for the further structural modification of these lead compounds.

Synthesis and inhibitory activity against human monoamine oxidase of N1-thiocarbamoyl-3,5-di(hetero)aryl-4,5-dihydro-(1H)-pyrazole derivatives.

A series of N1-thiocarbamoyl-3,5-di(hetero)aryl-4,5-dihydro-(1H)-pyrazole derivatives has been synthesized and assayed for their ability to inhibit the activity of the A and B isoforms of human monoamine oxidase (hMAO). Some of these compounds were endowed with a selective inhibitory activity against hMAO-B in the micromolar range. The most active of the series is the compound 13, N1-thiocarbamoyl-3-(fur-2'-yl)-5-(4'-fluoro-phenyl)-4,5-dihydro-(1H)-pyrazole, with IC(50) 2.75+/-0.81muM value and selectivity ratio of 25, which is the best candidate for further investigations.

Synthesis and evaluation of 4-acyl-2-thiazolylhydrazone derivatives for anti-Toxoplasma efficacy in vitro.

A new series of 4-acyl-2-thiazolylhydrazone derivatives was synthesized and screened for its in vitro activity against Toxoplasma gondii. We evaluated parasite growth inhibition and cytotoxicity, inhibition of replication, and inhibition of parasite invasion of host cells. The biological results indicated that some substances had an antiproliferative effect against intracellular T. gondii tachyzoites cultivated in vitro.

Synthesis, molecular modeling, and selective inhibitory activity against human monoamine oxidases of 3-carboxamido-7-substituted coumarins.

A large series of 3-carboxamido-7-substituted coumarins have been synthesized and tested in vitro for their human monoamine oxidase A and B (hMAO-A and hMAO-B) inhibitory activity. Taking into account all the relevant structural information on MAOs reported in the literature, we made some changes in the coumarin nucleus and examined with particular attention the effect on activity and selectivity of substituting at position 3 with N-aryl or N-alkyl carboxamide and at position 7 with a benzyloxy or a 4'-F-benzyloxy group. Some of the assayed compounds proved to be potent, selective inhibitors of hMAO-B with IC(50) values in the micromolar range. To better understand the enzyme-inhibitor interaction and to explain the selectivity of the most active compounds toward hMAOs, molecular modeling studies were carried out on new, high resolution, hMAO-A and hMAO-B crystallographic structures.

A novel histone acetyltransferase inhibitor modulating Gcn5 network: cyclopentylidene-[4-(4'-chlorophenyl)thiazol-2-yl)hydrazone.

Acetylation is a key modulator of genome accessibility through decondensation of the chromatin structure. The balance between acetylation and opposite deacetylation is, in fact, a prerequisite for several cell functions and differentiation. To find modulators of the histone acetyltransferase Gcn5p, we performed a phenotypic screening on a set of newly synthesized molecules derived from thiazole in budding yeast Saccharomyces cerevisiae. We selected compounds that induce growth inhibition in yeast strains deleted in genes encoding known histone acetyltransferases. A novel molecule CPTH2, cyclopentylidene-[4-(4'-chlorophenyl)thiazol-2-yl)hydrazone, was selected based on its inhibitory effect on the growth of a gcn5Delta strain. We demonstrated a specific chemical-genetic interaction between CPTH2 and HAT Gcn5p, indicating that CPTH2 inhibits the Gcn5p dependent functional network. CPTH2 inhibited an in vitro HAT reaction, which is reverted by increasing concentration of histone H3. In vivo, it decreased acetylation of bulk histone H3 at the specific H3-AcK14 site. On the whole, our results demonstrate that CPTH2 is a novel HAT inhibitor modulating Gcn5p network in vitro and in vivo.

Synthesis, stereochemical identification, and selective inhibitory activity against human monoamine oxidase-B of 2-methylcyclohexylidene-(4-arylthiazol-2-yl)hydrazones.

A series of 2-methylcyclohexylidene-(4-arylthiazol-2-yl)hydrazones have been investigated for their ability to inhibit selectively the activity of the human A and B isoforms of monoamine oxidase (MAO). The target compounds, which present a stereogenic center on the cyclohexane ring, were obtained as pure (R) and (S) enantiomers by enantioselective HPLC. The absolute configuration of homochiral forms isolated on a semipreparative scale was obtained by a combined strategy based on chemical correlation and single-crystal X-ray diffraction. All compounds showed higher activity against the human MAO-B isoform with IC50 values ranging between 26.81 +/- 2.74 microM and 14.20 +/- 0.26 nM, and the assays carried out on the pure enantiomers showed higher activity for the (R) form. A computational study was performed by molecular mechanics, DFT-based quantomechanics, and docking techniques on the most active and human MAO-B selective inhibitor 8.