Nuclear Overhauser Effect Research Articles

Streptospherin A, a New Cancer Stem Cell Inhibitor, Produced by Streptomyces sp. KUSC-240.

Cancer stem cells (CSCs) are a major cause of tumor recurrence; therefore, using CSC inhibitors is a potential strategy for cancer chemotherapy. We used our previously reported screening system that targets CSCs to identify a new scarce compound, streptospherin A (1), isolated from Streptomyces sp. KUSC-240. The planar structure of 1 was determined by high-resolution-MS (HR-MS) and NMR analysis. Nuclear Overhauser effect spectroscopy correlation and J-resolved heteronuclear multiple bond connectivity analysis revealed the partial relative configuration on the tetrahydropyran ring. Streptospherin A (1) inhibited CSC sphere formation and suppressed the growth of CSCs. These results suggest that streptospherin A (1) is a potential anticancer agent that may target CSCs.

Abstract 3156: A surface plasmon resonance-based screening platform to identify potential PD-1/PD-L1 inhibitors from a FDA-approved drugs library for cancer immunotherapy

Abstract The PD-1/PD-L1 axis plays a pivotal role in immune checkpoint regulation in cancer, making its inhibition a key strategy in cancer immunotherapy. However, the development of small molecule inhibitors targeting PD-1/PD-L1 interaction has been hindered by the lack of robust high-throughput screening platforms. In this study, we developed a high-throughput screening platform based on surface plasmon resonance (SPR) technology, utilizing a 384-well plate format. This platform integrates a dual-step coupling method, employing both amine and bio-streptavidin coupling to optimize PD-1 orientation on the sensor chip.We screened a library of 2, 764 FDA-approved drugs using this SPR platform with a 1:1 ratio of drug to PD-L1, alongside two positive control PD-L1 inhibitors. Three compounds, RB, MB, and VP, were identified as hits, showing PD-1/PD-L1 blockade rates of 13.1%, 9.6%, and 6.7%, respectively, compared to the positive controls BMS-1166 (33%) and BMS-202 (8.4%). Structural validation through saturation transfer difference nuclear magnetic resonance (STD-NMR) spectroscopy confirmed the binding of RB to PD-L1, with a unique STD peak at 7.6 ppm, further supported by a WaterLOGSY control experiment indicating a negative nuclear overhauser effect to water. The dissociation constants KD of RB were determined using SPR, revealing moderate binding affinities to PD-L1.Cytotoxicity assays conducted on Jurkat T cells and A375 melanoma cells demonstrated that RB exhibited no toxicity across a concentration range from 100 μM to 0.01 μM. Functional assays using a co-culture model of T cells and cancer cells, designed to replicate the tumor microenvironment, showed that RB treatment modulated IL-2 secretion and induced apoptosis in A375 cancer cells. Proteomic analysis of sorted Jurkat T cells from the co-culture model via bottom-up proteomics revealed key proteins and signaling pathways regulated by RB.Overall, these findings suggest that RB exerts significant PD-1/PD-L1 inhibitory activity and may hold promise as a repurposed drug candidate for cancer immunotherapy. Citation Format: Huifang Li, Ang Cai, Navindra P. Seeram, Chang Liu. A surface plasmon resonance-based screening platform to identify potential PD-1/PD-L1 inhibitors from a FDA-approved drugs library for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3156.

Influence of Glucose on the Self-Assembly and Photophysical Properties of Hydrophilic Pluronic F98.

