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1.
Mar Drugs ; 22(6)2024 May 27.
Article in English | MEDLINE | ID: mdl-38921554

ABSTRACT

Five new naphthalene derivatives dalesconosides A-D, F (1-4, 6), a known synthetic analogue named dalesconoside E (5), and eighteen known compounds (7-24) were isolated from Daldinia eschscholzii MCZ-18, which is an endophytic fungus obtained from the Chinese mangrove plant Ceriops tagal. Differing from previously reported naphthalenes, compounds 1 and 2 were bearing a rare ribofuranoside substituted at C-1 and the 5-methyltetrahydrofuran-2,3-diol moiety, respectively. Their structures were determined by detailed nuclear magnetic resonance (NMR) and mass spectroscopic (MS) analyses, while the absolute configurations were established by theoretical electronic circular dichroism (ECD) calculation. Compounds 1, 3, 13-17 and 19 showed broad ranges of antimicrobial spectrum against five indicator test microorganisms (Enterococcus faecalis, Methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans); especially, 1, 16 and 17 were most potent. The variations in structure and attendant biological activities provided fresh insights concerning structure-activity relationships for the naphthalene derivatives.


Subject(s)
Microbial Sensitivity Tests , Naphthalenes , Naphthalenes/pharmacology , Naphthalenes/chemistry , Naphthalenes/isolation & purification , Structure-Activity Relationship , Magnetic Resonance Spectroscopy , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Candida albicans/drug effects , Molecular Structure , Rhizophoraceae/microbiology , Endophytes/chemistry , Anti-Infective Agents/pharmacology , Anti-Infective Agents/chemistry , Anti-Infective Agents/isolation & purification
2.
J Environ Manage ; 362: 121334, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38824890

ABSTRACT

A series of V-xCe/Ti catalysts was prepared by a step impregnation method with gradual increased Ce amount. Compared to the commercial V-W/Ti catalysts, the V-xCe/Ti catalysts exhibited considerably higher COx selectivity during the oxidation of naphthalene (Nap), and less intermediates or by-products were detected both in gas phase and on the surface of the catalysts. Through a series of characterizations, it was found that abundance of weak basic sites in the form of OH was introduced by Ce, as well as the oxygen vacancies caused by the redox cycle of V4++Ce4+↔V5++Ce3+. The weak basic sites introduced by Ce could greatly enhance the Nap adsorption, and the Nap adsorbed was quickly converted to naphthol on Ce-OH. Furthermore, V existed at a high valence with the interaction of V and Ce, and the oxygen vacancies also increased the Oads and OOH. It improved the redox ability and the regeneration of Ce-OH on V-xCe/Ti catalysts. The intermediates could be further oxidized, and the Ce-OH consumed in the reaction could recover quickly. Therefore, almost 100% Nap conversion and a high COx selectivity was observed in the V-xCe/Ti catalysts system.


Subject(s)
Naphthalenes , Oxidation-Reduction , Naphthalenes/chemistry , Catalysis , Adsorption
3.
Biosci Biotechnol Biochem ; 88(7): 719-726, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38758077

ABSTRACT

The Diels-Alder (DA) reaction, specifically referring to the [4 + 2] cycloaddition reaction in pericyclic reactions, is a process that forms two carbon-carbon covalent bonds in a single step via an electron ring transition state. Among the secondary metabolites produced by microorganisms, numerous compounds are biosynthesized through DA reactions, most of which are enzymatic. Our research group has discovered an enzyme named Diels-Alderase (DAase) that catalyzes the DA reaction in filamentous fungi, and we have been investigating its catalytic mechanism. This review describes the reported microbial DAase enzymes, with a particular focus on those involved in the construction of the decalin ring.


Subject(s)
Cycloaddition Reaction , Naphthalenes , Naphthalenes/chemistry , Naphthalenes/metabolism , Fungi/enzymology , Fungal Proteins/chemistry , Fungal Proteins/metabolism
4.
Chem Commun (Camb) ; 60(49): 6304-6307, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38818574

ABSTRACT

A commercially available naphthalene fluorophore serves as a ratiometric indicator for albumin, showcasing its applications in albumin-based supramolecular recognition.


