Methoxy Moiety Research Articles

The role of hydrogen bonding in the conformational stability of 2-methoxyresorcinol: Insights from theoretical calculations, SERS spectroscopy, and solvent effect

Resorcinol derivatives exhibit unique structural and electronic features. The presence of two hydroxyl groups, along with other substituents, can greatly impact these molecules’ conformational profile and vibrational characteristics. This work investigates molecular and electronic properties of 2-methoxyresorcinol (2-MR) by combining quantum-chemical and spectroscopic techniques. The molecule of 2-MR can exist in the syn, anti, and anti–syn configurations, depending on the orientation of the hydroxyl groups. The syn and anti–syn forms have been verified from DFT, MP2 and MP4 (SDQ) calculations and from infrared/Raman spectroscopy to be stabilized by intramolecular hydrogen bonding that takes place between the hydrogen atoms of the OH groups and the methoxy moiety’s oxygen atom. Such an interaction results in 6–7 kcal/mol more stable states than the corresponding anti-configuration, where only steric forces control the molecule stability. The effect of different solvents on the Raman features has also been accessed. Unlike other solutions, aqueous 2-MR facilitated a split in the OH stretching peak, which can be attributed to the pronounced solute–solvent intermolecular forces through the OH groups. Surface-enhanced Raman scattering (SERS) spectroscopic analysis of trace 2-MR utilizing as-synthesized silver nanoparticles shows a remarkable boost in the Raman signal intensities of several vibrational modes. The SERS detection exhibits a wide dynamic range and a detection limit of 1 × 10−8 M.

Investigating the antioxidant potential and mechanism of a hydrazide bioactive component of garlic: insights from density functional theory calculations, drug-likeness and molecular docking studies.

Glutathione remains one of the most efficient antioxidant compounds in living systems, and the biological abilities of hydrazides have been well documented in literature. This study highlights the phytochemical constituents of garlic and the separation of the bioactive benzoic acid, 4-chloro- 1-(4-methoxyphenyl) hydrazide (BA4C) using gas chromatography-mass spectroscopy (GC-MS) technique. Preliminary phytochemical screening reveals the presence of alkaloids, saponins, flavonoids, tannins, terpenoids, steroids and phenols. Computationally, compound BA4C was optimized using the B3LYP/aug-cc-PVDZ DFT method. Spectroscopic studies of the compound involved analysis of the vibrational FT-IR frequencies and the modes of vibrations. Frontier molecular orbitals analysis records an energy gap of 4.3391eV; NBO studies reveal that the compound has strong perturbation energies of 246kcal/mol and 269kcal/mol among its intramolecular interactions such as *C12 - C13 to *C14 - C15 and *C11 - C16 to *C14 - C15, respectively. According to the visualization of non-covalent interactions, steric repulsions were observed at the core of the phenyl and benzene rings. However, other regions of the compound depict a significant balance of forces between steric repulsions and van der Waals forces. To significantly deduce the reducing power of compound BA4C, electrons were found to be highly localized at the methoxy and hydrazide moieties significantly implying their propensity to donate electrons to oxidized systems. Furthermore, ADMET analysis reveals that the compound has two hydrogen donors. Most significantly, the compound binds to NADPH dehydrogenase (5V4P) and glutathione reductase (1XAN) with binding energies of - 6.0kcal/mol and - 8.0kcal/mol showing considerable favourable binding feasibility as well as forming plural hydrogen bonds with the amino acid residues. Notably, BA4C was bonded at the active site of 1XAN, which implies the ability of the compound for the reduction of oxidized glutathione.

A Class of Heptaphyrins with NIR Absorption Modulated by Metal Coordination and Nucleophilic Substitution.

