DFT Calculations of H and C NMR Chemical Shifts of Hydroxy Secondary Oxidation Products of Geometric Isomers of Conjugated Linoleic Acid Methyl Esters: Structures in Solution and Revision of NMR Assignments.

Detailed DFT studies of H and C NMR chemical shifts of hydroxy secondary oxidation products of various geometric isomers of conjugated linolenic acids methyl esters are presented. Several low energy conformers were identified for model compounds of the central dienenol OH moiety, which were found to be practically independent on the various functionals and basis sets used. This greatly facilitated the minimization process of the geometric isomers of conjugated linolenic acids methyl esters.

Phytochemical Analysis and Biological Evaluation of Carob Leaf ( L.) Crude Extracts Using NMR and Mass Spectroscopic Techniques.

Carob leaves have gained attention for their bioactive properties and traditional medicinal uses, including as treatment for diabetes, digestive disorders, and microbial infections. The aim of this study was to explore the phytochemical composition of carob leaf acetone extracts using advanced spectroscopic techniques. The combined use of heteronuclear nuclear magnetic resonance (NMR) experiments with 1D selective nuclear Overhauser effect spectroscopy (NOESY) offers detailed structural insights and enables the direct identification and quantification of key bioactive constituents in carob leaf extract.

S NMR: Recent Advances and Applications.

The purpose of this review is to present advances and applications of S NMR, which is an underutilized NMR spectroscopy. Experimental NMR aspects in solution, chemical shift tendencies, and quadrupolar relaxation parameters will be briefly summarized. Emphasis will be given to advances and applications in the emerging fields of solid-state and DFT computations of S NMR parameters.

NMR and Docking Calculations Reveal Novel Atomistic Selectivity of a Synthetic High-Affinity Free Fatty Acid vs. Free Fatty Acids in Sudlow's Drug Binding Sites in Human Serum Albumin.

Saturation transfer difference (STD), inter-ligand NOEs (INPHARMA NMR), and docking calculations are reported for investigating specific binding sites of the high-affinity synthetic 7-nitrobenz-2-oxa-1,3-diazoyl-4-C fatty acid (NBD-C FA) with non-labeled human serum albumin (HSA) and in competition with the drugs warfarin and ibuprofen. A limited number of negative interligand NOEs between NBD-C FA and warfarin were interpreted in terms of a short-range allosteric competitive binding in the wide Sudlow's binding site II (FA7) of NBD-C FA with Ser-202, Lys-199, and Trp-214 and warfarin with Arg-218 and Arg-222. In contrast, the significant number of interligand NOEs between NBD-C FA and ibuprofen were interpreted in terms of a competitive binding mode in Sudlow's binding site I (FA3 and FA4) with Ser-342, Arg-348, Arg-485, Arg-410, and Tyr-411.

Ultrasound-Assisted Extraction of Taro Leaf Antioxidants Using Natural Deep Eutectic Solvents: An Eco-Friendly Strategy for the Valorization of Crop Residues.

L. leaves are considered a by-product of taro cultivation and are discarded as environmental waste, despite their valuable phenolic composition. Their valorization to obtain value-added substances for medicinal, food, and cosmetic applications is the aim of the current work.

Structural Studies of Monounsaturated and ω-3 Polyunsaturated Free Fatty Acids in Solution with the Combined Use οf NMR and DFT Calculations-Comparison with the Liquid State.

Molecular structures, in chloroform and DMSO solution, of the free fatty acids (FFAs) caproleic acid, oleic acid, α-linolenic acid, eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) are reported with the combined use of NMR and DFT calculations. Variable temperature and concentration chemical shifts of the COOH protons, transient 1D NOE experiments and DFT calculations demonstrate the major contribution of low molecular weight aggregates of dimerized fatty acids through intermolecular hydrogen bond interactions of the carboxylic groups, with parallel and antiparallel interdigitated structures even at the low concentration of 20 mM in CDCl. For the dimeric DHA, a structural model of an intermolecular hydrogen bond through carboxylic groups and an intermolecular hydrogen bond between the carboxylic group of one molecule and the ω-3 double bond of a second molecule is shown to play a role.

Molecular Basis for the Selectivity of DHA and EPA in Sudlow's Drug Binding Sites in Human Serum Albumin with the Combined Use of NMR and Docking Calculations.