Subject(s)
Fluorescent Dyes , Naphthalenes , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Naphthalenes/chemistry , Humans , Spectrometry, Fluorescence , Molecular Structure , Serum Albumin, Human/analysis , Serum Albumin, Human/chemistry
5.
Chemosphere ; 360: 142398, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38789053

ABSTRACT

Both thermal and environmental processes are significant factors influencing the existing characteristics, e.g., congener distributions, and existing levels, of polychlorinated naphthalenes (PCNs) in the environment. Soil plays an important role in the life cycle of PCNs, but degradation of PCNs in soils has never been reported. In this study, we collected surface soil samples from 13 cities in the Yangtze River Delta, which is one of the most crowded areas of China and analyzed the samples for 75 PCNs. The long-range transportation from polluted areas was the major source for PCNs in remote areas, but the PCN profiles in remote areas reported in our previous studies were different from those in human settlement in this study, indicating there is a transformation of PCNs after emissions from anthropogenic activities. Two experiments were then designed to reveal the degradation mechanisms, including influencing factors, products, and pathways, of PCNs in surface soils. Based on the experiments, we found that the major factor driving the losses of PCNs in surface soils was volatilization, followed by photo irradiation and microbial metabolism. Under photo-irradiation, the PCN structures would be destroyed through a process of dechlorination followed by oxidation. In addition, the dechlorination pathways of PCNs have been established and found to be significantly influenced by the structure-related parameters.


Subject(s)
Naphthalenes , Rivers , Soil Pollutants , Soil , China , Naphthalenes/chemistry , Naphthalenes/analysis , Soil Pollutants/analysis , Soil Pollutants/chemistry , Soil/chemistry , Rivers/chemistry , Environmental Monitoring , Hydrocarbons, Chlorinated/analysis , Hydrocarbons, Chlorinated/chemistry , Biodegradation, Environmental
6.
J Med Chem ; 67(11): 8932-8961, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38814290

ABSTRACT

This study developed a class of novel structural antifungal hydrazylnaphthalimidols (HNs) with multitargeting broad-spectrum potential via multicomponent hybridization to confront increasingly severe fungal invasion. Some prepared HNs exhibited considerable antifungal potency; especially nitrofuryl HN 4a (MIC = 0.001 mM) exhibited a potent antifungal activity against Candida albicans, which is 13-fold higher than that of fluconazole. Furthermore, nitrofuryl HN 4a displayed low cytotoxicity, hemolysis and resistance, as well as a rapid fungicidal efficacy. Preliminary mechanistic investigations revealed that nitrofuryl HN 4a could inhibit lactate dehydrogenase to decrease metabolic activity and promote the accumulation of reactive oxygen species, leading to oxidative stress. Moreover, nitrofuryl HN 4a did not exhibit membrane-targeting ability; it could embed into DNA to block DNA replication but could not cleave DNA. These findings implied that HNs are promising as novel structural scaffolds of potential multitargeting broad-spectrum antifungal candidates for treating fungal infection.


Subject(s)
Antifungal Agents , Candida albicans , Microbial Sensitivity Tests , Animals , Humans , Antifungal Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/chemical synthesis , Candida albicans/drug effects , Hemolysis/drug effects , Reactive Oxygen Species/metabolism , Structure-Activity Relationship , Naphthalenes/chemical synthesis , Naphthalenes/chemistry , Naphthalenes/pharmacology , Hydrazines/chemical synthesis , Hydrazines/chemistry , Hydrazines/pharmacology
7.
J Contam Hydrol ; 264: 104338, 2024 May.
Article in English | MEDLINE | ID: mdl-38692145

ABSTRACT

Performance evaluation of in situ bioremediation processes in the field is difficult due to uncertainty created by matrix and contaminant heterogeneity, inaccessibility to direct observation, expense of sampling, and limitations of some measurements. The goal of this research was to develop a strategy for evaluating in situ bioremediation of light nonaqueous-phase liquid (LNAPL) contamination and demonstrating the occurrence of bioenhanced LNAPL dissolution by: (1) integrating a suite of analyses into a rational evaluation strategy; and (2) demonstrating the strategy's application in intermediate-scale flow-cell (ISFC) experiments simulating an aquifer contaminated with a pool of LNAPL (naphthalene dissolved in dodecane). Two ISFCs were operated to evaluate how the monitored parameters changed between a "no bioremediation" scenario and an "intrinsic in situ bioremediation" scenario. Key was incorporating different measures of microbial activity and contaminant degradation relevant to bioremediation: contaminant loss; consumption of electron acceptors; and changes in total alkalinity, pH, dissolved total inorganic carbon, carbon-stable isotopes, microorganisms, and intermediate metabolites. These measurements were integrated via mass-flux modeling and mass-balance analyses to document that in situ biodegradation of naphthalene was strongly accelerated in the "intrinsic in situ bioremediation" scenario versus "no bioremediation." Furthermore, the integrated strategy provided consistent evidence of bioenhancement of LNAPL dissolution through intrinsic bioremediation by a factor of approximately 2 due to the biodegradation of the naphthalene near the pool/water interface.