The intensive interest in expanded porphyrins can be attributed to their appealing photoelectric and coordination behavior. In this work, an N-confused heptaphyrin 1 was synthesized by an acid-catalyzed [3+4] condensation reaction. The introduction of an N-confused pyrrolic unit into the heptaphyrin macrocycle led to the formation of a figure-eight-like conformation with nonsymmetrical "NNNN" and "NNNC" coordination cavities employable for bimetallic coordination. As a result, chelation of 1 with Zn(II) and Cu(II) afforded mono-Zn(II) complex 2 and bis-Cu(II) complex 3, respectively, with the metal atoms exhibiting distorted square-planar geometries. In complex 3, an oxygen atom is attached to the α-C atom of N-confused pyrrole D, and thus the N and C atoms of ring D participate in coordination within the two cavities. Interestingly, treatment of 1 with Cs2CO3 in MeOH resulted in regioselective substitution of all the seven para-F atoms in the meso-C6F5 groups as well as the α-H of ring D by eight methoxy moieties. Complex 3 displays a red-shifted absorption band edge of ca. 2200 nm, compared to that of ca. 1600 nm observed for 1. This work provides an example of incorporating an N-confused pyrrole to construct expanded porphyrins with distinctive coordination behavior and tunable NIR absorption.

Direct synthesis, characterization, in vitro and in silico studies of simple chalcones as potential antimicrobial and antileishmanial agents.

Chalcone represents a vital biosynthetic scaffold owing to its numerous therapeutic effects. The present study was intended to synthesize 17 chalcone derivatives (3a-q) by direct coupling of substituted acetophenones and benzaldehyde. The target chalcones were characterized by spectroscopic analyses followed by their in vitro antimicrobial, and antileishmanial investigations with reference to standard drugs. The majority of the chalcones displayed good to excellent biological activities. Chalcone 3q (1000 µg ml-1) exhibited the most potent antibacterial effect with its zone of inhibition values of 30, 33 and 34 mm versus Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa respectively. The results also confirmed chalcone 3q to be the most potent versus Leishmania major with the lowest IC50 value of 0.59 ± 0.12 µg ml-1. Chalcone 3i (500 µg ml-1) was noticed to be the most potent antifungal agent with its zone of inhibition being 29 mm against Candida albicans. Computational studies of chalcones 3i and 3q supported the preliminary in vivo results. The existence of the amino moiety and bromine atom on ring-A and methoxy moieties on ring-B caused better biological effects of the chalcones. In brief, the investigations reveal that chalcones (3i and 3q) can be employed as building blocks to discover novel antimicrobial agents.

Ultra-high signal-to-noise ratio near-infrared chemiluminescent probe for in vivo sensing singlet oxygen

Singlet oxygen (1O2), as the primary reactive oxygen species in photodynamic therapy, can effectively induce excessive oxidative stress to ablate tumors and kill germs in clinical treatment. However, monitoring endogenous 1O2 is greatly challenging due to its extremely short lifetime and high reactivity in biological condition. Herein, we report an ultra-high signal-to-ratio near-infrared chemiluminescent probe (DCM-Cy) for the precise detection of endogenous 1O2 during photodynamic therapy (PDT). The methoxy moiety was removed from enolether unit in DCM-Cy to suppress the potential self-photooxidation reaction, thus greatly eliminating the photoinduced background signals during PDT. Additionally, the compact cyclobutane modification of DCM-Cy resulted in a significant 6-fold increase in cell permeability compared to conventional adamantane-dioxane probes. Therefore, our “step-by-step” strategy for DCM-Cy addressed the limitations of traditional chemiluminescent (CL) probes for 1O2, enabling effectively tracking of endogenous 1O2 level changes in living cells, pathogenic bacteria and mice in PDT.

