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1.
J Agric Food Chem ; 71(43): 16371-16380, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37867462

RESUMO

Quantification of liposoluble micronutrients in large-scale vegetable oil samples is urgently needed, because their health benefits are increasingly emphasized. However, current analytical methods are limited to either labor-intensive preparation processes or time-consuming chromatography separation. In this work, an online oil matrix separation strategy for direct, rapid, and simultaneous determination of squalene, tocopherols, and phytosterols in walnut oil (WO) was developed on the basis of the lipid class separation mode of supercritical fluid chromatography. A single run was completed in 13 min containing 6 min of column cleaning and balancing. Satisfactory limit of detections (0.05-0.20 ng/mL), limit of quantifications (0.15-0.45 ng/mL), recoveries (70.61-101.44%), and matrix effects (78.43-91.62%) were achieved, indicating the reliability of this method. In addition, eight sterol esters were identified in WO, which have not previously been reported. The proposed method was applied to characterize the liposoluble micronutrient profile of WO samples obtained from different walnut cultivars, geographical origins, and processes.


Assuntos
Cromatografia com Fluido Supercrítico , Juglans , Fitosteróis , Esteróis/análise , Esqualeno/análise , Tocoferóis/química , Reprodutibilidade dos Testes , Fitosteróis/química , Espectrometria de Massas , Óleos de Plantas/química
2.
Geobiology ; 21(6): 743-757, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37563988

RESUMO

Tocopherols serve a critical role as antioxidants inhibiting lipid peroxidation in photosynthetic organisms, yet are seldom used in geobiological investigations. The ubiquity of tocopherols in all photosynthetic lifeforms is often cited as an impediment to any diagnostic paleoenvironmental potential, while the inability to readily analyze these compounds via conventional methods, such as gas chromatography-mass spectrometry, further diminishes the capacity to serve as useful 'biomarkers'. Here, we analyzed an exceptionally preserved black shale sequence from the Demerara Rise that spans Oceanic Anoxic Event 2 (OAE-2) to reexamine the significance of tocopherols and associated derivatives (i.e. tocol derivatives) in ancient sediments. Tocol derivatives were analyzed via liquid chromatography-quadrupole time-of-flight-mass spectrometry and included tocopherols, a methyltrimethyltridecylchroman, and the first reported detection of tocopherol quinones and methylphytylbenzoquinones in the geologic record. Strong correlations between tocol derivatives were observed over the studied interval. Tocol derivative concentrations and ratios, which normalized tocopherols to potential derivatives, revealed absolute and relative increases in tocopherols as exclusive features of OAE-2 that can be explained by two possible mechanisms related to tocopherol production and preservation. The development of photic zone euxinia during OAE-2 likely forced an upward migration of oxygenic photoautotrophs, increasing oxidative stress that elicited heightened tocopherol biosynthesis. However, shoaling euxinic conditions may have simultaneously acted to enhance tocopherol preservation given the relatively high lability of tocopherols in the water column. Both scenarios could produce the observed stratigraphic distribution of tocol derivatives in this study, although the elevated tocopherol concentrations that define OAE-2 at the Demerara Rise are primarily attributed to enhanced tocopherol production by shoaling phytoplanktonic communities. Thus, the occurrence of tocopherols and associated derivatives in sediments and rocks of marine origin is likely indicative of shallow-water anoxia, tracking the phytoplanktonic response to the abiotic stresses associated with vertical fluctuations in pelagic redox.


