Synthesis of PEGylated amphiphilic block copolymers with pendant linoleic moieties by combining ring-opening polymerization and click chemistry.

This study focused on synthesizing and characterizing PEGylated amphiphilic block copolymers with pendant linoleic acid (Lin) moieties as an alternative to enhance their potential in drug delivery applications. The synthesis involved a two-step process, starting with ring-opening polymerization of ε-caprolactone (CL) and propargylated cyclic carbonate (MCP) to obtain PEG-b-P(CL-co-MCP) copolymers, which were subsequently modified via click chemistry. Various reaction conditions were explored to improve the yield and efficiency of the click chemistry step. The use of anisole as a solvent, N-(3-azidopropyl)linoleamide as a substrate, and a reaction temperature of 60°C proved to be highly efficient, achieving nearly 100% conversion at a low catalyst concentration. The resulting copolymers exhibited controlled molecular weights and low polydispersity, confirming the successful synthesis. Furthermore, click chemistry allows for the attachment of Lin moieties to the copolymer, enhancing its hydrophobic character, as deduced from their significantly lower critical micelle concentration than that of traditional PEG-b-PCL systems, which is indicative of enhanced stability against dilution. The modified copolymers exhibited improved thermal stability, making them suitable for applications that require high processing temperatures. Dynamic light scattering and transmission electron microscopy confirmed the formation of micellar structures with sizes below 100 nm and minimal aggregate formation. Additionally, 1H NMR spectroscopy in deuterated water revealed the presence of core-shell micelles, which provided higher kinetic stability against dilution.

Chemical Composition and Lipid Bioactive Components of Centaurea thracica Dwelling in Bulgaria.

Centaurea thracica (Janka) Hayek is a plant common in southern Bulgaria. The inflorescences were collected during June and September 2021, while their seeds were obtained in September 2021. The chemical and lipid composition of the inflorescences during the vegetation process of the plant were established. A significant decrease in total proteins (from 8.7 to 7.4%), glyceride oils (2.0-1.7%), and ash (4.5-4.2%) content was observed, while the amount of carbohydrates (72.3-77.2%) and fibers (28.7-35.8%) increased. During the vegetation of the plant, the content of oleic and linoleic acids increased up to 2-3 times, while the level of palmitic acid decreased. The lipids from the seeds were rich in oleic (53.0%) and palmitic (36.2%) acids. The tocopherol content in the oils of the inflorescences during vegetation increased from 58 to 110 mg/kg, and the content in the oil from the seeds was 260 mg/kg. The phospholipid content decreased during vegetation, and differences were observed in the composition between the inflorescences and the seeds. The high content of oleic acid, linoleic acid, tocopherols, and phospholipids determine the nutritional and biological value of the oils isolated from Centaurea thracica, and contribute to their potential use in various directions.

Influence mechanisms of linoleic acid and oleic acid on the gel properties of egg yolk protein.

BACKGROUND: Gel property is among the crucial functional properties of egg yolk (EY), which determines the texture and flavor of EY products. In the present study, the effects of two unsaturated fatty acids [monounsaturated fatty acid oleic acid (OA) and diunsaturated fatty acid linoleic acid (LA)] on the gel properties of EY protein were investigated. RESULTS: Compared with the blank group, the addition of LA and OA (10-50 g kg-1) improved the gel hardness (from 270.54 g to 385.85 g and 414.38 g, respectively) and viscosity coefficient (from 0.015 Pa.sn to 11.892 Pa.sn and 1.812 Pa.sn, respectively). The surface hydrophobicity of EY protein increased to a maximum value of 40 g kg-1 with the addition of both fatty acids (39.06 µg and 41.58 µg, respectively). However, excess unsaturated fatty acids (≥ 50 g kg-1) disrupted the completeness of the gel matrix and weakened the structural properties of the EY gel. CONCLUSION: Both fatty acids improved the gel properties of EY protein. At the same addition level, OA was superior to LA in improving gel properties. The present study provides a theoretical underpinning for the sensible application of unsaturated fatty acids in improving EY gel properties. © 2024 Society of Chemical Industry.