Subject(s)
Biodegradation, Environmental , Naphthalenes , Water Pollutants, Chemical , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/metabolism , Naphthalenes/chemistry , Naphthalenes/metabolism , Groundwater/chemistry , Alkanes/chemistry , Alkanes/metabolism , Solubility
8.
J Environ Manage ; 361: 121169, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38815425

ABSTRACT

Thermal desorption is a preferred technology for site remediation due to its various advantages. To ensure the effective removal of different pollutants in practical applications, it is necessary to understand the kinetic behaviors and removal mechanisms of pollutants in thermal desorption process. This paper explored the thermal desorption processes of five organic pollutants (nitrobenzene, naphthalene, n-dodecane, 1-nitronaphthalene, and phenanthrene) at 50-350 °C in two different subsoils with 6-18% moisture content. The results suggested that the thermal desorption process was well-fitted by the exponential decay model (R2 = 0.972-0.999) and could be divided into two distinct stages. The first stage was relatively fast and highly influenced by soil moisture, while the second stage showed a slower desorption rate due to the constraints imposed by the soil texture and structure. The influence of soil moisture on thermal desorption depended on the octanol/water partition coefficient (KOW) of pollutants. Pollutants with log KOW values lower than the critical value exhibited enhanced thermal desorption, while those with log KOW values higher than the critical value were inhibited. The critical value of log KOW might be between 3.33 and 4.46. Changes in soil texture and structure caused by heating promoted thermal desorption, especially for naphthalene, 1-nitronaphthalene and phenanthrene. The differences in texture and structure between the two soils diminished as the temperature increased. Finally, an extended kinetic model under changing temperature conditions was derived, and the simulation results for the two subsoils were very close to the actual thermogravimetric results, with the differences ranging from -1.28% to 0.94% and from -0.67% to 1.35%, respectively. These findings propose new insights into the influencing mechanisms of soil moisture and structure on the thermal desorption of organic pollutants. The extended kinetic model can provide reference for future kinetic research and guide practical site remediation.


Subject(s)
Naphthalenes , Soil Pollutants , Soil , Soil Pollutants/chemistry , Kinetics , Soil/chemistry , Naphthalenes/chemistry , Phenanthrenes/chemistry , Environmental Restoration and Remediation/methods
9.
J Am Chem Soc ; 146(21): 14844-14855, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38747446

ABSTRACT

Nature employs sophisticated mechanisms to precisely regulate self-assembly and functions within biological systems, exemplified by the formation of cytoskeletal filaments. Various enzymatic reactions and auxiliary proteins couple with the self-assembly process, meticulously regulating the length and functions of resulting macromolecular structures. In this context, we present a bioinspired, reaction-coupled approach for the controlled supramolecular polymerization in synthetic systems. To achieve this, we employ an enzymatic reaction that interfaces with the adenosine triphosphate (ATP)-templated supramolecular polymerization of naphthalene diimide monomers (NSG). Notably, the enzymatic production of ATP (template) plays a pivotal role in facilitating reaction-controlled, cooperative growth of the NSG monomers. This growth process, in turn, provides positive feedback to the enzymatic production of ATP, creating an ideal reaction-coupled assembly process. The success of this approach is further evident in the living-growth characteristic observed during seeding experiments, marking this method as the pioneering instance where reaction-coupled self-assembly precisely controls the growth kinetics and structural aspects of supramolecular polymers in a predictive manner, akin to biological systems.