Assuntos
Fitoplâncton , Tocoferóis , Humanos , Tocoferóis/química , Oxirredução , Hipóxia , Água
3.
Plant Commun ; 4(5): 100598, 2023 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-37029487

RESUMO

Tocopherols (vitamin E) play essential roles in human health because of their antioxidant activity, and plant-derived oils are the richest sources of tocopherols in the human diet. Although soybean (Glycine max) is one of the main sources of plant-derived oil and tocopherol in the world, the relationship between tocopherol and oil in soybean seeds remains unclear. Here, we focus on dissecting tocopherol metabolism with the long-term goal of increasing α-tocopherol content and soybean oil quality. We first collected tocopherol and fatty acid profiles in a soybean population (>800 soybean accessions) and found that tocopherol content increased during soybean domestication. A strong positive correlation between tocopherol and oil content was also detected. Five tocopherol pathway-related loci were identified using a metabolite genome-wide association study strategy. Genetic variations in three tocopherol pathway genes were responsible for total tocopherol content and composition in the soybean population through effects on enzyme activity, mainly caused by non-conserved amino acid substitution or changes in gene transcription level. Moreover, the fatty acid regulatory transcription factor GmZF351 directly activated tocopherol pathway gene expression, increasing both fatty acid and tocopherol contents in soybean seeds. Our study reveals the functional differentiation of tocopherol pathway genes in soybean populations and provides a framework for development of new soybean varieties with high α-tocopherol content and oil quality in seeds.


Assuntos
Ácidos Graxos , Tocoferóis , Humanos , Tocoferóis/análise , Tocoferóis/química , Tocoferóis/metabolismo , Ácidos Graxos/metabolismo , /metabolismo , alfa-Tocoferol/análise , alfa-Tocoferol/metabolismo , Estudo de Associação Genômica Ampla , Óleos de Plantas/metabolismo , Sementes/genética
4.
Food Chem ; 414: 135719, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-36808031

RESUMO

The purpose of this research was to effectively migrate tocopherols (T) to the oil-water interface layer (oxidation site) by combining hydrophobic T with amphiphilic phospholipids (P) to improve the oxidative stability of O/W emulsions. Firstly, it was confirmed that the antioxidant ability of TP combinations exhibited synergistic effects in O/W emulsions by measuring lipid hydroperoxides and thiobarbituric acid-reactive species. Moreover, the introduction of P into O/W emulsions to improve the distribution of T at the interfacial layer was confirmed by centrifugation and confocal microscopy methods. Subsequently, the possible mechanisms of synergistic interaction between T and P were described by fluorescence spectroscopy, isothermal titration calorimetry, electron spin resonance, quantum chemical methods and the variation of minor constituents during storage. This research revealed an in-depth insight into the antioxidant interaction mechanism of TP combinations using experimental and theoretical approaches, which provided theoretical guidance for developing emulsion products with better oxidative stability.


Assuntos
Antioxidantes , Tocoferóis , Tocoferóis/química , Antioxidantes/química , Emulsões/química , Fosfolipídeos , Oxirredução , Estresse Oxidativo , Água/química
5.
Food Chem ; 398: 133945, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-35986990

RESUMO

Olive oils from seven Portuguese regions were selected to study the effect of the geographical origin on the oils' composition. Quality parameters, fatty acids, tocopherols, hydroxytyrosol and tyrosol derivatives, and oxidative stability were evaluated. All olive oils could be classified as extra virgin, and the geographical origin significantly affected the oils chemical composition. Principal component analysis further confirmed the significant impact of the geographical origin on the composition and, indirectly, on stability of the oils, showing that the evaluated parameters could be used as markers for geographical origin identification. Alternatively, Fourier transform infrared spectroscopy was applied, allowing to establish a linear discriminant model that correctly identified the geographical origin of the olive oils with a mean sensitivity of 99 ± 3 % (internal validation), confirming the impact of the oil origin on its characteristics. This finding allowed foreseeing the future application of the spectroscopy approach as a green, fast and non-invasive authentication tool.