Sodium fluoride enables room-temperature synthesis of dimethyl carbonate

Carbon dioxide (CO2) in the atmosphere of the Earth represents an abundant and largely free source of carbon, which remains heavily underestimated nowadays. The disbalance between the emission and utilization of CO2 puts the sustainable development of humanity at risk because of its possible correlation with global climate change. The valorization of CO2 is an important strategy to attend to the above-mentioned challenges. CO2 can be converted to dimethyl carbonate by grafting to methanol (CH3OH) in the presence of the catalyst. The presently known catalytic solutions require high temperatures and pressures to be employed. Herein, we report sodium fluoride as a new catalyst offering an unprecedentedly low activation barrier, 23 kJ/mol, for the carboxylation of CH3OH. The fluoride anion coordinates the hydroxyl hydrogen of CH3OH thanks to forming a very strong H-bond. Upon the collision with CO2, the proton detaches, and CO2 grafts to CH3O* while becoming the carboxyl group. The reaction finishes by methylating CH3OC(O)O– via the methyl radical originating from another CH3OH molecule (esterification stage). The hydrogen fluoride molecule is an intermediate in this reaction providing the proton and fostering esterification. The subsequent in-lab experiments showed that much milder conditions can be used to synthesize DMC out of CH3OH. Under 80 °C and 40 bar, we obtained an outstanding DMC yield of 21.1 %. However, the synthesis was also possible at lower temperatures giving DMC yields of 16.3 % at 65 °C, 14.7 % at 55 °C, and 10.8 % at 25 °C. The unprecedented possibility to obtain a non-negligible production of an organic carbonate at room temperature represents a cornerstone advance in the field of CO2 valorization and promises huge energy savings. Given the current global amount of the yearly prepared DMC amounting to over one million tons and the demand for this chemical by emerging chemical technologies, the achieved result is deemed to be of paramount importance. The exemplified catalytic mechanism is also interesting in the context of other syntheses, in which a low-energetic production of the methoxy moieties is a cornerstone.

Synthesis, mesomorphic and magnetic properties at room temperature of biphenyl ester-aromatic imine with terminal alkoxy chains and methoxy substituent

ABSTRACT A series of calamitic biphenyl ester-aromatic imine derived from the reaction of 4-formylphenyl-4’-(alkyloxy)-[1,1’-biphenyl]-4-carboxylate and p-anisidine have been successfully synthesised and characterised. The general molecular structures of ultimate compounds show the central fragment made up by a hybrid core of biphenyl ester-aromatic imine in which the terminal alkoxy chains, CnH2n + 1 in which n = 7–12 were connected to biphenyl while the other end consists of methoxy moiety attached to a phenyl ring. All the target compounds under polarised lights exhibit enantiotropic nematic phase of which the temperature range was further supported by DSC analysis. It can be summarised that the lengthening of terminal alkoxy chains has contributed to the lowering of melting and clearing temperatures as well as the thermal stability of nematic phase. A dedicated magnetic characterisation analysis disclosed that apart from a dominant diamagnetic character these compounds possess a noticeable magnetic interaction despite knowing that the compounds belong to the non-metal and non-radical containing species.

Oligodeoxynucleotide Synthesis Under Non-Nucleophilic Deprotection Conditions.

This protocol describes a method for the incorporation of sensitive functional groups into oligodeoxynucleotides (ODNs). The nucleophile-sensitive epigenetic N4-acetyldeoxycytosine (4acC) DNA modification is used as an example, but other sensitive groups can also be incorporated, e.g., alkyl halide, α-haloamide, alkyl ester, aryl ester, thioester, and chloropurine groups, all of which are unstable under the basic and nucleophilic deprotection and cleavage conditions used in standard ODN synthesis methods. The method uses a 1,3-dithian-2-yl-methoxycarbonyl (Dmoc) group that carries a methyl group at the carbon of the methoxy moiety (meDmoc) for the protection of exo-amines of nucleobases. The growing ODN is anchored to a solid support via a Dmoc linker. With these protecting and linking strategies, ODN deprotection and cleavage are achieved without using any strong bases and nucleophiles. Instead, they can be carried out under nearly neutral non-nucleophilic oxidative conditions. To increase the length of ODNs that can be synthesized using the meDmoc method, the protocol also describes the synthesis of a PEGylated Dmoc (pDmoc) phosphoramidite. With some of the nucleotides being incorporated with pDmoc-CE phosphoramidite, the growing ODN on the solid support carries PEG moieties and becomes more soluble, thus enabling longer ODN synthesis. The ODN synthesis method described in this protocol is expected to make many sensitive ODNs that are difficult to synthesize accessible to researchers in multiple areas, such as epigenetics, nanopore sequencing, nucleic acid-protein interactions, antisense drug development, DNA alkylation carcinogenesis, and DNA nanotechnology. © 2024 Wiley Periodicals LLC. Basic Protocol: Sensitive ODN synthesis Support Protocol 1: Synthesis of meDmoc-CE phosphoramidites Support Protocol 2: Synthesis of a pDmoc-CE phosphoramidite.