Medium- and long-chain saturated and unsaturated free fatty acids (FFAs) are known to bind to human serum albumin (HSA), the main plasma carrier protein. Atomic-level structural data regarding the binding mode in Sudlow's sites I (FA7) and II (FA4, FA3) of the polyunsaturated ω-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), however, are largely unknown. Herein, we report the combined use of saturation transfer difference (STD) and Interligand NOEs for Pharmacophore Mapping (INPHARMA) NMR techniques and molecular docking calculations to investigate the binding mode of DHA and EPA in Sudlow's sites Ι and ΙΙ of HSA.

ANTIAGE-DB: A Database and Server for the Prediction of Anti-Aging Compounds Targeting Elastase, Hyaluronidase, and Tyrosinase.

Natural products bear a multivariate biochemical profile with antioxidant, anti-inflammatory, antibacterial, and antitumoral properties. Along with their natural sources, they have been widely used both as anti-aging and anti-melanogenic agents due to their effective contribution in the elimination of reactive oxygen species (ROS) caused by oxidative stress. Their anti-aging activity is mainly related to their capacity of inhibiting enzymes like Human Neutrophil Elastase (HNE), Hyaluronidase (Hyal) and Tyrosinase (Tyr).

Structural Basis of Artemisinin Binding Sites in Serum Albumin with the Combined Use of NMR and Docking Calculations.

Artemisinin is known to bind to the main plasma protein carrier serum albumin (SA); however, there are no atomic level structural data regarding its binding mode with serum albumin. Herein, we employed a combined strategy of saturation transfer difference (STD), transfer nuclear Overhauser effect spectroscopy (TR-NOESY), STD-total correlation spectroscopy (STD-TOCSY), and Interligand Noes for PHArmacophore Mapping (INPHARMA) NMR methods and molecular docking calculations to investigate the structural basis of the interaction of artemisinin with human and bovine serum albumin (HSA/BSA). A significant number of inter-ligand NOEs between artemisinin and the drugs warfarin and ibuprofen as well as docking calculations were interpreted in terms of competitive binding modes of artemisinin in the warfarin (FA7) and ibuprofen (FA4) binding sites.

Density functional theory calculations of δ( C) and δ( H) chemical shifts and J( COO H) coupling constants as structural and analytical tools in hydroperoxides: Prospects and limitations of H C heteronuclear multiple bond correlation experiments.

Density functional theory (DFT) calculations of δ( C) and δ( H) chemical shifts and J( COO H) coupling constants of three model hydroperoxides of the naturally occurring cis-11-OOH and trans-9-OOH isomers of oleate and 9-cis, 11-trans-16-OOH endo hydroperoxide of methyl linolenate are reported. The computational δ(OOH) for various functionals and basis sets were found to be nearly identical for the cis/trans geometric isomers. The chemical shifts of the methine CHOOH protons and carbons, on the contrary, are highly diagnostic for the identification of cis/trans geometric isomerism.

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives.

Mono- and polyunsaturated lipids are particularly susceptible to peroxidation, which results in the formation of lipid hydroperoxides (LOOHs) as primary nonradical-reaction products. LOOHs may undergo degradation to various products that have been implicated in vital biological reactions, and thus in the pathogenesis of various diseases. The structure elucidation and qualitative and quantitative analysis of lipid hydroperoxides are therefore of great importance.

NMR and computational studies reveal novel aspects in molecular recognition of unsaturated fatty acids with non-labelled serum albumin.

An approach based on the combined use of saturation transfer difference (STD), Tr-NOESY and Inter-ligand NOEs for PHArmacophore Mapping (INPHARMA) NMR techniques and docking calculations is reported, for the first time, for mapping interactions and specific binding sites of caproleic acid (10 : 1 cis-9), oleic acid (18 : 1 cis-9), linoleic acid (18 : 2 cis-9,12) and linolenic (18 : 3, cis-9,12,15) free fatty acids (FFAs) with non-labelled serum albumin (BSA/HSA). Significant negative inter-ligand NOEs between the FFAs and the drugs ibuprofen and warfarin, through competition experiments, were observed. The inter-ligand NOEs and docking calculations were interpreted in terms of competitive binding mode, the significant folding of the bis allylic region and the presence of two orientations of the FFAs in the warfarin binding site (FA7), due to two potential distinctive anchoring polar groups of amino acids.

Serum albumin as a primary non-covalent binding protein for nitro-oleic acid.

This work explores the interaction of 9/10-nitro-oleic acid (NO-OA) with human serum albumin (HSA). The molecular mechanism of the biological action of NO-OA is to our knowledge based on a reversible covalent reaction-Michael addition of nucleophilic amino acid residues of proteins. Since HSA is an important fatty acid transporter, a key question is whether NO-OA can bind covalently or non-covalently to HSA, similarly to oleic acid (OA), which can interact with the FA1-FA7 binding sites of the HSA molecule.