Assuntos
Galega , Ácidos Graxos/análise , Azeite de Oliva/química , Óleos de Plantas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tocoferóis/química
6.
Molecules ; 27(19)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36235100

RESUMO

Free and esterified (bound) tocopherols, tocotrienols and other tocochromanol-related compounds, often referred to "tocols", are lipophilic antioxidants of great importance for health. For instance, α-tocopherol is the only tocochromanol with vitamin E activity, while tocotrienols have a positive impact on health and are proposed in the prevention and therapy of so-called modern diseases. Tocopherols, tocotrienols and plastochromanol-8 are the most well-known tocochromanols; in turn, knowledge about tocodienols, tocomonoenols, and other rare tocochromanol-related compounds is limited due to several challenges in analytical chemistry and/or low concentration in plant material. The presence of free, esterified, and non-extractable tocochromanols in plant material as well as their biological function, which may be of great scientific, agricultural and medicinal importance, is also poorly studied. Due to the lack of modern protocols as well as equipment and tools, for instance, techniques suitable for the efficient and simultaneous chromatographical separation of major and minor tocochromanols, the topic requires attention and new solutions, and/or standardization, and proper terminology. This review discusses the advantages and disadvantages of different chromatographic techniques, tools and approaches used for the separation and detection of different tocochromanols in plant material and foodstuffs. Sources of tocochromanols and procedures for obtaining different tocochromanol analytical standards are also described. Finally, future challenges are discussed and perspective green techniques for tocochromanol determination are proposed along with best practice recommendations. The present manuscript aims to present key aspects and protocols related to tocochromanol determination, correct identification, and the interpretation of obtained results.


Assuntos
Tocotrienóis , Antioxidantes , Tocoferóis/química , Tocotrienóis/análise , Vitamina E , alfa-Tocoferol
7.
J Food Sci ; 87(10): 4363-4378, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36102045

RESUMO

In this study, the high voltage electric field (HVEF) method was used for deodorization of sunflower oil to omit drawbacks of an established industrial method including long time, high energy, chemicals and water consumption, loss of bioactive compounds, and formation of some contaminants due to exposure to heat. Response surface methodology (RSM) was employed to find the optimal values of processing parameters. The effects of voltage (5-15 kV), clay (0-1%), electrolyte concentration (0-50 mM), the number of electrodes (1-5 pairs), and electrodes distance (1-3 cm) on the volatile compounds and tocopherols content were investigated by HS-SPME-GC/MS and HPLC, respectively. The optimal processing conditions were determined to be a voltage of 5 kV, a distance of 1 cm between the electrodes and a number of five pairs of electrodes. The amount of bleaching clay and electrolyte concentration were zero under optimal conditions. The refining process by HVEF removed 32.33% of the volatile compounds from crude sunflower oil, while the industrial refining process reduced the volatile compounds by only 17.78%. Results indicated no change was observed in the tocopherols content of refined sunflower oil by HVEF method. Based on PCA results, HVEF-treated sample not only contained the lowest concentration of volatile compounds but also was the most similar to crude sample in terms of volatile compounds composition. PRACTICAL APPLICATION: The oil refining process consists of four main stages, the last of which is deodorization. This step involves injecting steam at a temperature of about 240°C, under vacuum for about 50 min. High voltage electric field (HVEF) was able to reduce the number of volatile compounds, while no change was made in the tocopherol content of sunflower oil samples. It also does not form contaminant such as 3-monochloropropane-1,2-diol fatty acid esters and glycidyl fatty acid esters. There is no need to apply the vacuum in HVEF refining, which reduces the production cost and makes the process flow straightforward as well as rapid. This research helps to propagate green refining procedures of vegetable oils in food plants.


Assuntos
alfa-Cloridrina , alfa-Cloridrina/química , Óleo de Girassol , Ésteres/química , Vapor , Argila , Óleos de Plantas/química , Tocoferóis/química , Ácidos Graxos
8.
J Fluoresc ; 32(6): 1991-1998, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35798985