Subject(s)
Adenosine Triphosphate , Imides , Naphthalenes , Polymerization , Naphthalenes/chemistry , Naphthalenes/metabolism , Naphthalenes/chemical synthesis , Adenosine Triphosphate/metabolism , Adenosine Triphosphate/chemistry , Imides/chemistry , Macromolecular Substances/chemistry , Macromolecular Substances/metabolism , Macromolecular Substances/chemical synthesis , Molecular Structure , Kinetics , Polymers/chemistry
10.
Phys Chem Chem Phys ; 26(19): 14228-14243, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38690612

ABSTRACT

The development of chromophores that absorb in the near-infrared (NIR) region beyond 1000 nm underpins numerous applications in medical and energy sciences, yet also presents substantial challenges to molecular design and chemical synthesis. Here, the core bacteriochlorin chromophore of nature's NIR absorbers, bacteriochlorophylls, has been adapted and tailored by annulation in an effort to achieve absorption in the NIR-II region. The resulting bacteriochlorin, Phen2,1-BC, contains two annulated naphthalene groups spanning meso,ß-positions of the bacteriochlorin and the 1,2-positions of the naphthalene. Phen2,1-BC was prepared via a new synthetic route. Phen2,1-BC is an isomer of previously examined Phen-BC, which differs only in attachment via the 1,8-positions of the naphthalene. Despite identical π-systems, the two bacteriochlorins have distinct spectroscopic and photophysical features. Phen-BC has long-wavelength absorption maximum (912 nm), oscillator strength (1.0), and S1 excited-state lifetime (150 ps) much different than Phen2,1-BC (1292 nm, 0.23, and 0.4 ps, respectively). These two molecules and an analogue with intermediate characteristics bearing annulated phenyl rings have unexpected properties relative to those of non-annulated counterparts. Understanding the distinctions requires extending concepts beyond the four-orbital-model description of tetrapyrrole spectroscopic features. In particular, a reduction in symmetry resulting from annulation results in electronic mixing of x- and y-polarized transitions/states, as well as vibronic coupling that together reduce oscillator strength of the long-wavelength absorption manifold and shorten the S1 excited-state lifetime. Collectively, the results suggest a heuristic for the molecular design of tetrapyrrole chromophores for deep penetration into the relatively unutilized NIR-II region.


Subject(s)
Porphyrins , Spectroscopy, Near-Infrared , Porphyrins/chemistry , Naphthalenes/chemistry , Molecular Structure , Bacteriochlorophylls/chemistry
11.
Environ Toxicol Chem ; 43(6): 1378-1389, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38661477

ABSTRACT

Octahydro-tetramethyl-naphthalenyl-ethanone (OTNE) is a high-production volume fragrance material used in various down-the-drain consumer products. To assess aquatic risk, the Research Institute for Fragrance Materials (RIFM) uses a tiered data-driven framework to determine a risk characterization ratio, where the ratio of the predicted-environmental concentration to the predicted-no-effect concentration (PNEC) of <1 indicates an acceptable level of risk. Owing to its high production volume and the conservative nature of the RIFM framework, RIFM identified the need to utilize a species sensitivity distribution (SSD) approach to reduce the PNEC uncertainty for OTNE. Adding to the existing Daphnia magna, Danio rerio, and Desmodesmus subspicatus chronic studies, eight new chronic toxicity studies were conducted on the following species: Navicula pelliculosa, Chironomus riparius, Lemna gibba, Ceriodaphnia dubia, Hyalella azteca, Pimephales promelas, Anabaena flos-aquae, and Daphnia pulex. All toxicity data were summarized as chronic 10% effect concentration estimates using the most sensitive biological response. Daphnia magna was the most sensitive (0.032 mg/L), and D. subspicatus was the least sensitive (>2.6 mg/L, the OTNE solubility limit). The 5th percentile hazardous concentration (HC5) derived from the cumulative probability distribution of the chronic toxicity values for the 11 species was determined to be 0.0498 mg/L (95% confidence interval 0.0097-0.1159 mg/L). A series of "leave-one-out" and "add-one-in" simulations indicated the SSD was stable and robust. Add-one-in simulations determined that the probability of finding a species sensitive enough to lower the HC5 two- or threefold was 1/504 and 1/15,300, respectively. Given the high statistical confidence in this robust SSD, an additional application factor protection is likely not necessary. Nevertheless, to further ensure the protection of the environment, an application factor of 2 to the HC5, resulting in a PNEC of 0.0249 mg/L, is recommended. When combined with environmental exposure information, the overall hazard assessment is suitable for a probabilistic environmental risk assessment. Environ Toxicol Chem 2024;43:1378-1389. © 2024 SETAC.