This study investigates the effect of glucose, a kosmotropic osmolyte, on the micellization and hydration dynamics of the highly hydrophilic triblock copolymer (BCP), Pluronic F98. The outcomes obtained from the physicochemical studies are described. Clouding behavior demonstrated that increasing glucose concentration decreases the CP, highlighting a sugaring-out effect. Surface tension (γ) measurements revealed that glucose enhances hydrophobic interactions at the air-liquid interface, promoting micellization. The relative viscosity (ηrel) increases, suggesting the dehydration of the poly(ethylene oxide) (PEO) blocks of F98. The sugaring-out effect of the PEO and PPO blocks of F98 in the presence of glucose was evaluated by monitoring changes in bond stretching using Fourier-transform infrared (FT-IR) spectroscopy, which was further corroborated through two-dimensional Nuclear Overhauser Effect Spectroscopy (2D-NOESY) analysis that inferred glucose to remain in the PEO hydrated shell. These spectroscopic findings were further validated through the evaluation of optimum descriptors using computational simulations performed with the DFT/B3LYP method within the 3-21G basis set framework, utilizing the Gaussian 5.0.9 software. Fluorescence spectroscopy, using pyrene as a probe, confirmed a glucose-induced decrease in the I1/I3 ratio, suggesting increased hydrophobicity and a lower critical micelle temperature (CMT). Photophysical studies employing fluorescein sodium salt (FLU) dye demonstrated that glucose concentration and temperature modulate the microenvironment that has not been explored in prior studies, emphasizing the novelty and originality of this work, leading to a blue shift at lower glucose concentrations and a red shift at 1.0 M glucose as a function of temperature. Despite spectral shifts, the fluorescence lifetime (∼3.5 ns) remains unchanged. Fluorescence quenching of FLU-loaded F98 micelles with potassium iodide (KI) confirmed dynamic quenching at the micelle-water interface. Dynamic light scattering (DLS) inferred a temperature-dependent variation in micelle size attributed to hydrogen bonding and hydrophilic interactions, while small-angle neutron scattering (SANS) analysis, using a core-shell spherical model, detailed the micellar structural changes.

NMR2-Based Drug Discovery Pipeline Presented on the Oncogenic Protein KRAS.

Fragment-based drug discovery has emerged as a powerful approach for developing therapeutics against challenging targets, including the GTPase KRAS. Here, we report an NMR-based screening campaign employing state-of-the-art techniques to evaluate a library of 890 fragments against the oncogenic KRAS G12V mutant bound to GMP-PNP. Further HSQC titration experiments identified hits with low millimolar affinities binding within the SI/SII switch region, which forms the binding interface for the effector proteins. To elucidate the binding modes, we applied NMR molecular replacement (NMR2) structure calculations, bypassing the need for a conventional protein resonance assignment. Traditionally, NMR2 relies on isotope-filtered nuclear Overhauser effect spectroscopy experiments requiring double-labeled [13C,15N]-protein. We introduce a cost-efficient alternative using a relaxation-based filter that eliminates isotope labeling while preserving structural accuracy. Validation against standard isotopically labeled workflows confirmed the equivalence of the derived protein-ligand structures. This approach enabled the determination of 12 NMR2 KRAS-fragment complex structures, providing critical insights into structure-activity relationships to guide ligand optimization. These results demonstrate the streamlined integration of NMR2 into a fragment-based drug discovery pipeline composed of screening, binding characterization, and rapid structural elucidation with or without isotopic labeling.

In Vivo Brain B1 + Inhomogeneity Correction and NOE Image Enhancement at 7 T via Flexible Metasurfaces.

Nuclear Overhauser effect (NOE) MRI has been used for invivo brain imaging to assess lipid and protein composition and benefits from 7 T field strengths due to the larger chemical shift dispersion. However, a continuing challenge is signal drop off observed in regions such as the medial temporal lobes due to "standing wave" effects from shorter radiofrequency (RF) wavelengths at ultra-high fields. 2D periodic unit cell metasurfaces have been a promising approach for providing improvements in anatomical imaging but have not yet been evaluated in chemical exchange saturation transfer (CEST)-based sequences. Here, we report the use of metasurfaces for enhancement of NOE imaging as well as for improvement of Lorentzian line fitting of full Z-spectrum data. 3D NOE image data, B1 + maps, and B0 maps were acquired on five healthy volunteers using a 7 T MRI system with and without metasurfaces positioned near the temporal lobes. A frequency offset range of -5 to +5 ppm with additional separate acquisitions of ±20 and ±100 ppm offset images. A five-pool Lorentzian line fitting model was employed to fit and quantitatively compared magnetization transfer (MT), amide proton transfer (APT), amine, and relayed NOE (rNOE) metabolite pools. NOEMTR-weighted contrast maps were also calculated via Z-spectrum asymmetry analysis. The metasurfaces globally enhanced the transmit efficiency within the imaging slab by approximately 9.6% and reduced B1 + inhomogeneity by approximately 16.6% and increased transmit efficiency by 55.8% in the temporal lobes. Amplitude fit maps showed decreases in contrast magnitude ranging from 1 to 16% and changes in image uniformity ranging from a 4.3 decrease to a 34.7% increase, while NOEMTR-weighted contrast maps demonstrated similar changes. The results presented here demonstrate that metasurfaces can enhance CEST-based techniques complementing previously reported benefits in anatomical imaging.