13C Electron Nuclear Double Resonance Spectroscopy-Guided Molecular Dynamics Computations Reveal the Structure of the Enzyme-Substrate Complex of an Active, N-Linked Glycosylated Lipoxygenase.

Lipoxygenase (LOX) enzymes produce important cell-signaling mediators, yet attempts to capture and characterize LOX-substrate complexes by X-ray co-crystallography are commonly unsuccessful, requiring development of alternative structural methods. We previously reported the structure of the complex of soybean lipoxygenase, SLO, with substrate linoleic acid (LA), as visualized through the integration of 13C/1H electron nuclear double resonance (ENDOR) spectroscopy and molecular dynamics (MD) computations. However, this required substitution of the catalytic mononuclear, nonheme iron by the structurally faithful, yet inactive Mn2+ ion as a spin probe. Unlike canonical Fe-LOXs from plants and animals, LOXs from pathogenic fungi contain active mononuclear Mn2+ metallocenters. Here, we report the ground-state active-site structure of the native, fully glycosylated fungal LOX from rice blast pathogen Magnaporthe oryzae, MoLOX complexed with LA, as obtained through the 13C/1H ENDOR-guided MD approach. The catalytically important distance between the hydrogen donor, carbon-11 (C11), and the acceptor, Mn-bound oxygen, (donor-acceptor distance, DAD) for the MoLOX-LA complex derived in this fashion is 3.4 ± 0.1 Å. The difference of the MoLOX-LA DAD from that of the SLO-LA complex, 3.1 ± 0.1 Å, is functionally important, although is only 0.3 Å, despite the MoLOX complex having a Mn-C11 distance of 5.4 Å and a "carboxylate-out" substrate-binding orientation, whereas the SLO complex has a 4.9 Å Mn-C11 distance and a "carboxylate-in" substrate orientation. The results provide structural insights into reactivity differences across the LOX family, give a foundation for guiding development of MoLOX inhibitors, and highlight the robustness of the ENDOR-guided MD approach to describe LOX-substrate structures.

Consensus mutagenesis and computational simulation provide insight into the desaturation catalytic mechanism for delta 6 fatty acid desaturase.

Fatty acid desaturase (FADS) generates double bond at a certain position of the corresponding polyunsaturated fatty acids (PUFAs) with high selectivity, the enzyme activity and PUFAs products of which are essential to biological systems and are associated with a variety of physiological diseases. Little is known about the structure of FADSs and their amino acid residues related to catalytic activities. Identifying key residues of Micromonas pusilla delta 6 desaturase (MpFADS6) provides a point of departure for a better understanding of desaturation. In this study, conserved amino acids were anchored through gene consensus analysis, thereby generating corresponding variants by site-directed mutagenesis. To achieve stable and high-efficiency expression of MpFADS6 and its variants in Saccharomyces cerevisiae, the key points of induced expression were optimized. The contribution of conserved residues to the function of enzyme was determined by analyzing enzyme activity of the variants. Molecular modeling indicated that these residues are essential to catalytic activities, or substrate binding. Mutants MpFADS6[Q409R] and MpFADS6[M242P] abolished desaturation, while MpFADS6[F419V] and MpFADS6[A374Q] significantly reduced catalytic activities. Given that certain residues have been identified to have a significant impact on MpFADS6 activities, it is put forward that histidine-conserved region III of FADS6 is related to electronic transfer during desaturation, while histidine-conserved regions I and II are related to desaturation. These findings provide new insights and methods to determine the structure, mechanism and directed transformation of membrane-bound desaturases.

Lipidomic and transcriptional analysis of the linoleoyl-omega-hydroxyceramide biosynthetic pathway in human psoriatic lesions.