Subject(s)
Naphthalenes , Water Pollutants, Chemical , Animals , Water Pollutants, Chemical/toxicity , Risk Assessment , Naphthalenes/toxicity , Naphthalenes/chemistry , Daphnia/drug effects , Perfume/toxicity , Toxicity Tests, Chronic , Chironomidae/drug effects , Zebrafish , Cladocera/drug effects
12.
Nat Microbiol ; 9(5): 1325-1339, 2024 May.
Article in English | MEDLINE | ID: mdl-38589468

ABSTRACT

Drug-resistant fungal infections pose a significant threat to human health. Dual-targeting compounds, which have multiple targets on a single pathogen, offer an effective approach to combat drug-resistant pathogens, although ensuring potent activity and high selectivity remains a challenge. Here we propose a dual-targeting strategy for designing antifungal compounds. We incorporate DNA-binding naphthalene groups as the hydrophobic moieties into the host defence peptide-mimicking poly(2-oxazoline)s. This resulted in a compound, (Gly0.8Nap0.2)20, which targets both the fungal membrane and DNA. This compound kills clinical strains of multidrug-resistant fungi including Candida spp., Cryptococcus neoformans, Cryptococcus gattii and Aspergillus fumigatus. (Gly0.8Nap0.2)20 shows superior performance compared with amphotericin B by showing not only potent antifungal activities but also high antifungal selectivity. The compound also does not induce antimicrobial resistance. Moreover, (Gly0.8Nap0.2)20 exhibits promising in vivo therapeutic activities against drug-resistant Candida albicans in mouse models of skin abrasion, corneal infection and systemic infection. This study shows that dual-targeting antifungal compounds may be effective in combating drug-resistant fungal pathogens and mitigating fungal resistance.


Subject(s)
Antifungal Agents , Microbial Sensitivity Tests , Antifungal Agents/pharmacology , Antifungal Agents/chemistry , Animals , Mice , Humans , Drug Resistance, Multiple, Fungal , Disease Models, Animal , Cryptococcus neoformans/drug effects , Aspergillus fumigatus/drug effects , Candida albicans/drug effects , Naphthalenes/pharmacology , Naphthalenes/chemistry , Oxazoles/pharmacology , Oxazoles/chemistry , Candida/drug effects , Mycoses/drug therapy , Mycoses/microbiology
13.
J Chromatogr A ; 1722: 464866, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38581976

ABSTRACT

The detection of aromatic aldehydes, considered potential genotoxic impurities, holds significant importance during drug development and production. Current analytical methods necessitate complex pre-treatment processes and exhibit insufficient specificity and sensitivity. This study presents the utilization of naphthalenediimide as a pre-column derivatisation reagent to detect aromatic aldehyde impurities in pharmaceuticals via high-performance liquid chromatography (HPLC). We screened a series of derivatisation reagents through density functional theory (DFT) and investigated the phenomenon of photoinduced electron transfer (PET) for both the derivatisation reagents and the resulting products. Optimal experimental conditions for derivatisation were achieved at 40 °C for 60 min. This approach has been successfully applied to detect residual aromatic aldehyde genotoxic impurities in various pharmaceutical preparations, including 4-Nitrobenzaldehyde, 2-Nitrobenzaldehyde, 1,4-Benzodioxane-6-aldehyde, and 5-Hydroxymethylfurfural. The pre-column derivatisation method significantly enhanced detection sensitivity and reduced the limit of detection (LOD), which ranged from 0.002 to 0.008 µg/ml for the analytes, with relative standard deviations < 3 %. The correlation coefficient (R2) >0.998 demonstrated high quality. In chloramphenicol eye drops, the concentration of 4-Nitrobenzaldehyde was measured to be 8.6 µg/mL below the specified concentration, with recoveries ranging from 90.0 % to 119.2 %. In comparison to existing methods, our work simplifies the pretreatment process, enhances the sensitivity and specificity of the analysis, and offers comprehensive insights into impurity detection in pharmaceutical preparations.