Stereocontrolled synthesis and nuclear magnetic resonance analysis of boranophosphate/phosphate chimeric oligonucleotides.

This report describes the stereoselective synthesis of boranophosphate/phosphate (PB/PO) chimeric oligodeoxynucleotides (ODNs) and the nuclear magnetic resonance (NMR) analysis of oligomers containing PB linkages. This stereoselective synthesis involved dimer building blocks containing highly stereopure boranophosphotriester linkages, which enabled the synthesis of PB/PO chimeric ODNs via the standard phosphoramidite method. The stereochemistry of dinucleoside and trinucleoside PBs was confirmed by nuclear Overhauser effect spectroscopy (NOESY) experiments. In the NOESY experiments, the stereochemistry was determined from the correlation of the protons of the borane (BH3) group with those of neighbouring 2'-deoxyribose moieties or nucleobases. Thus, the stereochemistry of the PB linkages within the oligomer was determined, and the stereopurity was also confirmed. A PB linkage was introduced into ODNs with retention of the P-configuration of the dimer building blocks without any loss of stereopurity during solid-phase synthesis. This synthetic approach is expected to be a reliable method for introducing PB linkages with precise stereochemistry. Additionally, detailed analysis of the PB linkages via NMR allowed accurate determination of the stereochemistry.

Relaxation Optimized Heteronuclear Experiments for Extending the Size Limit of RNA Nuclear Magnetic Resonance.

The application of NMR to large RNAs has been limited by the inability to perform heteronuclear correlation experiments essential for resolving overlapping 1H NMR signals, determining interproton distance restraints and interhelical orientations for structure calculations, and evaluating conformational dynamics. Approaches exploiting 1H-13C correlations that are routinely applied to proteins and small RNAs of ∼60 nucleotides or fewer are impractical for larger RNAs due to rapid dipolar relaxation of protons by their attached carbons. Here we report a 2H-enhanced, 1H-15N correlation approach that enables atom-specific NMR characterization of much larger RNAs. Purine H8 transverse relaxation rates are reduced ∼20-fold with ribose perdeuteration, enabling efficient magnetization transfer via two-bond 1H-15N couplings. We focus on H8-N9 correlation spectra which benefit from favorable N9 chemical shift anisotropy. Chemical shift assignment is enabled by retention of protons at the C1' position, which allow measurement of two-bond H1'-N9 and through-space H1'-H8 correlations with only a minor effect on H8 relaxation. The approach is demonstrated for the 232 nucleotide HIV-1 Rev response element, where chemical shift assignments, 15N-edited nuclear Overhauser effects, and 1H-15N residual dipolar couplings are readily obtained from sensitive, high-resolution spectra. Heteronuclear correlated NMR methods that have been essential for the study of proteins can now be extended to RNAs of at least 78 kDa.

Endowing Polycyclic Aromatic Hydrocarbons with Induced Supramolecular Chirality by Engineering Cation-π Interaction.

The cation-π interaction is a crucial noncovalent binding force prevalent in many biological and chemical systems, however, are rarely reported in chiral supramolecular systems. Here, a supramolecular chiral system is reported, wherein cation-π interaction play significant roles. The interaction involves a chiral cationic palladium complex (R-Pd) co-assembling with 12 different polycyclic aromatic hydrocarbons (PAHs), resulting in the formation of supramolecular gels in mixed solvents. This co-assembly induces supramolecular chirality in the PAHs, with cation-π interaction identified as the primary driving force. The confirmation of this interaction is supported by high-resolution mass, 1H NMR, nuclear overhauser effect spectroscopy (NOESY), XRD and CD. Most importantly, with the synergy of hydrogen bonds, the cation-π interaction can be stabilized in a mixed solvent containing water, leading the co-assembly to form supramolecular gel, as well as enhanced chiral induction of PAHs. This discovery serves as a proof-of-principle example showing how the weak cation-π interaction could be a powerful guide in attaining induced chirality of PAHs.

Protocol for converting assigned nuclear Overhauser enhancement spectroscopy series peaks into exact distance restraints using MATLAB- or CYANA-eNORA.

Protocol for converting assigned nuclear Overhauser enhancement spectroscopy series peaks into exact distance restraints using MATLAB- or CYANA-eNORA.

Application of deep eutectic solvents for the simultaneous determination of organophosphorus and pyrethroid pesticides in aqueous matrices and the assessment of its level of whiteness.

Application of deep eutectic solvents for the simultaneous determination of organophosphorus and pyrethroid pesticides in aqueous matrices and the assessment of its level of whiteness.