A complex assembly of lipids including fatty acids, cholesterol, and ceramides is vital to the integrity of the mammalian epidermal barrier. The formation of this barrier requires oxidation of the substrate fatty acid, linoleic acid (LA), which is initiated by the enzyme 12R-lipoxygenase (LOX). In the epidermis, unoxidized LA is primarily found in long-chain acylceramides termed esterified omega-hydroxy sphingosine (EOS)/phytosphingosine/hydroxysphingosine (collectively EOx). The precise structure and localization of LOX-oxidized EOx in the human epidermis is unknown, as is their regulation in diseases such as psoriasis, one of the most common inflammatory diseases affecting the skin. Here, using precursor LC/MS/MS, we characterized multiple intermediates of EOx, including 9-HODE, 9,10-epoxy-13-HOME, and 9,10,13-TriHOME, in healthy human epidermis likely to be formed via the epidermal LOX pathways. The top layers of the skin contained more LA, 9-HODE, and 9,10,13-TriHOME EOSs, whereas 9,10-epoxy-13-HOME EOS was more prevalent deeper in the stratum corneum. In psoriatic lesions, levels of native EOx and free HODEs and HOMEs were significantly elevated, whereas oxidized species were generally reduced. A transcriptional network analysis of human psoriatic lesions identified significantly elevated expression of the entire biosynthetic/metabolic pathway for oxygenated ceramides, suggesting a regulatory function for EOx lipids in reconstituting epidermal integrity. The role of these new lipids in progression or resolution of psoriasis is currently unknown. We also discovered the central coordinated role of the zinc finger protein transcription factor, ZIC1, in driving the phenotype of this disease. In summary, long-chain oxygenated ceramide metabolism is dysregulated at the lipidomic level in psoriasis, likely driven by the transcriptional differences also observed, and we identified ZIC1 as a potential regulatory target for future therapeutic interventions.

Nanoparticle formulation of mycophenolate mofetil achieves enhanced efficacy against hepatocellular carcinoma by targeting tumour-associated fibroblast.

Hepatocellular carcinoma (HCC) is one of the most aggressive tumours with marked fibrosis. Mycophenolate mofetil (MMF) was well-established to have antitumour and anti-fibrotic properties. To overcome the poor bioavailability of MMF, this study constructed two MMF nanosystems, MMF-LA@DSPE-PEG and MMF-LA@PEG-PLA, by covalently conjugating linoleic acid (LA) to MMF and then loading the conjugate into polymer materials, PEG5k -PLA8k and DSPE- PEG2k , respectively. Hepatocellular carcinoma cell lines and C57BL/6 xenograft model were used to examine the anti-HCC efficacy of nanoparticles (NPs), whereas NIH-3T3 fibroblasts and highly-fibrotic HCC models were used to explore the anti-fibrotic efficacy. Administration of NPs dramatically inhibited the proliferation of HCC cells and fibroblasts in vitro. Animal experiments revealed that MMF-LA@DSPE-PEG achieved significantly higher anti-HCC efficacy than free MMF and MMF-LA@PEG-PLA both in C57BL/6 HCC model and highly-fibrotic HCC models. Immunohistochemistry further confirmed that MMF-LA@DSPE-PEG dramatically reduced cancer-associated fibroblast (CAF) density in tumours, as the expression levels of alpha-smooth muscle actin (α-SMA), fibroblast activation protein (FAP) and collagen IV were significantly downregulated. In addition, we found the presence of CAF strongly correlated with increased HCC recurrence risk after liver transplantation. MMF-LA@DSPE-PEG might act as a rational therapeutic strategy in treating HCC and preventing post-transplant HCC recurrence.

Linoleic acid and α-linolenic acid inhibit conjugative transfer of an IncX4 plasmid carrying mcr-1.

AIMS: The aim of this study was to determine the effects of unsaturated fatty acids on clinical plasmids. METHODS AND RESULTS: Two unsaturated fatty acids, linoleic acid (LA) and α-linolenic acid (ALA) at final concentration 0, 0·03, 0·3 and 3 mmol l-1 , respectively, were used to assess the effects on conjugative transfer of a mcr-1-harbouring plasmid pCSZ4 (IncX4) in conjugation experiment. The inhibitory mechanisms were analysed by molecular docking and the gene expression of virB11 was quantitated by qRT-PCR. Target plasmid diversity was carried out by TrwD/VirB11 homology protein sequence prediction analysis. Our results showed that LA and ALA inhibit plasmid pCSZ4 transfer by binding to the amino acid residues (Phe124 and Thr125) of VirB11 with dose-dependent effects. The expression levels of virB11 gene were also significantly inhibited by LA and ALA treatment. Protein homology analysis revealed a wide distribution of TrwD/VirB11-like genes among over 37 classes of plasmids originated from both Gram-negative and Gram-positive bacteria. CONCLUSIONS: This study demonstrates representing a diversity of plasmids that may be potentially inhibited by unsaturated fatty acids. SIGNIFICANCE AND IMPACT OF THE STUDY: Our work reported here provides additional support for application of curbing the spread of multiple plasmids by unsaturated fatty acids.

