Antibacterial Potential of Symmetrical Twin-Drug 3,6-Diaminoxanthones.

Global health faces a significant issue with the rise of infectious diseases caused by bacteria, fungi, viruses, and parasites. The increasing number of multi-drug resistant microbial pathogens severely threatens public health worldwide. Antibiotic-resistant pathogenic bacteria, in particular, present a significant challenge.

Insights into the antimicrobial properties of a cationic steroid and antibiofilm performance in PDMS-based coatings to potentially treat urinary infections.

Currently, multidrug-resistant (MDR) infections are one of the most important threats, driving the search for new antimicrobial compounds. Cationic peptide antibiotics (CPAs) and ceragenins (CSAs) contain in their structures cationic groups and adopt a facially amphiphilic conformation, conferring the ability to permeate the membranes of bacteria and fungi. Keeping these features in mind, an amine steroid, DOCA-NH2, was found to be active against reference strains and MDR isolates of Gram-positive and and Gram-negative and .

Antitumor Effect of Chalcone Derivatives against Human Prostate (LNCaP and PC-3), Cervix HPV-Positive (HeLa) and Lymphocyte (Jurkat) Cell Lines and Their Effect on Macrophage Functions.

Chalcones are synthetic and naturally occurring compounds that have been widely investigated as anticancer agents. In this work, the effect of chalcones - against the metabolic viability of cervical (HeLa) and prostate (PC-3 and LNCaP) tumor cell lines was tested, to compare the activity against solid and liquid tumor cells. Their effect was also evaluated on the Jurkat cell line.

Derivatives of Trimethoxybenzoic Acid and Gallic Acid as Potential Efflux Pump Inhibitors: In Silico and In Vitro Studies.

The overexpression of efflux pumps is one of the strategies used by bacteria to resist antibiotics and could be targeted to circumvent the antibiotic crisis. In this work, a series of trimethoxybenzoic acid derivatives previously described as antifouling compounds was explored for potential antimicrobial activity and efflux pump (EP) inhibition. First, docking studies on the acridine resistance proteins A and B coupled to the outer membrane channel TolC (AcrAB-TolC) efflux system and a homology model of the quinolone resistance protein NorA EP were performed on 11 potential bioactive trimethoxybenzoic acid and gallic acid derivatives.

Antifungal Activity of a Library of Aminothioxanthones.

Fungal infections are one of the main causes of mortality and morbidity worldwide and taking into account the increasing incidence of strains resistant to classical antifungal drugs, the development of new agents has become an urgent clinical need. Considering that thioxanthones are bioisosteres of xanthones with known anti-infective actions, their scaffolds were selected for this study. A small library of synthesized aminothioxanthones (-) was evaluated for in vitro antifungal activity against , , and ; for the active compounds, the spectrum was further extended to other clinically relevant pathogenic fungi.

High diversity of pathogenic Escherichia coli clones carrying mcr-1 among gulls underlines the need for strategies at the environment-livestock-human interface.

The expansion of mcr-carrying bacteria is a well-recognized public health problem. Measures to contain mcr spread have mainly been focused on the food-animal production sector. Nevertheless, the spread of MCR producers at the environmental interface particularly driven by the increasing population of gulls in coastal cities has been less explored.

BDDE-Inspired Chalcone Derivatives to Fight Bacterial and Fungal Infections.

The growing number of infectious diseases around the world threatens the effective response of antibiotics, contributing to the increase in antibiotic resistance seen as a global health problem. Currently, one of the main challenges in antimicrobial drug discovery is the search for new compounds that not only exhibit antimicrobial activity, but can also potentiate the antimicrobial activity and revert antibiotics' resistance, through the interference with several mechanisms, including the inhibition of efflux pumps (EPs) and biofilm formation. Inspired by macroalgae brominated bromophenol BDDE with antimicrobial activity, a series of 18 chalcone derivatives, including seven chalcones (-), six dihydrochalcones (-, and -) and five diarylpropanes (-, and and ), was prepared and evaluated for its antimicrobial activity and potential to fight antibiotic resistance.

New diarylpentanoids and chalcones as potential antimicrobial adjuvants.

Antimicrobial resistance arises due to several adaptation mechanisms, being the overexpression of efflux pumps (EPs) one of the most worrisome. In bacteria, EPs can also play important roles in virulence, quorum-sensing (QS) and biofilm formation. To identify new potential antimicrobial adjuvants, a library of diarylpentanoids and chalcones was synthesized and tested.

Enantioselectivity of Chiral Derivatives of Xanthones in Virulence Effects of Resistant Bacteria.

Antimicrobial peptides are one of the lines of defense produced by several hosts in response to bacterial infections. Inspired by them and recent discoveries of xanthones as bacterial efflux pump inhibitors, chiral amides with a xanthone scaffold were planned to be potential antimicrobial adjuvants. The chiral derivatives of xanthones were obtained by peptide coupling reactions between suitable xanthones with enantiomerically pure building blocks, yielding derivatives with high enantiomeric purity.

Effect of 1-Carbaldehyde-3,4-dimethoxyxanthone on Prostate and HPV-18 Positive Cervical Cancer Cell Lines and on Human THP-1 Macrophages.

Xanthone derivatives have shown promising antitumor properties, and 1-carbaldehyde-3,4-dimethoxyxanthone () has recently emerged as a potent tumor cell growth inhibitor. In this study, its effect was evaluated (MTT viability assay) against a new panel of cancer cells, namely cervical cancer (HeLa), androgen-sensitive (LNCaP) and androgen-independent (PC-3) prostate cancer, and nonsolid tumor derived cancer (Jurkat) cell lines. The effect of xanthone on macrophage functions was also evaluated.