RESUMO

The spectral and luminescence properties of linseed oils with different background have been studied. High informativity of oil fluorophores (phenols, tocopherols, polyunsaturated fatty acids, vitamins, pigments) as to their native state depending on the influence of various destructive factors: extended storage period of oil (three years), exposure to sunlight for 50 h and contact with temperatures in the range of 60 ºC > t > 46 ºC was registered.It was revealed that: 1. Exposure of linseed oil to sunlight for 50 h and contact with temperatures 60 ºC > t > 46 ºC during the process of oil extraction don't lead to visible changes in the structures of their luminescence spectra and luminescence excitation spectra. 2. Long storage period of oil (> 3 years) leads to: (a) decomposition of phenols, tocopherols, polyunsaturated fatty acids (linoleic, linolenic, arachidonic), vitamins (B2, E, carotene), accompanied by the appearance of emission bands with maxima λmax = 350, 370, 390, 425, 440, 470, 520 nm, which are attributed to the products of their oxidation, increase of their luminescence intensity and changes in the structure of the luminescence excitation spectra of fluorophores: phenols, tocopherols, polyunsaturated fatty acids (linoleic, linolenic, arachidonic) and vitamins (B2, E, carotene); (b) decrease in the intensity of the luminescence bands of phenol, tocopherol, carotene and chlorophyll pigment.


Assuntos
Linho , Óleo de Semente do Linho , Óleos de Plantas/química , Luminescência , Fenol , Tocoferóis/química , Ácidos Graxos Insaturados , Fenóis , Vitaminas , Carotenoides , Clorofila , Ácidos Graxos
9.
Compr Rev Food Sci Food Saf ; 21(2): 964-998, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35181987

RESUMO

Vitamin E is a group of isoprenoid chromanols with different biological activities. It comprises eight oil-soluble compounds: four tocopherols, namely, α-, ß-, γ-, and δ-tocopherols; and four tocotrienols, namely, α-, ß-, γ, and δ-tocotrienols. Vitamin E isomers are well-known for their antioxidant activity, gene-regulation effects, and anti-inflammatory and nephroprotective properties. Considering that vitamin E is exclusively synthesized by photosynthetic organisms, animals can only acquire it through their diet. Plant-based food is the primary source of vitamin E; hence, oils, nuts, fruits, and vegetables with high contents of vitamin E are mostly consumed after processing, including industrial processes and home-cooking, which involve vitamin E profile and content alteration during their preparation. Accordingly, it is essential to identify the vitamin E content and profile in foodstuff to match daily intake requirements. This review summarizes recent advances in vitamin E chemistry, metabolism and metabolites, current knowledge on their contents and profiles in raw and processed plant foods, and finally, their modern developments in analytical methods.


Assuntos
Tocotrienóis , Vitamina E , Animais , Antioxidantes/química , Tecnologia de Alimentos , Tocoferóis/química , Tocoferóis/metabolismo , Tocotrienóis/análise , Tocotrienóis/química , Tocotrienóis/metabolismo
10.
G3 (Bethesda) ; 12(4)2022 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-35150257

RESUMO

Tocopherols are antioxidants that preserve oil lipids against oxidation and serve as a natural source of vitamin E in the human diet. Compared with other major oilseeds like rapeseed and soybean, sunflower (Helianthus annuus L.) exhibits low phenotypic diversity of tocopherol composition, both in wild and cultivated accessions from germplasm collections. Two major mutations that alter tocopherol composition were identified in genetic collections, and several studies suggested additional loci controlling tocopherol composition, with their expression possibly depending on the genetic background. In the present study, we performed QTL mapping of tocopherol composition in two independent F2 crosses between lines with contrasting tocopherol composition from the Pustovoit All-Russia Research Institute of Oil Crops (VNIIMK) collection. We used genotyping-bysequencing (GBS) to construct single nucleotide polymorphism-based genetic maps, and performed QTL mapping using quantitative and qualitative encoding for phenotypic traits. Our results support the notion that the tocopherol composition in the assessed crosses is controlled by two loci. We additionally selected and validated two single nucleotide polymorphism markers for each cross which could be used for marker-assisted selection.