Subject(s)
Aldehydes , Drug Contamination , Imides , Limit of Detection , Naphthalenes , Chromatography, High Pressure Liquid/methods , Naphthalenes/chemistry , Naphthalenes/analysis , Aldehydes/analysis , Aldehydes/chemistry , Imides/chemistry , Mutagens/analysis , Mutagens/chemistry , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/analysis , Benzaldehydes/chemistry , Benzaldehydes/analysis
14.
Anal Chim Acta ; 1305: 342582, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38677838

ABSTRACT

BACKGROUND: Detecting and neutralizing Pd2+ ions are a significant challenge due to their cytotoxicity, even at low concentrations. To address this issue, various chemosensors have been designed for advanced detection systems, offering simplicity and the potential to differentiate signals from different analytes. Nonetheless, these chemosensors often suffer from limited emission response and complex synthesis procedures. As a result, the tracking and quantification of residual palladium in biological systems and environments remain challenging tasks, with only a few chemosensing probes available for commercial use. RESULTS: In this paper, a straightforward approach for the selective detection of Pd2+ ions is proposed, which involves the design, synthesis, and utilization of a propargylated naphthalene-derived probe (E)-N'-((2-(prop-2-yn-1-yloxy)naphthalen-1-yl)methylene)benzohydrazide (NHP). The NHP probe exhibits sensitive dual-channel colorimetry and fluorescence Pd2+ detection over other tested metal ions. The detection process is performed through a catalytic depropargylation reaction, followed by an excited state intramolecular proton transfer (ESIPT) process, the detection limit is as low as 11.58 × 10-7 M under mild conditions. Interestingly, the resultant chemodosimeter adduct (E)-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (NHH) was employed for the consecutive detection of CN- ions, exhibiting an impressive detection limit of 31.79 × 10-8 M. Validation of both detection processes was achieved through 1H nuclear magnetic resonance and density functional theory calculations. For real-time applications of the NHP and NHH probes, smartphone-assisted detection, and intracellular detection of Pd2+ and CN- ions within HeLa cells were studied. SIGNIFICANCE: This research presents a novel naphthalene derivative for visually detecting environmentally toxic Pd2+ and CN- ions. The synthesized probe selectively binds to Pd2+, forming a chemodosimeter. It successfully detects CN- ions through colorimetry and fluorimetry, offering a low detection limit and quick response. Notably, it's the first naphthalene-based small molecule to serve as a dual probe for toxic analytes - palladium and cyanide. Moreover, it effectively detects Pd2+ and CN- intracellularly in cancer cells.


Subject(s)
Fluorescent Dyes , Palladium , Palladium/chemistry , Humans , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Cyanides/analysis , Naphthalenes/chemistry , Naphthalenes/toxicity , HeLa Cells , Optical Imaging , Limit of Detection , Colorimetry/methods , Molecular Structure , Spectrometry, Fluorescence
15.
Biochemistry (Mosc) ; 89(3): 407-416, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38648761

ABSTRACT

The synthesis of (p)ppGpp alarmones plays a vital role in the regulation of metabolism suppression, growth rate control, virulence, bacterial persistence, and biofilm formation. The (p)ppGpp alarmones are synthesized by proteins of the RelA/SpoT homolog (RSH) superfamily, including long bifunctional RSH proteins and small alarmone synthetases. Here, we investigated enzyme kinetics and dose-dependent enzyme inhibition to elucidate the mechanism of 4-(4,7-dimethyl-1,2,3,4-tetrahydronaphthalen-1-yl)pentanoic acid (DMNP) action on the (p)ppGpp synthetases RelMsm and RelZ from Mycolicibacterium smegmatis and RelMtb from Mycobacterium tuberculosis. DMNP was found to inhibit the activity of RelMtb. According to the enzyme kinetics analysis, DMNP acts as a noncompetitive inhibitor of RelMsm and RelZ. Based on the results of molecular docking, the DMNP-binding site is located in the proximity of the synthetase domain active site. This study might help in the development of alarmone synthetase inhibitors, which includes relacin and its derivatives, as well as DMNP - a synthetic analog of the marine coral metabolite erogorgiaene. Unlike conventional antibiotics, alarmone synthetase inhibitors target metabolic pathways linked to the bacterial stringent response. Although these pathways are not essential for bacteria, they regulate the development of adaptation mechanisms. Combining conventional antibiotics that target actively growing cells with compounds that impede bacterial adaptation may address challenges associated with antimicrobial resistance and bacterial persistence.


