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1.
Enzyme Microb Technol ; 175: 110409, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38335559

RESUMO

The solvent-free esterification of the free fatty acids (FFAs) obtained by the hydrolysis of castor oil (a non-edible vegetable oil) with 2-ethyl-1-hexanol (a branched fatty alcohol) was catalyzed by different free lipases. Eversa Transform 2.0 (ETL) features surpassed most commercial lipases. Some process parameters were optimized by the Taguchi method (L16'). As a result, a conversion over 95% of the FFAs of castor oil into esters with lubricants properties was achieved under optimized reaction conditions (15 wt% of biocatalyst content, 1:4 molar ratio (FFAs/alcohol), 30 °C, 180 rpm, 96 h). The substrates molar ratio had the highest influence on the dependent variable (conversion at 24 h). FFAs/2-ethyl-1-hexanol esters were characterized regarding the physicochemical and tribological properties. Interestingly, the modification of the FFAs with 2-ethyl-1-hexanol by ETL increased the oxidative stability of the FFAs feedstock from 0.18 h to 16.83 h. The biolubricants presented a lower friction coefficient than the reference commercial mineral lubricant (0.052 ± 0.07 against 0.078 ± 0.04). Under these conditions, ETL catalyzed the oligomerization of ricinoleic acid (a hydroxyl fatty acid) into estolides, reaching a conversion of 25.15% of the initial FFAs (for the first time).


Assuntos
Óleo de Rícino , Ácidos Graxos não Esterificados , Hexanóis , Esterificação , Ésteres/química , Ácidos Graxos/química , Lipase/metabolismo , Etanol , Catálise , Enzimas Imobilizadas/química
2.
Sci Rep ; 14(1): 3416, 2024 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-38341447

RESUMO

Synthetic ester oils are widely used in many applications due to their ideal cleaning properties, lubricating performance and assured polarity. The majority of esters oils are more biodegradable. than any other base stock. For instance, oil soluble polyalkyleneglycols (PAGs) or polyalphaolephins (PAOs), are only biodegradable in the lower viscosity grades. The goal of this study is to create some synthetic base oils by two major protocols; the first is esterifying valeric acid with various glycols (ethylene glycol, propylene glycol, butylene glycol and poly (ethylene glycol 400). The second involves esterification of propanoic acid, heptanoic acid, or octanoic acid with ethylene glycol. The reaction yield varies between 85 and 94%. The chemical composition of the prepared esters was examined using various spectroscopic methods (Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The thermal properties investigation by thermo gravimetric analysis (TGA) showed pronounced thermal stability of the prepared esters. The biodegradability was verified versus two bacterial isolates (B1, B2). The results showed that percentage of degradation of the lube oil was in the range of 34% to 84% after 3 days of incubation. Moreover, the rheological study revealed that the prepared esters exhibited Newtonian rheological behaviours. Viscosity examination displayed that the esters based on ethylene glycol, such as (A), had the highest VI: 179 values when compared to those based on higher glycols. Viscosity and viscosity index results showed slight increase as the number of carbon atoms in the acid chain increases. At last, most of the synthesized esters possessed pour points ≤ - 32 °C: ≤ - 40 except in case of using higher acids like heptanoic acid and octanoic acid in preparation the pour point increases to - 9 °C and - 15 °C.


Assuntos
Ésteres , Ácidos Heptanoicos , Ésteres/química , Caprilatos , Espectroscopia de Infravermelho com Transformada de Fourier , Polietilenoglicóis/química , Óleos de Plantas/química
3.
Chembiochem ; 25(6): e202300722, 2024 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-38235523