Assuntos
Helianthus , Óleos de Plantas , Tocoferóis , Mapeamento Cromossômico , Helianthus/genética , Fenótipo , Óleos de Plantas/química , Tocoferóis/química
11.
J Am Chem Soc ; 144(7): 3285-3296, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35156815

RESUMO

Micelles on the surfaces of individual metallic zinc particles are imaged by fluorescence microscopy with sensitivity up to single micelles. These micelles are made fluorescent to enable imaging, through the incorporation of boron dipyrromethene fluorophores as representative organic molecular "cargo". Highlighting an advantage of this in situ and sensitive fluorescence technique, the same micelles are not visible by ex situ scanning electron microscopy/energy dispersive X-ray spectroscopy analysis. Examination of micellar solutions with zinc reveals an aging process: micelles do not immediately adhere to the zinc surfaces upon mixing but rather build up over time. Furthermore, at longer times, smaller zinc particles become fully encased in micelle "shells". Once adhered, micelles remain in the local regions of the zinc surface for the duration of the imaging experiments (>2 h). Single micelles are imaged in solution, and their molecular contents are characterized. Two-color fluorescence crossover experiments show that micelles adhered to the surface of the zinc exchange molecular contents with micelles in solution, achieving molecular exchange equilibrium in ∼2.5 h. Unique (non-ensemble averaged) exchange kinetics are displayed by micelles at different locations on the zinc surface, consistent with exchange kinetics of single micelles or small local clusters of micelles. The aging of the micellar solutions and the rate of exchange while on the surface of the zinc suggest that micelle mass transport processes may contribute to overall reaction barriers in sustainable organozinc cross-coupling reactions in micellar water. The observed aging of the system suggests routes for improvement of preparative, bench-scale synthetic reactions involving micellar preparations of organozinc compounds.


Assuntos
Micelas , Compostos Organometálicos/química , Zinco/química , Adesividade , Compostos de Boro/química , Corantes Fluorescentes/química , Hidrocarbonetos Iodados/química , Microscopia de Fluorescência , Tensoativos/química , Tocoferóis/química , Água/química
12.
Molecules ; 27(4)2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35209222

RESUMO

Two novel microwave-assisted extraction (MAE) methods were developed for the isolation of phenols and tocopherols from pistachio nuts. The extracts were analyzed by reversed-phase high-pressure liquid chromatography coupled with a UV detector (RP-HPLC-UV). In total, eighteen pistachio samples, originating from Greece and Turkey, were analyzed and thirteen phenolic compounds, as well as α-tocopherol, (ß + γ)-tocopherol, and δ-tocopherol, were identified. The analytical methods were validated and presented good linearity (r2 > 0.990) and a high recovery rate over the range of 82.4 to 95.3% for phenols, and 93.1 to 96.4% for tocopherols. Repeatablility was calculated over the range 1.8-5.8%RSD for intra-day experiments, and reproducibility over the range 3.2-9.4%RSD for inter-day experiments, respectively. Principal component analysis (PCA) was employed to analyze the differences between the concentrations of the bioactive compounds with respect to geographical origin, while agglomerative hierarchical clustering (AHC) was used to cluster the samples based on their similarity and according to the geographical origin.


Assuntos
Fracionamento Químico , Quimiometria/métodos , Cromatografia Líquida de Alta Pressão , Micro-Ondas , Nozes/química , Compostos Fitoquímicos/análise , Pistacia/química , Fracionamento Químico/métodos , Análise por Conglomerados , Grécia , Fenóis/análise , Pistacia/classificação , Tocoferóis/análise , Tocoferóis/química , Turquia
13.
Nat Prod Res ; 36(21): 5524-5529, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34933616

RESUMO

From an ethyl acetate-soluble fraction of the leaves of Muntingia calabura, one new trimeric δ-tocopherol derivative named as tocomuntin A (1), together with three known δ-tocopherol derivatives (2-4) were isolated. Their structures were elucidated based on the interpretation of NMR and MS spectroscopic data. In this work, δ-tocopherol (3) was found to have α-glucosidase inhibitory activity for the first time (IC50, 47.3 µM).