Molecules in the Serotonin-Melatonin Synthesis Pathway Have Distinct Interactions with Lipid Membranes.

The neurotransmitter serotonin is involved in physiological processes such as appetite, sleep, and mood and diseases such as anxiety and depression. Traditionally, the effects of serotonin were thought to be initiated by binding to its target transmembrane receptors. It is also known that serotonin can bind directly to the membrane with high affinity and modulate lipid dynamics, lateral segregation of lipids, vesicular association, and membrane protein activity. We investigated if other small molecules in the serotonin metabolic pathway, some of which are known to be signaling molecules while some others are not, have similar membrane modulating effects. Therefore, we examined serotonin and several of its metabolites: 5-hydroxytryptophan (5-HTP), serotonin, N-acetylserotonin (NAS), and melatonin in model membranes mimicking synaptic membranes. Using 2H NMR spectroscopy of deuterated 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC), we observed that all metabolites disorder the synaptic membrane-mimicking model membranes. The largest disordering effect was observed for NAS and the smallest for tryptophan. Using fluorescence correlation spectroscopy, it was found that only NAS promotes vesicular association similar to that of serotonin, while the others did not. Furthermore, we found that the serotonin metabolites differed in their membrane distribution by employing solid state 1H magic angle spinning nuclear Overhauser enhancement spectroscopy (NOESY) experiments in simple POPC membranes. Similar results were obtained in synaptic membrane mimics using molecular dynamics simulations. In conclusion, while the causal correlation between membrane modulation effects and membrane distribution for the serotonin metabolites remains elusive, this study suggests that small-molecule metabolites and drugs can have drastic biological effects mediated through the membrane. The finding that small changes in structure lead to very different membrane modulation and distributions suggests the possibility of developing membrane modulating drugs in the future.

Electrolyte Solvent‐Ion Configuration Deciphering Lithium Plating/Stripping Chemistry for High‐Performance Lithium Metal Battery

AbstractElectrolyte engineering plays a critical role in tuning lithium plating/stripping behaviors, thereby enabling safer operation of lithium metal anodes in lithium metal batteries (LMBs). However, understanding how electrolyte microstructures influence the lithium plating/stripping process at the molecular level remains a significant challenge. Herein, using a commonly employed ether‐based electrolyte as a model, the role of each electrolyte component is elucidated and a relationship between electrolyte behavior and the lithium plating/stripping process is established by investigating the effects of electrolyte compositions, including solvents, salts, and additives. The variations in Li+ deposition kinetics are not only analyzed by characterizing the lithium deposition overpotential and exchange current density but it is also identified that the intermolecular interactions are the previously unexplored cause of these variations by 2D nuclear overhauser effect spectroscopy (NOESY). An interfacial model is developed to explain how solvent interactions, distinct roles of anions, and critical effects of additives influence Li+ desolvation kinetics and the thermodynamic stability of desolvation clusters during lithium plating/stripping process. This model clarifies how these configurations of solvents and ions are related to the macroscopic properties of lithium plating/stripping chemistry. These findings contribute to more uniform and controllable lithium deposition, providing valuable insights for designing advanced electrolyte systems for LMBs.

Chermesins I-N: Bioactive spiromeroterpenoids from the marine-sourced fungus Penicillium chermesinum AS-400.

Chermesins I-N: Bioactive spiromeroterpenoids from the marine-sourced fungus Penicillium chermesinum AS-400.

In vivo imaging of glycogen in human muscle

Probing regional glycogen metabolism in humans non-invasively has been challenging due to a lack of sensitive approaches. Here we studied human muscle glycogen dynamics post-exercise with a spatial resolution of millimeters and temporal resolution of minutes, using relayed nuclear Overhauser effect (glycoNOE) MRI. Data at 5T showed a homogeneous distribution of glycogen in resting muscle, with an average concentration of 99 ± 13 mM. After plantar flexion exercise following fasting with recovery under fasting conditions, the calf muscle showed spatially heterogeneous glycogen depletion and repletion kinetics that correlated with the severity of this depletion. Three types of regional glycogen kinetics were observed: (i) single exponential repletion (type a); (ii) biphasic recovery of rapid repletion followed by additional depletion (type b); (iii) biphasic recovery where continued depletion is followed by an exponential recovery (type c). The study of the complex patterns of glycogen kinetics suggests that glycogen breakdown may be quantitatively important during the initial recovery.