Antimicrobial Activity of a Library of Thioxanthones and Their Potential as Efflux Pump Inhibitors.

The overexpression of efflux pumps is one of the causes of multidrug resistance, which leads to the inefficacy of drugs. This plays a pivotal role in antimicrobial resistance, and the most notable pumps are the AcrAB-TolC system (AcrB belongs to the resistance-nodulation-division family) and the NorA, from the major facilitator superfamily. In bacteria, these structures can also favor virulence and adaptation mechanisms, such as quorum-sensing and the formation of biofilm.

Prenylated phenylbutyrolactones from cultures of a marine sponge-associated fungus Aspergillus flavipes KUFA1152.

Four undescribed prenylated phenylbutyrolactones, aspulvinones R, S, T and U, were isolated together with the previously reported aspulvinones A, B', H and 4-hydroxy-3,5-bis(3-methylbut-2-en-1-yl)benzaldehyde, from cultures of the marine sponge-derived fungus Aspergillus flavipes KUFA1152. The structures of the undescribed compounds were established on the basis of extensive analysis of 1D and 2D NMR and HRMS spectra. In the case of aspulvinone T, the absolute configuration of its stereogenic carbon was established by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra.

1,3-Dioxepine and spiropyran derivatives of viomellein and other dimeric naphthopyranones from cultures of Aspergillus elegans KUFA0015 and their antibacterial activity.

Two undescribed viomellein derivatives, xanthoelegansin and spiroxanthoelegansin, were isolated together with clavatol, sitosteanone, vioxanthin, xanthomegnin, viomellein, rubrosulphin, rubrosulphin diacetate, viopurpurin , ochratoxin A, ochratoxin A methyl ester, ochratoxin B and ochratoxin β, from cultures of the marine sponge-associated fungus Aspergillus elegans KUFA0015. The structures of the undescribed compounds were established based on an extensive analysis of 1D and 2D NMR spectra as well as HRMS data. The structure of xanthoelegansin and the absolute configuration of its stereogenic carbons were confirmed by X-ray analysis.

New marine-derived indolymethyl pyrazinoquinazoline alkaloids with promising antimicrobial profiles.

Due to the emergence of multidrug-resistant pathogenic microorganisms, the search for novel antimicrobials is urgent. Inspired by marine alkaloids, a series of indolomethyl pyrazino [1,2-]quinazoline-3,6-diones was prepared using a one-pot microwave-assisted multicomponent polycondensation of amino acids. The compounds were evaluated for their antimicrobial activity against a panel of nine bacterial strains and five fungal strains.

Synthesis of a Small Library of Nature-Inspired Xanthones and Study of Their Antimicrobial Activity.

A series of thirteen xanthones - was prepared based on substitutional (appendage) diversity reactions. The series was structurally characterized based on their spectral data and HRMS, and the structures of xanthone derivatives , , and were determined by single-crystal X-ray diffraction. This series, along with an in-house series of aminated xanthones - was tested for in-vitro antimicrobial activity against seven bacterial (including two multidrug-resistant) strains and five fungal strains.

Erubescensoic Acid, a New Polyketide and a Xanthonopyrone SPF-3059-26 from the Culture of the Marine Sponge-Associated Fungus KUFA 0220 and Antibacterial Activity Evaluation of Some of Its Constituents.

A new polyketide erubescensoic acid (), and the previously reported xanthonopyrone, SPF-3059-26 (), were isolated from the uninvestigated fractions of the ethyl acetate crude extract of the marine sponge-associated fungus KUFA0220. The structures of the new compound, erubescensoic acid (), and the previously reported SPF-3059-26 (), were elucidated by extensive analysis of 1D and 2D-NMR spectra as well as HRMS. The absolute configuration of the stereogenic carbon of erubescensoic acid () was determined by X-ray analysis.

Occurrence of mcr-1 in Escherichia coli from rabbits of intensive farming.

The emergence of mobile colistin resistance genes (mcr) is yet another challenge in the fight against antimicrobial resistance, with reports proving the dissemination of these genes in different countries and different environments being of great concern. In the present study, we describe the recovery of three E. coli strains with mcr-1 gene in IncHI2 plasmids from intestinal content of necropsied meat rabbits reared in two intensive production systems in Portugal.

Chromone Derivatives and Other Constituents from Cultures of the Marine Sponge-Associated Fungus KUFA0220 and Their Antibacterial Activity.

A previously unreported chromene derivative, 1-hydroxy-12-methoxycitromycin (), and four previously undescribed chromone derivatives, including pyanochromone (), spirofuranochromone (), 7-hydroxy-6-methoxy-4-oxo-3-[(1)-3-oxobut-1-en-1-yl]-4-chromene-5-carboxylic acid (), a pyranochromone dimer () were isolated, together with thirteen known compounds: β-sitostenone, ergosterol 5,8-endoperoxide, citromycin (), 12-methoxycitromycin (), myxotrichin D (), 12-methoxycitromycetin (), anhydrofulvic acid (), myxotrichin C (), penialidin D (), penialidin F (), SPF-3059-30 (), GKK1032B () and secalonic acid A (), from cultures of the marine sponge- associated fungus KUFA0220. Compounds ⁻, , , , ⁻, were tested for their antibacterial activity against Gram-positive and Gram-negative reference and multidrug-resistant strains isolated from the environment. Only exhibited an in vitro growth inhibition of all Gram-positive bacteria whereas showed growth inhibition of methicillin-resistant (MRSA).