Assuntos
Magnoliopsida , Extratos Vegetais , Folhas de Planta , Tocoferóis , Extratos Vegetais/química , Folhas de Planta/química , Magnoliopsida/química , Tocoferóis/química , Inibidores de Glicosídeo Hidrolases/química
14.
Carbohydr Polym ; 276: 118734, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34823770

RESUMO

Our previous study proposed preparation method of tocopherol (Toc) loaded ethyl cellulose (EC) particles as antioxidant due to instability of Toc under high temperature. The present study aimed to explore the antioxidant mechanism of loaded particles. Results showed that loaded particles prepared by EC of different viscosities (EC9, EC70, EC200) had antioxidative effect, and the antioxidant activity increased with EC viscosity. Fourier transform infrared analysis demonstrated that the interaction between EC and tocopherol was mainly hydrogen bond. Loaded particles retained effectively the thermal degradation of Toc and thus enhanced the antioxidant activity. Further investigation into thermal oxidation of EC inferred the possible antioxidative mechanism included two aspects. One was that Toc was fixed in the network structure of loaded particles formed by EC to provide a barrier for avoiding degradation. Another was that EC and Toc acted on different stages of lipid oxidation, playing the antioxidative effect together.


Assuntos
Antioxidantes/química , Celulose/análogos & derivados , Óleo de Soja/química , Tocoferóis/química , Celulose/química , Ligação de Hidrogênio , Oxirredução , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Temperatura , Viscosidade
15.
J Sci Food Agric ; 102(1): 185-197, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34061348

RESUMO

BACKGROUND: Juices are currently a fast-growing segment in the fruit and vegetable industry sector. However, there are still no reports on the diversity of the phytochemical profile and health-promoting properties of commercial sea buckthorn (Hippophaë rhamnoides) juices. This study aimed to identify and quantify phytoprostanes, phytofurans by ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS), tocopherols, tocotrienols by ultra-performance liquid chromatography coupled with a fluorescence detector (UPLC-FL), carotenoids, and free amino acids by ultra-performance liquid chromatography coupled with a photodiode detector-quadrupole and tandem time-of-flight mass spectrometry (UPLC-PDA-Q/TOF-MS), and assess their anti-cholinergic, anti-diabetic, anti-obesity, anti-inflammatory, and antioxidant potential by in vitro assays of commercial sea buckthorn juices. RESULTS: Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) in sea buckthorn juices were identified for the first time. Juices contained eight F1 -, D1 -, B1 - and L1 -phytoprostanes and one phytofuran (32.31-1523.51 ng and up to 101.47 µg/100 g dry weight (DW)), four tocopherol congeners (22.23-94.08 mg 100 g-1 DW) and three tocotrienols (5.93-25.34 mg 100 g-1 DW). Eighteen carotenoids were identified, including ten xanthophylls, seven carotenes and phytofluene, at a concentration of 133.65 to 839.89 mg 100 g-1 DW. Among the 20 amino acids (175.92-1822.60 mg 100 g-1 DW), asparagine was dominant, and essential and conditionally essential amino acids constituted 11 to 41% of the total. The anti-enzyme and antioxidant potential of juices correlated selectively with the composition. CONCLUSION: Sea buckthorn juice can be a valuable dietary source of vitamins E and A, oxylipins and amino acids, used in the prevention of metabolic syndrome, inflammation, and neurodegenerative processes. The differentiation of the composition and the bioactive potential of commercial juices indicate that, for the consumer, it should be important to choose juices from the declared berry cultivars and crops. © 2021 Society of Chemical Industry.