De novo biosynthesis of linoleic acid is widespread in parasitic wasps.

Linoleic acid (C18:2∆9,12 , LA) is an important metabolite with numerous essential functions for growth, health, and reproduction of organisms. It has long been assumed that animals lack ∆12-desaturases, the enzymes needed to produce LA from oleic acid (C18:1∆9 , OA). There is, however, increasing evidence that this is not generally true for invertebrates. In the insect order Hymenoptera, LA biosynthesis has been shown for only two parasitic wasp species of the so-called "Nasonia group," but it is unknown whether members of other taxa are also capable of synthesizing LA. Here, we demonstrate LA biosynthesis in 13 out of 14 species from six families of parasitic wasps by gas chromatography-mass spectrometry analysis using two different stable isotope labeling techniques. Females of the studied species converted topically applied fully 13 C-labeled OA into LA and/or produced labeled LA after feeding on fully 13 C-labeled α- d-glucose. These results indicate that ∆12-desaturases are widespread in parasitic Hymenoptera and confirm previous studies demonstrating that these insects are capable of synthesizing fatty acids de novo.

Novel quinolinone-pyrazoline hybrids: synthesis and evaluation of antioxidant and lipoxygenase inhibitory activity.

The present project deals with the investigation of structure-activity relationship of several quinolinone-chalcone and quinolinone-pyrazoline hybrids, in an effort to discover promising antioxidant and anti-inflammatory agents. In order to accomplish this goal, four bioactive hybrid quinolinone-chalcone compounds (8a-8d) were synthesized via an aldol condensation reaction, which were then chemically modified, forming fifteen new pyrazoline analogues (9a-9o). All the synthesized analogues were in vitro evaluated in terms of their antioxidant and soybean lipoxygenase (LOX) inhibitory activity. Among all the pyrazoline derivatives, compounds 9b and 9m were found to possess the best combined activity, whereas 9b analogue exhibited the most potent LOX inhibitory activity, with IC50 value 10 µM. The in silico docking results revealed that the synthetic pyrazoline analogue 9b showed high AutoDock Vina score (- 10.3 kcal/mol), while all the tested derivatives presented allosteric interactions with the enzyme.

The Protective Mechanism of Deuterated Linoleic Acid Involves the Activation of the Ca2+ Signaling System of Astrocytes in Ischemia In Vitro.

Ischemia-like (oxygen-glucose deprivation, OGD) conditions followed by reoxygenation (OGD/R) cause massive death of cerebral cortex cells in culture as a result of the induction of necrosis and apoptosis. Cell death occurs as a result of an OGD-induced increase in Ca2+ ions in the cytosol of neurons and astrocytes, an increase in the expression of genes encoding proapoptotic and inflammatory genes with suppression of protective genes. The deuterated form of linoleic polyunsaturated fatty acid (D4-Lnn) completely inhibits necrosis and greatly reduces apoptotic cell death with an increase in the concentration of fatty acid in the medium. It was shown for the first time that D4-Lnn, through the activation of the phosphoinositide calcium system of astrocytes, causes their reactivation, which correlates with the general cytoprotective effect on the cortical neurons and astrocytes in vitro. The mechanism of the cytoprotective action of D4-Lnn involves the inhibition of the OGD-induced calcium ions, increase in the cytosolic and reactive oxygen species (ROS) overproduction, the enhancement of the expression of protective genes, and the suppression of damaging proteins.

Chemometric Study of Fatty Acid Composition of Virgin Olive Oil from Four Widespread Greek Cultivars.