Characterization of Protocatechuate 4,5-Dioxygenase from Sphe3 and In Situ Reaction Monitoring in the NMR Tube.

The current study aims at the functional and kinetic characterization of protocatechuate (PCA) 4,5-dioxygenase (PcaA) from Sphe3. This is the first single subunit Type II dioxygenase characterized in Actinobacteria. RT-PCR analysis demonstrated that A and the adjacent putative genes implicated in the PCA -cleavage pathway comprise a single transcriptional unit.

On the molecular basis of HO/DMSO eutectic mixtures by using phenol compounds as molecular sensors: a combined NMR and DFT study.

NMR and DFT studies of phenol compounds as molecular sensors were carried out to investigate HO/DMSO eutectic mixtures at a molecular level. The experimental H NMR chemical shifts of the OH groups, δ(OH), of phenol, paracoumaric acid, and vanillic acid show maximum deshielding and, thus, hydrogen bond interactions in the range of mole fractions 0.20 < χ(DMSO) < 0.

DFT Calculations of H NMR Chemical Shifts of Geometric Isomers of Conjugated Linolenic Acids, Hexadecatrienyl Pheromones, and Model Triene-Containing Compounds: Structures in Solution and Revision of NMR Assignments.

A DFT study of the H NMR chemical shifts, δ(H), of geometric isomers of 18:3 conjugated linolenic acids (CLnAs), hexadecatrienyl pheromones, and model triene-containing compounds is presented, using standard functionals (B3LYP and PBE0) as well as corrections for dispersion interactions (B3LYP-D3, APFD, M06-2X and ωB97XD). The results are compared with literature experimental δ(H) data in solution. The closely spaced "inside" olefinic protons are significantly more deshielded due to short-range through-space HH steric interactions and appear close to or even beyond δ-values of aromatic systems.

NMR and Computational Studies as Analytical and High-Resolution Structural Tool for Complex Hydroperoxides and Diastereomeric -Hydroperoxides of Fatty Acids in Solution-Exemplified by Methyl Linolenate.

A combination of selective 1D Total Correlation Spectroscopy (TOCSY) and H-C Heteronuclear Multiple Bond Correlation (HMBC) NMR techniques has been employed for the identification of methyl linolenate primary oxidation products without the need for laborious isolation of the individual compounds. Complex hydroperoxides and diastereomeric -hydroperoxides were identified and quantified. Strongly deshielded C-O-O-H H-NMR resonances of diastereomeric -hydroperoxides in the region of 8.

DFT Calculations of H- and C-NMR Chemical Shifts of Geometric Isomers of Conjugated Linoleic Acid (18:2 ω-7) and Model Compounds in Solution.

A density functional theory (DFT) study of the H- and C-NMR chemical shifts of the geometric isomers of 18:2 ω-7 conjugated linoleic acid (CLA) and nine model compounds is presented, using five functionals and two basis sets. The results are compared with available experimental data from solution high resolution nuclear magnetic resonance (NMR). The experimental H chemical shifts exhibit highly diagnostic resonances due to the olefinic protons of the conjugated double bonds.

The NMR tube bioreactor.

Enzymes are pliable systems and core cellular components allowing the performance of several processes. They can also be utilized as "green" synthetic factories to generate bioactive therapeutic, diagnostic or theranostic compounds. Methods to enable the mapping of enzyme substrates as well as the understanding of the interactions of the formed products with target proteins could be of importance.

Simultaneous determination of artemisinin and its analogs and flavonoids in Artemisia annua crude extracts with the use of NMR spectroscopy.

Artemisia annua is a promising and potent antimalarial herbal drug. This activity has been ascribed to its component artemisinin, a sesquiterpene lactone. The ability to determine artemisinin and its known analogs in plant extracts is an especially difficult task because the compounds are present in low concentrations, are thermolabile, and lack ultraviolet or fluorescent chromophores.

Valorization of Carob Fruit Residues for the Preparation of Novel Bi-Functional Polyphenolic Coating for Food Packaging Applications.

The food industry has become interested in the development of innovative biomaterials with antioxidant and antimicrobial properties. Although several biopolymers have been evaluated for food packaging, the use of polyphenolic coatings has been unexplored. The purpose of this work was to develop an antioxidant and antimicrobial coating for food packaging through the polymerization of carob phenolics.