Supramolecular assembly involving weak hydrogen bonds, anti-parallel π···π stacking and O···C tetrel bonding interactions and LOX studies in a 1H-pyrazol-1-yl)thiazole-4-carboxylate derivative: An experimental and theoretical study

In this manuscript, we synthesized a novel ethyl 2-(5-(4-methoxyphenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole-4-carboxylate (5) from the reaction acetophenone with 3-methoxybenzaldehyde in basic condition to afford the chalcone derivative (3) which has ability to cyclized with thiosemicarbazide to afford the corresponding dihydro-1H-pyrazole-1-carbothioamide (4). Compound 4 easily reacts with ethyl-3‑bromo-2-oxopropanoate to give the ethyl-2-(5-(3-methoxyphenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole-4-carboxylate (5). The structure of the synthesized compound was confirmed through spectral analysis (FT-IR, 1HNMR, 13CNMR). Moreover, the crystal structure of compound (5) has been solved using single-crystal X-ray diffraction measurements. These results indicate that 5 crystallizes in the monoclinic crystal system in the P21/n space group. The solid-state structure is mainly stabilized by a combination of intermolecular interactions such as weak hydrogen bonds, CH···π, π···π stacking and O···C tetrel bonding interactions involving the O-atom of the ester group and the C-atom of the methoxy moiety. In order to confirm the presence of the mentioned intermolecular contacts, we have performed Hirshfeld surface analysis and their associated two-dimensional fingerprint plots. In addition, the strength and nature of the intermolecular interactions have been evaluated by using different computational tools including QTAIM and NCIplot index analysis. Molecular docking analysis was performed with both the enantiomers of pyrazolyl thiazole carboxylate and it was found that 1R bounds deeply into the pocket than 1S, furthermore 1R and indomethacin forms hydrogen bonds while 1S do not. The Molecular results are in good agreement with the experimental data

Label-Free Quantification of Digital Nanorods Assembled from Discrete Oligourethane Amphiphiles.

Polymeric nanoparticles (NPs) have been extensively designed for theranostic agent delivery. Previous methods for tracking their biological behavior and assessing theranostic efficacy heavily rely on fluorescence or isotope labeling. However, these labeling techniques may alter the physicochemical properties of the labeled NPs, leading to inaccurate biodistribution information. Therefore, it is highly desirable to develop label-free techniques for accurately assessing the biological fate of polymeric NPs. Here, we create discrete oligourethane amphiphiles (DOAs) with methoxy (OMe), hydroxyl (OH), and maleimide (MI) moieties at the dendritic oligo(ethylene glycol) (dOEG) ends. We obtained four types of digital nanorods (NRs) with distinct surface functional groups through self-assembly of a single DOA (OMe and OH NRs) or coassembly of two DOAs (OMe-MI and OH-MI NRs). These unique NRs can be directly quantified in a label-free manner by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Specifically, OMe-MI NRs exhibited the best blood circulation, and OH-MI showed the highest area under the curve (AUC) value after intravenous injection. Biodistribution studies demonstrated that MI-containing NRs generally had lower accumulation in the liver and spleen compared to that of MI-free NRs, except for the comparison between OMe and OMe-MI NRs in the liver. Proteomics studies unveiled the formation of distinct protein coronas that may greatly affect the biological behavior of NRs. This study not only provides a label-free technique for quantifying the pharmacokinetics and biodistribution of polymeric NRs but also highlights the significant impact of surface functional groups on the biological fate of polymeric NPs.