Assuntos
Carotenoides/química , Sucos de Frutas e Vegetais/análise , Hippophae/química , Extratos Vegetais/química , Tocoferóis/química , Tocotrienóis/química , Aminoácidos/química , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Frutas/química , Espectrometria de Massas em Tandem
16.
Compr Rev Food Sci Food Saf ; 21(1): 642-688, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34889039

RESUMO

Lipid oxidation is a major concern in the food, cosmetic, and pharmaceutical sectors. The degradation of unsaturated lipids affects the nutritional, physicochemical, and organoleptic properties of products and can lead to off-flavors and to the formation of potentially harmful oxidation compounds. To prevent or slow down lipid oxidation, different antioxidant additives are used alone or in combination to achieve the best possible efficiency with the minimum possible quantities. In manufactured products, that is, heterogeneous systems containing lipids as emulsions or bulk phase, the efficiency of an antioxidant is determined not only by its chemical reactivity, but also by its physical properties and its interaction with other compounds present in the products. The antioxidants most widely used on the industrial scale are probably tocopherols, either as natural extracts or pure synthetic molecules. Considerable research has been conducted on their antioxidant activity, but results regarding their efficiency are contradictory. Here, we review the known mechanisms behind the antioxidant activity of tocopherols and discuss the chemical and physical features that determine their efficacy. We first describe their chemical reactivity linked with the main factors that modulate it between efficient antioxidant capacity and potential prooxidant effects. We then describe their chemical interactions with other molecules (phenolic compounds, metals, vitamin C, carotenes, proteins, and phospholipids) that have potential additive, synergistic, or antagonist effects. Finally, we discuss other physical parameters that influence their activity in complex systems including their specific interactions with surfactants in emulsions and their behavior in the presence of association colloids in bulk oils.


Assuntos
Antioxidantes , Tocoferóis , Antioxidantes/química , Antioxidantes/farmacologia , Emulsões/química , Oxirredução , Óleos de Plantas/química , Tocoferóis/química
17.
Molecules ; 26(23)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34885766

RESUMO

In this study, an overall survey regarding the determination of several bioactive compounds in olive fruit is presented. Two methodologies were developed, one UPLC-Q-TOF-MS method for the determination of olive fruit phenolic compounds and one HPLC-DAD methodology targeting the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, ß, -γ, δ-) and squalene. Target and suspect screening workflows were developed for the thorough fingerprinting of the phenolic fraction of olives. Both methods were validated, presenting excellent performance characteristics, and can be used as reliable tools for the monitoring of bioactive compounds in olive fruit samples. The developed methodologies were utilized to chemical characterize the fruits of the Kolovi olive variety, originating from the island of Lesvos, North Aegean Region, Greece. Twenty-five phenolic compounds were identified and quantified in Kolovi olives with verbascoside, hydroxytyrosol, oleacein and oleomissional found in significantly high concentrations. Moreover, 12 new bioactive compounds were identified in the samples using an in-house suspect database. The results of pigments analysis suggested that Kolovi variety should be characterized as low pigmentation, while the tocopherol and squalene content was relatively high compared to other olive varieties. The characterization of Kolovi olive bioactive content highlighted the high nutritional and possible economic value of the Kolovi olive fruit.


Assuntos
Aldeídos/isolamento & purificação , Glucosídeos/química , Olea/química , Fenóis/química , Fenóis/isolamento & purificação , Compostos Fitoquímicos/química , Aldeídos/química , Cromatografia Líquida de Alta Pressão , Frutas/química , Glucosídeos/isolamento & purificação , Grécia , Iridoides/química , Iridoides/isolamento & purificação , Azeite de Oliva/química , Azeite de Oliva/isolamento & purificação , Álcool Feniletílico/análogos & derivados , Compostos Fitoquímicos/isolamento & purificação , Espectrometria de Massas em Tandem , Tocoferóis/química , Tocoferóis/isolamento & purificação
18.
Molecules ; 26(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34500642

RESUMO

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.