Virgin olive oil (VOO) is one of the key components of the Mediterranean diet owing to the presence of monounsaturated fatty acids and various bioactive compounds. These beneficial traits, which are usually associated with the cultivar genotype, are highlighting the demand of identifying characteristics of olive oil that will ensure its authenticity. In this work, the fatty acid (FA) composition of 199 VOO samples from Koroneiki, Megaritiki, Amfissis, and Manaki cultivars was determined and studied by chemometrics. Olive cultivar greatly influenced the FA composition, namely, oleic acid (from 75.36% for Amfissis to 65.81% for Megaritiki) and linoleic acid (from 13.35% for Manaki to 6.70% for Koroneiki). Spearman's rho correlation coefficients revealed differences and similarities among the olive oil cultivars. The use of the forward stepwise algorithm identified the FAs arachidonic acid, gadoleic acid, linoleic acid, α-linolenic acid, palmitoleic acid, and palmitic acid as the most significant for the differentiation of samples. The application of linear and quadratic cross-validation discriminant analysis resulted in the correct classification of 100.00% and 99.37% of samples, respectively. The findings demonstrated the special characteristics of the VOO samples derived from the four cultivars and their successful botanical differentiation based on FA composition.

The Chemical Composition of Oils and Cakes of Ochna serrulata (Ochnaceae) and Other Underutilized Traditional Oil Trees from Western Zambia.

Currently, the negative effects of unified and intensive agriculture are of growing concern. To mitigate them, the possibilities of using local but nowadays underused crop for food production should be more thoroughly investigated and promoted. The soybean is the major crop cultivated for vegetable oil production in Zambia, while the oil production from local oil-bearing plants is neglected. The chemical composition of oils and cakes of a three traditional oil plant used by descendants of the Lozi people for cooking were investigated. Parinari curatellifolia and Schinziophyton rautanenii oils were chiefly composed of α-eleostearic (28.58-55.96%), linoleic (9.78-40.18%), and oleic acid (15.26-24.07%), whereas Ochna serrulata contained mainly palmitic (35.62-37.31%), oleic (37.31-46.80%), and linoleic acid (10.61-18.66%); the oil yield was high (39-71%). S. rautanenii and O. serrulata oils were rich in γ-tocopherol (3236.18 µg/g, 361.11 µg/g, respectively). The O. serrulata oil also had a very distinctive aroma predominantly composed of p-cymene (52.26%), m-xylene (9.63%), γ-terpinene (9.07%), o-xylene (7.97), and limonene (7.23%). The cakes remaining after oil extraction are a good source of essential minerals, being rich in N, P, S, K, Ca, and Mg. These plants have the potential to be introduced for use in the food, technical, or pharmaceutical industries.

Utilization of Morchella esculenta-mediated green synthesis golden nanoparticles in biomedicine applications.

This study aimed to synthesize gold nanoparticles (AuNPs) by hot water extract in room conditions using edible Morchella esculenta (ME) and investigate the bioactive properties of the synthesized Morchella esculenta-based gold nanoparticles (ME-AuNPs). The characterization of the biologically synthesized ME-AuNPs was made using the ultraviolet-visible spectrophotometry, X-ray crystallography, scanning electron microscopy, Fourier transforms infrared spectroscopy, and energy dispersive X-ray spectrum methods. The ME-AuNPs, with a particle size of 16.51 nm, were found to have strong bioactive properties. The antioxidant activity of the ME-AuNPs attempted by metal chelating activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and the ß-carotene linoleate model system. The activities at 10 mg/mL were 82, 85, and 77% for the chelation of ferrous ions, DPPH scavenging, and ß-carotene linoleate tests, respectively. The ME-AuNPs also showed strong antimicrobial activity against various pathogen microorganisms and strong cytotoxic activity in the A549 and HepG2 cell lines. This study demonstrated the possibility of using a cheap and nontoxic fungal extract as a reducing and stabilizing agent for the synthesis of size-controlled, large-scale, and biocompatible AuNPs that could be used in future diagnostic and therapeutic applications.

Bioactive Compounds from Ephedra fragilis: Extraction Optimization, Chemical Characterization, Antioxidant and AntiGlycation Activities.