Structural and computational insights into the regioselectivity of SpnK involved in rhamnose methylation of spinosyn

Rhamnose methylation of spinosyn critical for insecticidal activity is orchestrated by substrate specificity of three S-adenosyl-L-methionine (SAM) dependent methyltransferases (MTs). Previous in vitro enzymatic assays indicate that 3′-O-MT SpnK accepts the rhamnosylated aglycone (RAGL) and 2′-O-methylated RAGL as substrates, but does not tolerate the presence of a methoxy moiety at the O-4′ position of the rhamnose unit. Here we solved the crystal structures of apo and ligand-bound SpnK, and used molecular dynamic (MD) simulations to decipher the molecular basis of substrate specificity. SpnK assembles into a tetramer, with each set of three monomers forming an integrated substrate binding pocket. The MD simulations of SpnK complexed with RAGL or 2′-O-methylated RAGL revealed that the 4′-hydroxyl of the rhamnose unit formed a hydrogen bond with a conserved Asp299 of the catalytic center, which is disrupted in structures of SpnK complexed with 4′-O-methylated RAGL or 2′,4′-di-O-methylated RAGL. Comparison with SpnI methylating the C2′-hydroxyl of RAGL reveals a correlation between a DLQT/DLWT motif and the selectivity of rhamnose O-MTs. Together, our structural and computational results revealed the structural basis of substrate specificity of rhamnose O-MTs and would potentially help the engineering of spinosyn derivatives.

Synthesis and Evaluation of Acetylcholinesterase Inhibitory and Cytotoxic Activities of Pyrano[2,3-d]pyrimidines

Objective: The study was conducted to evaluate the in vitro acetylcholinesterase (AchE) inhibition activity of novel pyrano[2,3- d]pyrimidine derivatives. Methods: A series of new pyrano[2,3- d]pyrimidine derivatives were synthesized in moderate to good yields (63%-81%) by using microwave-prompted “one-pot” two-step multicomponent reactions of cyclohexane-1,3-dione, malononitrile, aldehydes, and acetic anhydride. Noticeably, Diazabicyclo[2.2.2]octane was successfully employed as a basic catalyst for the formation of 2-amino-4H-pyran-3-carbonitrile intermediates. These products were identified using spectral data, and assessed in terms of their AChE inhibition activity and cytotoxicity against three types of human cancer cell lines including epidermoid carcinoma (KB), hepatoma carcinoma (HepG2), and non-small lung cancer (A549) cell lines. Results: Most of the products depicted moderate to good AChE inhibitory activity, among them, one product with methoxy moiety at meta-position on phenyl group showed the best AchE inhibition activity with IC50 values of 2.20 ± 0.17 µg/mL. Moreover, products exhibited no cytotoxicity against cancer cell lines. Conclusion: This study highlighted that pyrano[2,3- d]pyrimidine derivatives as promising candidates for further investigations directed to the discovery of new AChE inhibitors which could be used in Alzheimer's disease therapy.

Two-Photon Absorption Response of Functionalized BODIPY Dyes in Near-IR Region by Tuning Conjugation Length and Meso-Substituents.