Subject(s)
Bacterial Proteins , Ligases , Mycobacterium tuberculosis , Bacterial Proteins/metabolism , Bacterial Proteins/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry , Kinetics , Ligases/antagonists & inhibitors , Ligases/metabolism , Molecular Docking Simulation , Mycobacterium smegmatis/enzymology , Mycobacterium smegmatis/drug effects , Mycobacterium tuberculosis/enzymology , Mycobacterium tuberculosis/drug effects , Naphthalenes/pharmacology , Naphthalenes/chemistry , Diterpenes/pharmacology
16.
Phytochemistry ; 222: 114073, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38565420

ABSTRACT

Two undescribed cladosporol derivatives, cladosporols J-K (1-2), and three previously unreported spirobisnaphthalenes, urnucratins D-F (3-5), as well as eleven known cladosporols (6-16), were characterized from Cladosporium cladosporioides (Cladosporiaceae), a common plant pathogen isolated from the skin of Chinese toad. Cladosporols J-K (1-2) with a single double bond have been rarely reported, while urnucratins D-F (3-5) featured an unusual benzoquinone bisnaphthospiroether skeleton, contributing to an expanding category of undiscovered natural products. Their structures and absolute configurations were determined using extensive spectroscopic methods, including NMR, HRESIMS analyses, X-ray single crystal diffraction, as well as through experimental ECD analyses. Biological assays revealed that compounds 1 and 2 exhibited inhibitory activity against A549 cells, with IC50 values of 30.11 ± 3.29 and 34.32 ± 2.66 µM, respectively.


Subject(s)
Cladosporium , Naphthalenes , Cladosporium/chemistry , Humans , Naphthalenes/chemistry , Naphthalenes/isolation & purification , Naphthalenes/pharmacology , Molecular Structure , Drug Screening Assays, Antitumor , A549 Cells , Spiro Compounds/chemistry , Spiro Compounds/isolation & purification , Spiro Compounds/pharmacology , Structure-Activity Relationship , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/isolation & purification , Dose-Response Relationship, Drug , Cell Proliferation/drug effects
17.
J Asian Nat Prod Res ; 26(5): 555-561, 2024 May.
Article in English | MEDLINE | ID: mdl-38563409

ABSTRACT

A newly discovered trihydroxynaphthalenone derivative, epoxynaphthalenone (1) involving the condensation of ortho-hydroxyl groups into an epoxy structure, and a novel pyrone metabolite characterized as pyroneaceacid (2), were extracted from Talaromyces purpurpgenus, an endophytic fungus residing in Rhododendron molle. The structures of these compounds were elucidated through a comprehensive analysis of their NMR and HRESIMS data. The determination of absolute configurations was accomplished using electronic circular dichroism (ECD) calculations and CD spectra. Notably, these recently identified metabolites exhibited a moderate inhibitory activity against xanthine oxidase (XOD).


Subject(s)
Pyrones , Talaromyces , Xanthine Oxidase , Talaromyces/chemistry , Molecular Structure , Pyrones/chemistry , Pyrones/pharmacology , Pyrones/isolation & purification , Xanthine Oxidase/antagonists & inhibitors , Nuclear Magnetic Resonance, Biomolecular , Naphthalenes/chemistry , Naphthalenes/isolation & purification , Naphthalenes/pharmacology , Circular Dichroism
18.
Angew Chem Int Ed Engl ; 63(23): e202401250, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38576254

ABSTRACT

A nano-immunomodulator (R-NPT NP) comprising a tumor microenvironment (TME) activable resiquimod (R848) and a π-extended NIR-absorbing naphthophenanthrolinetetraone (NPT) has been engineered for spatiotemporal controlled photothermal immunotherapy. R-NPT NP demonstrated excellent photostability, while R848 promoted synergistic immunity as a toll-like receptor 7/8 (TLR7/8) agonist. Upon accumulation at the tumor site, R-NPT NP released R848 in response to redox metabolite glutathione (GSH), triggering dendritic cell (DC) activation. The photothermal effect endowed by R-NPT NP can ablate tumors directly and trigger immunogenic cell death to augment immunity after photoirradiation. The synergistic effect of GSH-liable TLR7/8 agonist and released immunogenic factors leads to a robust evocation of systematic immunity through promoted DC maturation and T cell infiltration. Thus, R-NPT NP with photoirradiation achieved 99.3 % and 98.2 % growth inhibition against primary and distal tumors, respectively.