Assuntos
Ochnaceae/química , Óleos de Plantas/química , Árvores/química , Culinária/métodos , Ácidos Graxos/química , Ácido Linoleico/química , Ácido Oleico/química , Sementes/química , Tocoferóis/química , Zâmbia , gama-Tocoferol/química
19.
Molecules ; 26(18)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34577176

RESUMO

Percutaneous coronary intervention (PCI) has long remained the gold standard therapy to restore coronary blood flow after acute myocardial infarction (AMI). However, this procedure leads to the development of increased production of reactive oxygen species (ROS) that can exacerbate the damage caused by AMI, particularly during the reperfusion phase. Numerous attempts based on antioxidant treatments, aimed to reduce the oxidative injury of cardiac tissue, have failed in achieving an effective therapy for these patients. Among these studies, results derived from the use of vitamin C (Vit C) have been inconclusive so far, likely due to suboptimal study designs, misinterpretations, and the erroneous conclusions of clinical trials. Nevertheless, recent clinical trials have shown that the intravenous infusion of Vit C prior to PCI-reduced cardiac injury biomarkers, as well as inflammatory biomarkers and ROS production. In addition, improvements of functional parameters, such as left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume, showed a trend but had an inconclusive association with Vit C. Therefore, it seems reasonable that these beneficial effects could be further enhanced by the association with other antioxidant agents. Indeed, the complexity and the multifactorial nature of the mechanism of injury occurring in AMI demands multitarget agents to reach an enhancement of the expected cardioprotection, a paradigm needing to be demonstrated. The present review provides data supporting the view that an intravenous infusion containing combined safe antioxidants could be a suitable strategy to reduce cardiac injury, thus improving the clinical outcome, life quality, and life expectancy of patients subjected to PCI following AMI.


Assuntos
Antioxidantes/química , Ácido Ascórbico/química , Infarto do Miocárdio/metabolismo , Substâncias Protetoras/química , Traumatismo por Reperfusão/tratamento farmacológico , Acetilcisteína/farmacologia , Animais , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Biomarcadores/metabolismo , Desferroxamina/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Humanos , Masculino , Estresse Oxidativo/fisiologia , Intervenção Coronária Percutânea , Polifenóis/farmacologia , Substâncias Protetoras/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Traumatismo por Reperfusão/metabolismo , Transdução de Sinais , Volume Sistólico/fisiologia , Tocoferóis/química , Tocoferóis/farmacologia , Função Ventricular Esquerda/fisiologia
20.
J Oleo Sci ; 70(8): 1051-1058, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34349086

RESUMO

This study aimed to examine the chemical composition of wheat germ oil extracted by three different methods, and to evaluate its inhibitory effect on the cyclooxygenase and proteinase activities. The results showed that the contents of policosanols, tocopherols and phytosterols were affected by the extraction procedure. However, the fatty acid composition of the different oil extracts was nearly the same. Among the tested oils samples, cold pressed oil exhibited the strongest inhibitory activity against proteinase (93.4%, IC50 =195.7 µg/mL) and cyclooxygenase 1 (80.5%, IC50 =58.6 µg/mL). Furthermore, the cold pressed oil had the highest content of octacosanol, ß-sitosterol and α-linolenic acid, suggesting that those bioactive compounds could be essential for the potent ani-cyclooxygenase activity. The present data revealed that wheat germ oil contained cyclooxygenase and trypsin inhibitors, which are the promising therapeutic target for the treatment of various inflammatory diseases. Thus, wheat germ oil might be used to develop functional foods and pharmaceutic products for the human health.


Assuntos
Anti-Inflamatórios/química , Inibidores de Ciclo-Oxigenase/química , Óleos de Plantas/química , Triticum/química , Inibidores da Tripsina/química , Anti-Inflamatórios/análise , Anti-Inflamatórios/isolamento & purificação , Inibidores de Ciclo-Oxigenase/análise , Inibidores de Ciclo-Oxigenase/isolamento & purificação , Álcoois Graxos/análise , Álcoois Graxos/química , Álcoois Graxos/isolamento & purificação , Extração Líquido-Líquido/métodos , Fitosteróis/análise , Fitosteróis/química , Fitosteróis/isolamento & purificação , Óleos de Plantas/análise , Óleos de Plantas/isolamento & purificação , Tocoferóis/análise , Tocoferóis/química , Tocoferóis/isolamento & purificação , Inibidores da Tripsina/análise , Inibidores da Tripsina/isolamento & purificação
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