Response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize the extraction of bioactive compounds from Ephedra fragilis. The results suggested that extraction with 61.93% ethanol at 44.43 °C for 15.84 h was the best solution for this combination of variables. The crude ethanol extract (CEE) obtained under optimum extraction conditions was sequentially fractionated with solvents of increasing polarity. The content of total phenolic (TP) and total flavonoid (TF) as well as the antioxidant and antiglycation activities were measured. The phytochemical fingerprint profile of the fraction with the highest activity was characterized by using RP-HPLC. The ethyl acetate fraction (EAF) had the highest TP and TF contents and exhibited the most potent antioxidant and antiglycation activities. The Pearson correlation analysis results showed that TP and TF contents were highly significantly correlated with the antioxidant and antiglycation activities. Totally, six compounds were identified in the EAF of E. fragilis, including four phenolic acids and two flavonoids. Additionally, molecular docking analysis also showed the possible connection between identified bioactive compounds and their mechanisms of action. Our results suggest new evidence on the antioxidant and antiglycation activities of E. fragilis bioactive compounds that may be applied in the treatment and prevention of aging and glycation-associated complications.

Activation of Hair Cell Growth Factors by Linoleic Acid in Malva verticillata Seed.

Hair loss by excessive stress from work and lifestyle changes has become a growing concern, particularly among young individuals. However, most drugs for alopecia impose a plethora of side effects. We have found the powerful impact of Malva verticillata seed extracts on alleviating hair loss. This study further isolated effective chemicals in M. verticillata seed extracts by liquid silica gel column chromatography. Under the screening for the growth rate (%) of human follicles dermal papilla cells (HFDPCs), we identified linoleic acid (LA) and oleic acid in n-hexane of M. verticillate (MH)2 fraction. LA treatment activated Wnt/ß-catenin signaling and induced HFDPCs growth by increasing the expression of cell cycle proteins such as cyclin D1 and cyclin-dependent kinase 2. LA treatment also increased several growth factors, such as vascular endothelial growth factor, insulin-like growth factor-1, hepatocyte growth factor, and keratinocyte growth factor, in a dose-dependent manner. Besides, LA significantly inhibited Dickkopf-related protein expression (DKK-1), a primary alopecia signaling by dihydrotestosterone. Our findings suggest that LA treatment may alleviate a testosterone-induced signaling molecule and induces HFDPCs growth by activating Wnt/ß-catenin signaling.

Solid and fluid segments within the same molecule of stratum corneum ceramide lipid.

The outer layer of the skin, stratum corneum (SC) is an efficient transport barrier and it tolerates mechanical deformation. At physiological conditions, the majority of SC lipids are solid, while the presence of a small amount of fluid lipids is considered crucial for SC barrier and material properties. Here we use solid-state and diffusion nuclear magnetic resonance to characterize the composition and molecular dynamics of the fluid lipid fraction in SC model lipids, focusing on the role of the essential SC lipid CER EOS, which is a ceramide esterified omega-hydroxy sphingosine linoleate with very long chain. We show that both rigid and mobile structures are present within the same CER EOS molecule, and that the linoleate segments undergo fast isotropic reorientation while exhibiting extraordinarily slow self-diffusion. The characterization of this unusual self-assembly in SC lipids provides deepened insight into the molecular arrangement in the SC extracellular lipid matrix and the role of CER EOS linoleate in the healthy and diseased skin.

The Soybean Lipoxygenase-Substrate Complex: Correlation between the Properties of Tunneling-Ready States and ENDOR-Detected Structures of Ground States.