BODIPY dyes substituted by phenol or -COOMe units at the meso-position (C8) with and without a distyryl group including a methoxy moiety at the -C3 and -C5 positions of the BODIPY have been synthesized to analyze the photophysical properties. To clarify the ground-state interaction, absorption and emission features were investigated in the THF environment. Extending the π-conjugation with the methoxy moiety at -C3 and -C5 positions of BODIPY leads to a spectral shifting of the absorption maxima toward red by 120 nm. In addition, attaching the -COOMe unit at the meso-position of the BODIPY structure increases nonradiative molecular relaxation as compared to compounds possessing phenol substituents at the same position. We have investigated the effect of phenol and a -COOMe group and π-extended conjugation length with a methoxy moiety on the properties of two-photon absorption (TPA) and electron transfer dynamics by performing open-aperture (OA) Z-scan and femtosecond transient absorption spectroscopy measurements, respectively. The synthesized BODIPY compounds with the distyryl group including the methoxy unit show TPA character due to the longer conjugation length and therefore intramolecular charge transfer ability. Based on the OA Z-scan experiments upon photoexcitation with 800 nm pulsed laser light, TPA cross-section values were obtained as 74 and 81 GM for the compounds possessing phenol and -COOMe units at the meso-position of BODIPY treated by distyryl group with methoxy moieties, respectively. Additionally, optical and electronic properties were calculated theoretically by using the DFT method.

UV-Vis spectroscopic and colorimetric anion detection and fluorescence properties of new 3-amino-4-hydroxybenzenesulfonic acid-based Schiff bases depending on the strength and position of the electron donor substitution

In this study, 3-amino-4-hydroxybenzenesulfonic acid-based imine compounds; 3-(2,5-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (1), 3-(2,4-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (2) and 4-hydroxy-3-(2-hydroxy-3-methoxybenzylideneamino)-4-hydroxybenzenesulfonic acid (3) was synthesized. The compounds were analyzed using various spectroscopy methods, and the experimental UV–vis data matched the theoretical predictions. The compound 1 displayed lower stability, higher reactivity, and easier photoexcitation due to a smaller HOMO-LUMO energy gap. The investigated compounds 1-3 showed promise as chemosensors for anions, providing visible detection in daylight conditions. The compound 3 exhibited selective fluorescence at specific wavelengths. The compounds 1-3 interacted with DNA through electrostatic interactions. Also, compounds 1-3 showed higher antioxidant activity than BHT. However, fluorescence measurements indicated that the emission signals were strongly influenced by the position and strength of the electron-donating group. Adding a hydroxy or methoxy moiety near the -OH group on the phenyl ring decreased the fluorescence signal due to intersystem crossing and intramolecular charge transfer mechanisms, respectively. These findings were supported by femtosecond transient absorption spectroscopy measurements. The results emphasize the significance of substituents in imines derived from 3-amino-4-hydroxybenzenesulfonic acid in determining their biological activities, as well as their optical and sensor properties.

Experimental IR, Raman, and UV-Vis Spectra DFT Structural and Conformational Studies: Bioactivity and Solvent Effect on Molecular Properties of Methyl-Eugenol.

Structural, conformational, and spectroscopic investigations of methyl-eugenol were made theoretically at the B3LYP-6-311++G**level. Experimental IR, Raman, and UV-vis spectra were investigated and analyzed in light of the computed quantities. Conformational analysis was carried out with the help of total energy vs. dihedral angle curves for different tops, yielding 21 stable conformers, out of which only two have energies below the room temperature relative to the lowest energy conformer. The effect of the solvent on different molecular characteristics was investigated theoretically. MEP and HOMO-LUMO analysis were carried out and barrier heights and bioactivity scores were determined. The present investigation suggests that the molecule has three active sites with moderate bioactivity. The solvent-solute interaction is found to be dominant in the vicinity of the methoxy moieties.

Simple Coumarins from Peucedanum luxurians Fruits: Evaluation of Anxiolytic Activity and Influence on Gene Expression Related to Anxiety in Zebrafish Model.