Diffuse nuclear Overhauser effect MRI contrast changes detected in multiple sclerosis subjects at 7T.

Multiple sclerosis is an inflammatory demyelinating condition of the central nervous system affecting approximately 1 million people in the USA. Although standard structural MRI techniques are now the main imaging modality for multiple sclerosis diagnosis and management, they are yet to provide information regarding the metabolic profile of the disease. Ultra-high field 7T MRI systems have provided gains in signal-to-noise ratio (SNR) and spatial resolution for structural MRI as well as larger chemical shifts leading to improvements in specialized imaging sequences, such as nuclear Overhauser effect (NOE) imaging, that can evaluate macromolecular metabolite composition. In this work, NOE images were acquired on a cohort of multiple sclerosis and healthy control subjects to spatially map differences in their lipid metabolites as a result of NOE effects. NOE image data were acquired on a total of 25 subjects {15 multiple sclerosis subjects [10 females, 5 males (21-70 years)] and 10 healthy controls [5 females, 5 males (23-71 years)]} on a 7T MRI system with a frequency offset range of -5 to 5 ppm. A five-pool Lorentzian line fitting model was utilized to fit and quantitatively compare direct saturation (DS), magnetization transfer (MT), amide proton transfer (APT), amine, and relayed NOE (rNOE) and used as a comparison to conventional T1 maps. Grey and white matter tissues were segmented using the T1 maps, while the lesion tissue was segmented manually. Correlations between disease duration and lesion load were performed to investigate any existing relationship to image contrast. The primary findings of this work include statistically significant decreases in the rNOE pool for the normal-appearing white matter (NAWM) (11.4% decrease) and normal-appearing grey matter (NAGM) (10.6% decrease) in multiple sclerosis subjects compared to healthy controls. Additionally, a significant decrease in the amine pool was also observed for NAWM (15.3% decrease) in multiple sclerosis subjects compared to healthy controls. Changes in multiple sclerosis lesion contrast were also observed for several pools (DS, amine, and rNOE). Decreases in both the rNOE and amine pools suggest that in multiple sclerosis, there are diffuse decreases in mobile lipids, such as those found in neuronal cell bodies, as well as a decrease in proteins with amine groups. Furthermore, these measurable contrast changes were not detected in the corresponding T1 maps. NOE imaging can provide complementary metabolic information to conventional MRI methods. Future studies will focus on utilizing this technique for longitudinal tracking of disease progression and investigating similar demyelinating diseases.

REGIOISOMERIC N-ALKYLATION OF SOME INDAZOLES

Objective: Indazole scaffold have two interconvertible tautomeric forms. Based on our previous studies, regioisomeric N-alkylation of some indazole analogs was synthesized in this study and their structures were elucidated by 2D NMR methods. Material and Method: Regioisomers were resolved for N-benzylations and alkylation of some non-substituted and substituted indazoles, under basic conditions (K2CO3) in DMF. Result and Discussion: It was observed that, their occurrence ratios of N1 : N2 is almost equal (50%). Their structures were established by combination of 1H-1H NOE (Nuclear Overhauser Effect Spectroscopy, NOESY) and HMBC (Heteronuclear Multiple Bond Correlation) NMR methods.

Altered amino and fatty acids metabolism in Sudanese prostate cancer patients: insights from metabolic analysis.

Prostate cancer (PCa) management presents a multifaceted clinical challenge, intricately linking oncological considerations with cardiovascular health. Despite the recognized importance of lipid metabolism and hypertension in this interwoven relationship, their involvement in PCa development remains partially understood. This study aimed to explore variations in plasma metabolome among Sudanese PCa patients and their associated comorbidities. Plasma samples were collected from 50 patients across four hospitals in Sudan and profiled by nuclear magnetic resonance (NMR) spectroscopy. One-dimensional proton NMR spectra were acquired for each sample using standard nuclear Overhauser effect spectroscopy pulse sequence presat on a 500 MHz Bruker Avance III HD NMR spectrometer. Metabolite concentrations were quantified using R scripts developed in-house. Univariate and multivariate analyses were generated in the R software. Patients were categorized into four distinct metabotypes based on their metabolic profiles, and statistical analyses were conducted to evaluate the significance of observed differences. Our findings revealed high levels of fatty acids, phospholipids, cholesterol, valine, leucine, and isoleucine associated with non-hypertensive patients. In contrast, hypertensive patients were associated with high GlycA and GlycB levels and altered amino acid metabolism. These findings underscore the intricate interplay between metabolic dysregulation and hypertension in PCa patients. Further research is warranted to elucidate the precise molecular pathways underlying lipid metabolism in PCa and to explore the therapeutic potential of targeting these pathways. In conclusion, our study contributes to a deeper understanding of the metabolic landscape of PCa in Sudanese patients, emphasizing the importance of personalized approaches in cancer management.