Subject(s)
Imides , Immunologic Factors , Immunotherapy , Naphthalenes , Immunologic Factors/chemistry , Immunologic Factors/pharmacology , Humans , Naphthalenes/chemistry , Naphthalenes/pharmacology , Imides/chemistry , Imides/pharmacology , Animals , Nanoparticles/chemistry , Mice , Tumor Microenvironment/drug effects , Photothermal Therapy , Imidazoles/chemistry , Imidazoles/pharmacology , Dendritic Cells/drug effects , Dendritic Cells/immunology , Cell Line, Tumor
19.
Angew Chem Int Ed Engl ; 63(23): e202401979, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38581278

ABSTRACT

Spirobisnaphthalenes (SBNs) are a class of highly oxygenated, fungal bisnaphthalenes containing a unique spiroketal bridge, that displayed diverse bioactivities. Among the reported SBNs, palmarumycins are the major type, which are precursors for the other type of SBNs structurally. However, the biosynthesis of SBNs is unclear. In this study, we elucidated the biosynthesis of palmarumycins, using gene disruption, heterologous expression, and substrate feeding experiments. The biosynthetic gene cluster for palmarumycins was identified to be distant from the polyketide synthase gene cluster, and included two cytochrome P450s (PalA and PalB), and one short chain dehydrogenase/reductase (PalC) encoding genes as key structural genes. PalA is an unusual, multifunctional P450 that catalyzes the oxidative dimerization of 1,8-dihydroxynaphthalene to generate the spiroketal linkage and 2,3-epoxy group. Chemical synthesis of key intermediate and in vitro biochemical assays proved that the oxidative dimerization proceeded via a binaphthyl ether. PalB installs the C-5 hydroxy group, widely found in SBNs. PalC catalyzes 1-keto reduction, the reverse 1-dehydrogenation, and 2,3-epoxide reduction. Moreover, an FAD-dependent oxidoreductase, encoded by palD, which locates outside the cluster, functions as a 1-dehydrogenase. These results provided the first genetic and biochemical evidence for the biosynthesis of palmarumycin SBNs.


Subject(s)
Naphthalenes , Spiro Compounds , Spiro Compounds/metabolism , Spiro Compounds/chemistry , Naphthalenes/metabolism , Naphthalenes/chemistry , Cytochrome P-450 Enzyme System/metabolism , Cytochrome P-450 Enzyme System/genetics , Multigene Family , Oxidoreductases/metabolism , Oxidoreductases/genetics , Oxidoreductases/chemistry
20.
Anal Chem ; 96(16): 6467-6475, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38602368

ABSTRACT

Room temperature phosphorescence (RTP) nanoprobes play crucial roles in hypoxia imaging due to their high signal-to-background ratio (SBR) in the time domain. However, synthesizing RTP probes in aqueous media with a small size and high quantum yield remains challenging for intracellular hypoxic imaging up to present. Herein, aqueous RTP nanoprobes consisting of naphthalene anhydride derivatives, cucurbit[7]uril (CB[7]), and organosilicon are reported via supermolecular confined methods. Benefiting from the noncovalent confinement of CB[7] and hydrolysis reactions of organosilicon, such small-sized RTP nanoprobes (5-10 nm) exhibit inherent tunable phosphorescence (from 400 to 680 nm) with microsecond second lifetimes (up to ∼158.7 µs) and high quantum yield (up to ∼30%). The as-prepared RTP nanoprobes illustrate excellent intracellular hypoxia responsibility in a broad range from ∼0.1 to 21% oxygen concentrations. Compared to traditional fluorescence mode, the SBR value (∼108.69) of microsecond-range time-resolved in vitro imaging is up to 2.26 times greater in severe hypoxia (<0.1% O2), offering opportunities for precision imaging analysis in a hypoxic environment.


Subject(s)
Heterocyclic Compounds, 2-Ring , Imidazoles , Imidazolidines , Macrocyclic Compounds , Humans , Imidazoles/chemistry , Silicon/chemistry , Nanoparticles/chemistry , Cell Hypoxia , Bridged-Ring Compounds/chemistry , Optical Imaging , Fluorescent Dyes/chemistry , Luminescent Measurements , Naphthalenes/chemistry , Time Factors , HeLa Cells
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