Anxiety is one of the most common central nervous system disorders, affecting at least one-quarter of the worldwide population. The medications routinely used for the treatment of anxiety (mainly benzodiazepines) are a cause of addiction and are characterized by many undesirable side effects. Thus, there is an important and urgent need for screening and finding novel drug candidates that can be used in the prevention or treatment of anxiety. Simple coumarins usually do not show side effects, or these effects are much lower than in the case of synthetic drugs acting on the central nervous system (CNS). This study aimed to evaluate the anxiolytic activity of three simple coumarins from Peucedanum luxurians Tamamsch, namely officinalin, stenocarpin isobutyrate, and officinalin isobutyrate, in a 5 dpf larval zebrafish model. Moreover, the influence of the tested coumarins on the expression of genes involved in the neural activity (c-fos, bdnf) or dopaminergic (th1), serotoninergic (htr1Aa, htr1b, htr2b), GABA-ergic (gabarapa, gabarapb), enkephalinergic (penka, penkb), and galaninergic (galn) neurotransmission was assessed by quantitative PCR. All tested coumarins showed significant anxiolytic activity, with officinalin as the most potent compound. The presence of a free hydroxyl group at position C-7 and the lack of methoxy moiety at position C-8 might be key structural features responsible for the observed effects. In addition, officinalin and its isobutyrate upregulated the expression of genes involved in neurotransmission and decreased the expression of genes connected with neural activity. Therefore, the coumarins from P. luxurians might be considered as promising drug candidates for the therapy of anxiety and related disorders.

Amelioration of lipopeptide biosurfactants for enhanced antibacterial and biocompatibility through molecular antioxidant property by methoxy and carboxyl moieties

Biosurfactants having surface-active biomolecules have been the cynosure in environment research due to their vast application. However, the lack of information about their low-cost production and detailed mechanistic biocompatibility limits the applicability. The study explores techniques for the production and design of low-cost, biodegradable, and non-toxic biosurfactants from Brevibacterium casei strain LS14 and excavates the mechanistic details of their biomedical properties like antibacterial effects and biocompatibility. Taguchi’s design of experiment was used to optimize for enhancing biosurfactant production by optimal factor combinations like Waste glycerol (1%v/v), peptone (1%w/v), NaCl 0.4% (w/v), and pH 6. Under optimal conditions, the purified biosurfactant reduced the surface tension to 35 mN/m from 72.8 mN/m (MSM) and a critical micelle concentration of 25 mg/ml was achieved. Spectroscopic analyses of the purified biosurfactant using Nuclear Magnetic Resonance suggested it as a lipopeptide biosurfactant. The evaluation of mechanistic antibacterial, antiradical, antiproliferative, and cellular effects indicated the efficient antibacterial activity (against Pseudomonas aeruginosa) of biosurfactants due to free radical scavenging activity and oxidative stress. Moreover, the cellular cytotoxicity was estimated by MTT and other cellular assays revealing the phenomenon as the dose-dependent induction of apoptosis due to free radical scavenging with an LC50 of 55.6 ± 2.3 mg/ml.

Description of Dissolved Organic Matter Transformational Networks at the Molecular Level.

Dissolved Organic Matter (DOM) is an important component of the global carbon cycle. Unscrambling the structural footprint of DOM is key to understand its biogeochemical transformations at the mechanistic level. Although numerous studies have improved our knowledge of DOM chemical makeup, its three-dimensional picture remains largely unrevealed. In this work, we compare four solid phase extracted (SPE) DOM samples from three different freshwater ecosystems using high resolution mobility and ultrahigh-resolution Fourier transform ion cyclotron resonance tandem mass spectrometry (FT-ICR MS/MS). Structural families were identified based on neutral losses at the level of nominal mass using continuous accumulation of selected ions-collision induced dissociation (CASI-CID)FT-ICR MS/MS. Comparison of the structural families indicated dissimilarities in the structural footprint of this sample set. The structural family representation using Cytoscape software revealed characteristic clustering patterns among the DOM samples, thus confirming clear differences at the structural level (Only 10% is common across the four samples.). The analysis at the level of neutral loss-based functionalities suggests that hydration and carboxylation are ubiquitous transformational processes across the three ecosystems. In contrast, transformation mechanisms involving methoxy moieties may be constrained in estuarine systems due to extensive upstream lignin biodegradation. The inclusion of the isomeric content (mobility measurements at the level of chemical formula) in the structural family description suggests that additional transformation pathways and/or source variations are possible and account for the dissimilarities observed. While the structural character of more and diverse types of DOM samples needs to be assessed and added to this database, the results presented here demonstrate that Graph-DOM is a powerful tool capable of providing novel information on the DOM chemical footprint, based on structural interconnections of precursor molecules generated by fragmentation pathways and collisional cross sections.