RESUMO

We report the first biocatalytic modification of sesquiterpene lactones (STLs) found in the chicory plants, specifically lactucin (Lc), 11ß,13-dihydrolactucin (DHLc), lactucopicrin (Lp), and 11ß,13-dihydrolactucopicrin (DHLp). The selective O-acylation of their primary alcohol group was carried out by the lipase B from Candida antarctica (CAL-B) using various aliphatic vinyl esters as acyl donors. Perillyl alcohol, a simpler monoterpenoid, served as a model to set up the desired O-acetylation reaction by comparing the use of acetic acid and vinyl acetate as acyl donors. Similar conditions were then applied to DHLc, where five novel ester chains were selectively introduced onto the primary alcohol group, with conversions going from >99 % (acetate and propionate) to 69 % (octanoate). The synthesis of the corresponding O-acetyl esters of Lc, Lp, and DHLp was also successfully achieved with near-quantitative conversion. Molecular docking simulations were then performed to elucidate the preferred enzyme-substrate binding modes in the acylation reactions with STLs, as well as to understand their interactions with crucial amino acid residues at the active site. Our methodology enables the selective O-acylation of the primary alcohol group in four different STLs, offering possibilities for synthesizing novel derivatives with significant potential applications in pharmaceuticals or as biocontrol agents.


Assuntos
Cichorium intybus , Sesquiterpenos , Ésteres/química , Simulação de Acoplamento Molecular , Acilação , Lactonas
4.
Food Res Int ; 173(Pt 1): 113289, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37803602

RESUMO

The intricate mechanisms of oil thermooxidation and their accurate prediction have long been hampered by the combinatory nature of propagation and termination reactions involving randomly generated radicals. To unravel this complexity, we suggest a two-scale mechanistic description that connects the chemical functions (scale 1) with the molecular carriers of these functions (scale 2). Our method underscores the importance of accounting for cross-reactions between radicals in order to fully comprehend the reactivities in blends. We rigorously tested and validated the proposed two-scale scheme on binary and ternary mixtures of fatty acid methyl esters (FAMEs), yielding three key insights: (1) The abstraction of labile protons hinges on the carrier, defying the conventional focus on hydroperoxyl radical types. (2) Termination reactions between radicals adhere to the geometric mean law, exhibiting symmetric collision ratios. (3) The decomposition of hydroperoxides emerges as a monomolecular process above 80 °C, challenging the established combinatorial paradigm. Applicable across a wide temperature range (80 °C to 200 °C), our findings unlock the production of blends with controlled thermooxidation stability, optimizing the use of vegetable oils across applications: food science, biofuels, and lubricants.


Assuntos
Ésteres , Óleos de Plantas , Ésteres/química , Óleos de Plantas/química , Ácidos Graxos/química , Relação Estrutura-Atividade , Biocombustíveis
5.
Environ Sci Pollut Res Int ; 30(12): 34481-34502, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36515877

RESUMO

Biodiesel is a biological renewable source produced from the conversion of triglycerides to alkyl esters. Palm oil is one of the most used lipid feedstocks for biodiesel production. It becomes necessary to optimize the transesterification reaction parameters to reduce the cost and enhance the quality of biodiesel. This study focuses on the use of homogenous sulfuric acid as a catalyst for the transesterification of palm fatty acids to methyl esters in a batch-scale reactor. A novel examination of transesterification reaction input parameters using the technique for order performance by similarity to ideal solution optimization technique and the effect of these parameters on yield, viscosity, and density of palm biodiesel using 3D surface graphs is investigated in this research. The present optimization approach is implemented to find out the optimum ranking of biodiesel production. From the experimental and numerical simulation, optimum results were observed at the catalyst concentration of 6% (w/w), reaction temperature of 70 °C, the reaction time of 120 min, and alcohol to oil molar ratio of 30:1 at which yield of 95.35%, viscosity of 5.0 cSt, and density of 880 kg/m3 of palm biodiesel were obtained. The different physicochemical properties of produced palm methyl esters are obtained within standards set by international authorities. Selected optimized process parameters can be used for commercial-scale biodiesel production.