Nonlinear parameter estimation with physics-constrained spectral–spatial priors for highly accelerated chemical exchange saturation transfer MRI

Objective.To develop a nonlinear, model-based parameter estimation method directly from incomplete measurements ink - wspace for robust spectral analysis in highly accelerated chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI).Approach. A CEST-specific, separable nonlinear model, which describes spectral decomposition using multi-pool Lorentzian functions (conventional magnetization transfer (MT), direct saturation of water signals (DS), amide, amine, and nuclear Overhauser effect) derived from the steady-state Bloch McConnel equation, is incorporated into a measurement model in CEST MRI. Furthermore, signal drop in saturation transfer experiments is formulated by an additional, separable nonlinear spectral prior indicating that the symmetric z-spectra synthesized using conventional MT and DS always remain higher or equal to the whole z-spectra with all pools. Given the above considerations, linear and nonlinear parameters in the proposed method are estimated in an alternating fashion directly from highly incomplete measurements ink - wspace by solving a constrained optimization problem with the physics-constrained spectral priors while imposing additional sparsity priors on spatial parameter maps.Main results.Compared with conventional methods, the proposed method yields clearer delineation of tumor-specific CEST maps without apparent artifact and noise.Significance.We successfully demonstrated the feasibility of the proposed method for CEST MRI with highly incomplete measurements thus enabling high-resolution whole brain CEST MRI in clinically reasonable imaging time.

Comparative Analysis of Bare and Quercetin-Loaded Nonionic Block Copolymer Micelles in an Artificial Gastrointestinal Medium.

Block copolymer micelles have been increasingly used for the solubilization and delivery of hydrophobic drugs. There exists a possibility of dissociation of micelles and formation of other association structures in contact with the gastrointestinal fluid. In this study, we demonstrated the effect of the fed-state intestinal fluid (FeSSIF) upon characteristics of bare and quercetin (QCT)-loaded pluronic 123 (P123) micelles. Characterizations were performed using dynamic light scattering (DLS), 1H NMR, heteronuclear single-quantum coherence (HSQC), two-dimensional 1H-1H nuclear Overhauser effect spectroscopy (2D-NOESY), and diffusion-ordered spectroscopy (DOSY). In the case of bare micelles, we found copolymer-bile salt mixed aggregates without any noticeable change in size. DOSY data revealed that lecithin formed a separate aggregate in the FeSSIF. Complete micellar solubilization of QCT could be verified by the disappearance of its proton signals. At higher dose levels, the diffusion coefficient of micelles increased in the FeSSIF. We speculate that QCT-induced hydrophobicity and availability of FeSSIF components would have driven the formation of small-sized mixed assemblies. On the contrary, the diffusion coefficient of micelles decreased with an increase in the QCT load in the medium devoid of FeSSIF components. We deduce that lack of lecithin and bile salts precluded the formation of mixed assemblies in this case, and therefore, micelles turned heavier at higher QCT loads. Such insights on self-assembled formulations can be valuable in improving their biological performance.

Structural characterization and physicochemical properties of different hydrophilic natural deep eutectic solvents.

To overcome the toxic nature of organic solvents, scientific interest in the use of green solvents, particularly natural deep eutectic solvents (NADES), has increased over the past decade, leading to new applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Understanding the physicochemical properties and molecular interactions of NADES is essential for uncovering new potential applications in these fields. In this study, several lactic and citric acid-based NADES, as well as chloride choline- and urea-based NADES, were evaluated for their physicochemical properties, including density, pH, viscosity, conductivity, and refractive index. Additionally, nuclear magnetic resonance (NMR), and in particular nuclear Overhauser enhancement spectroscopy (NOESY), was employed to investigate the intermolecular interactions between the NADES components to confirm the formation of the eutectic mixture. The extraction efficiency of the confirmed NADES was tested for extracting polyphenols as a proof of concept to highlight their relationship with the measured properties. Lactic and choline chloride-based NADES provided the highest extraction yields. These results were also compared with the predicted extraction capabilities of each NADES provided by the COSMO-RS software.