Chemistry and biology of ent-morphinan alkaloids.

Morphinan alkaloids have attracted constant attention since the isolation of morphine by Sertürner in 1805. However, a group of 45 compounds possessing a complete ent-morphinan backbone can also be found in the literature. These compounds are related to the morphinandienone subgroup and display a substitution pattern which is different from the morphinans. In particular, these alkaloids could be substituted at position C-2 and C-8 either by a hydroxy function or a methoxy moiety. Four groups of ent-morphinan alkaloids can be proposed, the salutaridine, pallidine, cephasugine and erromangine series. Interestingly, the botanical distribution of the ent-morphinans is more widespread than for the morphinans and includes the Annonaceae, Berberidaceae, Euphorbiaceae, Fumariaceae, Hernandiaceae, Lauraceae, Menispermaceae, Monimiaceae, Papaveraceae, and Ranunculaceae families. To date, their exact mode of production remains elusive and their interplay with the biosynthetic pathway of other classes of benzyltetrahydroisoquinoline alkaloids, in particular aporphines, should be confirmed. Exploration of the biological and therapeutic potential of these compounds is limited to some areas, namely central nervous system (CNS), inflammation, cancer, malaria and viruses. Further studies should be conducted to identify the cellular/molecular targets in view of promoting these compounds as new scaffolds in medicinal chemistry.

Quantitative and qualitative analyses of drug adsorption on silver nanoparticle monolayers: QCM, SERS, and TEIRA nanospectroscopy studies.

In this study for the first time, surface-enhanced Raman spectroscopy (SERS) and tip-enhanced infrared (TEIRA) nanospectrocopy together with a quartz crystal microbalance (QCM) are postulated as powerful tools for comprehensive qualitative and quantitative analyses of drug/metal nanocarrier conjugates. The development of efficient drug/carrier systems requires that the stability of the drug/carrier connection be estimated and the number of drug molecules immobilized on the carrier surface be determined. Thus, such a characterization study is highly desirable. Here, the SERS technique was applied to identify how erlotinib, a drug applied in non-small cell lung cancer (NSCLC) therapy, interacts with silver nanoparticles (AgNPs) that are considered as drug carriers. These investigations indicate that in the erlotinib/AgNP suspension, the drug strongly connects with the NPs mainly through the phenylacetylene moiety. The QCM was used to prepare an AgNP monolayer with a monitored degree of coverage and to perform controlled erlotinib adsorption as a next step. The results indicate that the drug forms a stable layer on the AgNP monolayer and also show the amount of the erlotinib molecules which underwent immobilization on the metal nanosurface. Simultaneously, it was identified how the erlotinib layer adsorbs on the AgNP monolayer using TEIRA nanospectroscopy with ultra-high spatial resolution. The obtained results show that the phenylacetylene, ethoxy, and methoxy moieties are mainly responsible for the drug/AgNP monolayer connection. Additionally, the performed studies also try to explain the surface-enhanced phenomena that occur during the TEIRA experiments and attempt to prove the statement that the "tip-enhanced" effect plays a crucial role in the detection of the thin erlotinib layer deposited on the AgNP monolayer.