Assuntos
Biocombustíveis , Óleos de Plantas , Óleo de Palmeira , Óleos de Plantas/química , Esterificação , Ésteres/química , Ácidos , Catálise , Etanol
6.
J Asian Nat Prod Res ; 25(7): 627-633, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36327879

RESUMO

Four new ferulic acid sucrose esters, ß-D-(1-O-acetyl-6-O-trans-feruloyl)fructofuranosyl-a-D-2',6'-O-diacetylglucopyranoside (1), ß-D-(1-O-acetyl-6-O-trans-feruloyl)fructofuranosyl-a-D-2',4'-O-diacetylglucopyranoside (2), ß-D-(6-O-trans-feruloyl)fructofuranosyl-a-D-2',4',6'-O-triacetylglucopyranoside (3), ß-D-(1-O-acetyl-6-O-trans-feruloyl)fructofuranosyl-a-D-4',6'-O-diacetylglucopyranoside (4), together with four known phenylpropanoids (5-8) were isolated from the rhizome of Sparganium stoloniferum (Graebn.) Buch.-Ham. ex Juz. Their structures were elucidated by chemical evidence and spectral analysis. Compounds 1-8 exhibited obvious inhibitory effects on ADP-induced platelet aggregation.


Assuntos
Medicamentos de Ervas Chinesas , Rizoma , Espectroscopia de Ressonância Magnética , Rizoma/química , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/química , Sacarose/análise , Sacarose/química , Ésteres/química
7.
J Agric Food Chem ; 70(43): 14073-14083, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36259733

RESUMO

Quercetin monoesters were prepared via a one-step enzymatic transesterification. The main acylation products were eight quercetin ester derivatives, respectively, consisting of varying acyl groups ranging from 2 to 18 carbon atoms (acetate, butyrate, caproate, caprylate, caprate, laurate, myristate, and stearate). The purified quercetin esters were structurally characterized by LC-ESI-ToF and NMR HSQC. Meanwhile, several classical chemical (DPPH, ABTS, FRAP, and Fe2+ chelation assays), food (ß-carotene bleaching assay), and biological (LDL and DNA oxidation assays) models were constructed to evaluate and systematically compare their antioxidant efficacy. O-Acylation increased the lipophilicity of quercetin derivatives, and lipophilicity increased with the increasing chain length of the acyl group. The dual effect of the acyl chain length on biasing quercetin monoesters' antioxidant efficacies has been summarized and verified. Overall, the results imply that the acylated quercetin have great potential as functional/health-beneficial ingredients for use in lipid-based matrices of cosmetics, supplements, and nutraceuticals.


Assuntos
Antioxidantes , Quercetina , Quercetina/química , Antioxidantes/química , Ácidos Graxos/química , Ésteres/química , Esterificação
8.
Food Res Int ; 160: 111760, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36076429

RESUMO

Polyphenol, though used as antioxidants in food industry, suffers from poor solubility issues in vegetable oil. Usually, its solubility would be enhanced through esterification. This work investigated the antioxidant activity and oxidative stability of caffeic acid (CA) and its derivative modified esters by molecular simulation and experiments. Density functional theory (DFT) and molecular dynamic analysis revealed the antioxidant mechanism of CA esters attributing to the comprehensive effects. The lower hydrogen dissociation energy (ΔG) of CA esters with catechol moiety caused the transformation of antioxidant into quinone via the double hydrogen atom transfer reaction. Particularly, the second reduced hydrogen dissociation energy was the keypoint. The strong non-bond energy and hydrogen bond allowed CA esters and oil molecules to interact more efficiently. Hence, the ester moieties enhanced the antioxidant activity with 4.5-6.5 % ΔG reduction compared to CA. Rancimat and DSC assays validated the theoretical predictions. This result shows that the antioxidant activity of CA and its esters could be predicted by this molecular simulation way, which may aid in designing of new polyphenol antioxidant structure.


Assuntos
Antioxidantes , Ésteres , Antioxidantes/química , Ácidos Cafeicos , Ésteres/química , Hidrogênio/farmacologia , Estresse Oxidativo , Polifenóis/farmacologia , Óleo de Girassol/farmacologia
9.
Biomacromolecules ; 23(10): 4203-4219, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36073031