Hydrogen tunneling in enzymatic C-H activation requires a dynamical sampling among ground-state enzyme-substrate (E-S) conformations, which transiently generates a tunneling-ready state (TRS). The TRS is characterized by a hydrogen donor-acceptor distance (DAD) of 2.7 Å, ∼0.5 Å shorter than the dominant DAD of optimized ground states. Recently, a high-resolution, 13C electron-nuclear double-resonance (ENDOR) approach was developed to characterize the ground-state structure of the complex of the linoleic acid (LA) substrate with soybean lipoxygenase (SLO). The resulting enzyme-substrate model revealed two ground-state conformers with different distances between the target C11 of LA and the catalytically active cofactor [Fe(III)-OH]: the active conformer "a", with a van der Waals DAD of 3.1 Å between C11 and metal-bound hydroxide, and an inactive conformer "b", with a distance that is almost 1 Å longer. Herein, the structure of the E-S complex is examined for a series of six variants in which subtle structural modifications of SLO have been introduced either at a hydrophobic side chain near the bound substrate or at a remote residue within a protein network whose flexibility influences hydrogen transfer. A remarkable correlation is found between the ENDOR-derived population of the active ground-state conformer a and the kinetically derived differential enthalpic barrier for D versus H transfer, ΔEa, with the latter increasing as the fraction of conformer a decreases. As proposed, ΔEa provides a "ruler" for the DAD within the TRS. ENDOR measurements further corroborate the previous identification of a dynamical network coupling the buried active site of SLO to the surface. This study shows that subtle imperfections within the initial ground-state structures of E-S complexes are accompanied by compromised geometries at the TRS.

A protocol to obtain multidimensional quantum tunneling corrections derived from QM(DFT)/MM calculations for an enzyme reaction.

The significance of tunneling contributions to the rate constants of enzymatic reactions has been described at length using experimental evidence as well as theoretical computations. Within the frame of variational transition state theory (VTST), tunneling corrections are included using the so-called ground-state tunneling transmission coefficient. For the calculation of those enzymatic rate constants using the ensemble-averaged extension of VTST on QM/MM potential energy surfaces, the transmission coefficient at a given temperature is averaged over a set of coefficient values, each one obtained from an individual minimum energy path (MEP). However, the calculation of accurate QM/MM MEPs for tunneling calculations, also using a reliable QM method like DFT, is highly costly in enzyme models. For this reason, more affordable methodologies have been used. In this paper, we validate a feasible computational strategy to compute multidimensional tunneling corrections that describes better than cheaper alternatives the physics of the hydrogen abstraction from linoleic acid catalyzed by the enzyme 15-rLOX-1. Our recommendations to obtain better values of kinetic isotope effects and, especially, of rate constants are based on multidimensional small-curvature tunneling (SCT) coefficients derived from electrostatic embedding QM(DFT)/MM MEPs. The MEPs used must be calculated with a small enough step-size. Also, the number of gradients and Hessians along the reaction path must be checked to cover the whole tunneling region and to obtain converged adiabatic potential energy profiles. Distinguished reaction coordinates (DCPs) that are commonly used to describe enzyme reaction mechanisms are not adequate for tunneling calculations in such biological systems.

Vegetable butters and oils in skin wound healing: Scientific evidence for new opportunities in dermatology.

The use of vegetable butters and oils shows promising results in the treatment of skin wounds, as they have an effective impact on the phases of the wound-healing process through their antimicrobial, anti-inflammatory, and antioxidative activities and by promoting cell proliferation, increasing collagen synthesis, stimulating dermal reconstruction, and repairing the skin's lipid barrier function. In this article, in vitro and in vivo studies of argan (Argania spinosa), avocado (Persea americana), black cumin (Nigella sativa), calophyllum (Calophyllum inophyllum), coconut (Cocos nucifera), cranberry (Vaccinium macrocarpon), grape (Vitis vinifera), green coffee (Coffea arabica), lentisk (Pistacia lentiscus), linseed (Linum usitatissimum), lucuma (Pouteria lucuma), mango (Mangifera indica), olive (Olea europaea), pomegranate (Punica granatum), pumpkin (Cucurbita pepo), rapeseed (Brassica napus), sea buckthorn (Hippophae rhamnoides), and sunflower (Helianthus annuus) oils were reviewed. In many cases, vegetable oils proved to be more effective than synthetic wound-healing compounds used as controls. The fatty-acid components of vegetable oils are assumed to play a major role in the wound-healing process, in particular polyunsaturated fatty acids such as linoleic acid. Evidence shows that oils with a higher linoleic to oleic acid ratio are more effective for lipid barrier repair. However, in depth studies are needed to gain knowledge about vegetable oils' effects on the skin and vice versa.