RESUMO

Injectable, self-healing hydrogels with enhanced solubilization of hydrophobic drugs are urgently needed for antimicrobial intravaginal therapies. Here, we report the first hydrogel systems constructed of dynamic boronic esters cross-linking unimolecular micelles, which are a reservoir of antifungal hydrophobic drug molecules. The selective hydrophobization of hyperbranched polyglycidol with phenyl units in the core via ester or urethane bonds enabled the solubilization of clotrimazole, a water-insoluble drug of broad antifungal properties. The encapsulation efficiency of clotrimazole increases with the degree of the HbPGL core modification; however, the encapsulation is more favorable in the case of urethane derivatives. In addition, the rate of clotrimazole release was lower from HbPGL hydrophobized via urethane bonds than with ester linkages. In this work, we also revealed that the hydrophobization degree of HbPGL significantly influences the rheological properties of its hydrogels with poly(acrylamide-ran-2-acrylamidephenylboronic acid). The elastic strength of networks (GN) and the thermal stability of hydrogels increased along with the degree of HbPGL core hydrophobization. The degradation of the hydrogel constructed of the neat HbPGL was observed at approx. 40 °C, whereas the hydrogels constructed on HbPGL, where the monohydroxyl units were modified above 30 mol %, were stable above 50 °C. Moreover, the flow and self-healing ability of hydrogels were gradually decreased due to the reduced dynamics of macromolecules in the network as an effect of increased hydrophobicity. The changes in the rheological properties of hydrogels resulted from the engagement of phenyl units into the intermolecular hydrophobic interactions, which besides boronic esters constituted additional cross-links. This study demonstrates that the HbPGL core hydrophobized with phenyl units at 30 mol % degrees via urethane linkages is optimal in respect of the drug encapsulation efficiency and rheological properties including both self-healable and injectable behavior. This work is important because of a proper selection of a building component for the construction of a therapeutic hydrogel platform dedicated to the intravaginal delivery of hydrophobic drugs.


Assuntos
Ginecologia , Hidrogéis , Acrilamidas , Antifúngicos/farmacologia , Clotrimazol/farmacologia , Ésteres/química , Hidrogéis/química , Micelas , Uretana , Água
10.
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
11.
Bioresour Technol ; 363: 127990, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36130686

RESUMO

The removal of Diethyl hexyl phthalate (DEHP) and Dibutyl phthalate (DBP) is of great importance due to their potential adverse effects on the environment and human health. In this study, two bionanocomposites prepared by immobilization of Bacillus subtilis esterase by crosslinking to halloysite and supported in chitosan and alginate beads were studied and proposed as a green approach. The esterase immobilization was confirmed by physical-chemical characterization. Bionanocomposite using chitosan showed the best degradation levels in batch tests attaining complete degradation of DBP and around 90% of DEHP. To determine the operational stability and efficiency of the system, two fixed bed reactors filled with both bionanocomposites were carried out operating in continuous mode. Chitosan based bionanocomposite showed the best performance being able to completely remove DBP and more than 85% of DEHP at the different flowrates. These results proved the potential of these synthesized bionanocomposites to effectively remove Phthalic Acid Esters.


Assuntos
Quitosana , Dietilexilftalato , Ácidos Ftálicos , Humanos , Alginatos , Argila , Dibutilftalato/metabolismo , Esterases , Ésteres/química , Ácidos Ftálicos/metabolismo
12.
Food Chem ; 397: 133777, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-35914457

RESUMO

As a valuable medicinal and edible plant, Crocus sativus L. has had wide applications since ancient times. Herein, a comprehensive approach for characterization of constituents in saffron was established based on the combination of targeted and non-targeted strategies. A targeted UPLC-ESI/MSn strategy was applied for in-depth identification of crocins, and a non-targeted UPLC-ESI/MS2 approach characterized other components. This integration strategy was used to analyze ingredients in 21 batches of saffrons from 6 origins. Forty-seven crocins belonging to 8 types were identified including 32 new crocins. Among them, 6 new compounds with specific structures were reported for the first time, i.e. trans-6(G, 2G), trans-4(GT, g), trans-3(GT), cis-3(GT), methyl ester-trans-2(G) and methyl ester-cis-2(G). Besides, 91 non-crocin components were identified including 43 new compounds. Based on systematic investigation of crocins and non-crocins, we found that crocins were the critical components to distinguish saffrons from different origins, especially between domestic and foreign samples.


Assuntos
Crocus , Crocus/química , Ésteres/química , Extratos Vegetais/química
13.
J Oleo Sci ; 71(7): 975-984, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35691841

RESUMO

Tocopherols and phytosterols are generally considered to be nutritionally beneficial, and 3-Monochloropropane-1,2-diol esters (3-MCPD esters), glycidyl esters (GEs) and trans fatty acids (TFAs) are generally considered to be harmful. The high temperature deodorization step is when these harmful 3-MCPD esters, GEs and TFAs are generated. Knowing how deodorization conditions affect levels of these substances is essential for designing refining processes that will produce nutritious, high quality edible oils. This study analyzed the changes of these components of sunflower oil at different temperatures (210, 230, 250 and 270°C) and times (60, 80, 100 and 120 min) during deodorization. Our research found that during the whole deodorization process (including undeodorized sunflower oil), the contents of 3-MCPD esters, GEs and TFAs all progressively increased, from 0.47 to 11.18 mg/kg, 0.24 to 18.42 mg/kg and 0.062% to 0.698%, respectively. However, the deodorization process significantly decreased the levels of tocopherols (from 535.94 to 240.26 mg/kg) and phytosterols (from 2803.58 to 1864.34 mg/kg). Meanwhile, the retention ratios of total tocopherols and total phytosterols also decreased from 96.29% to 44.83% and 92.29% to 66.50%, respectively.


Assuntos
Fitosteróis , alfa-Cloridrina , Ésteres/química , Óleos de Plantas/química , Óleo de Girassol , Tocoferóis
14.
Chemosphere ; 305: 135335, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35724723

RESUMO

Membrane technology has been adopted as a prospective and promising alternative to the standard technology used for biodiesel production since the time when it had some limitations. During this research project, the inedible seed oil generating feedstock known as Saussurea heteromalla was put through a biodiesel production process that utilized membrane technology with an effort to increase the yield of methyl ester. The transesterification process was mediated by zirconium oxide nanoparticles that were generated using an aqueous extract of Portulaca oleracea leaf. With an oil to methanol ratio of 1:9, a catalyst concentration of 0.88 (wt. %), temperature of 87 °C, and reaction time of 180 min, the highest possible biodiesel yield of 93% was achieved. The findings of the catalyst characterization demonstrated the purity of the zirconium oxide nano particles and their nanoscale nature with average particle size of 31 nm. Using gas chromatography and mass spectrometry (GC/MS), an examination of biodiesel revealed the presence of four different peaks of methyl esters. Using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance, we were able to verify that the production of methyl esters in the biodiesel sample was successful (NMR). Zerconium oxide nanoparticles were found reusable up to five consecutive cycles of transesterification. The fuel-related properties of methyl ester have been determined and are in line with the requirements of the international standards ASTM D-6571 and EN 14214. In the course of our ongoing research, we made use of membrane technology, which led to the production of biodiesel from the seed oil of Saussurea heteromalla that was better for the environment, more cost effective, and produced in greater quantities.


Assuntos
Biocombustíveis , Saussurea , Biocombustíveis/análise , Catálise , Esterificação , Ésteres/química , Óleos de Plantas/química
15.
Food Res Int ; 157: 111217, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35761539

RESUMO

Surfactants are used in confectionery production to control the viscosity and yield value of molten chocolate. To develop a deeper understanding of the structure-function relationship of surfactants in food-related particle suspensions, the apparent viscosity, yield value, sedimentation, and particle interactions of 10 wt% confectioner's sugar-in-canola oil suspensions were investigated in the presence of up to 1 wt% commercial soy lecithin, polyglycerol polyricinoleate (PGPR), citric acid esters of monoacylglycerols (CITREM) or ammonium phosphatides (AMP). Atomic force microscopy (AFM) was used to measure attractive forces at the nano-Newton scale between a sugar substrate and a sugar crystal-functionalized AFM cantilever in an oil environment. For all but PGPR, addition of surfactant reduced the adhesion force between sugar surfaces up to a critical concentration above which the force increased, implying the presence of additional interactions. This critical concentration was assumed to be when monolayer coverage of the sugar surfaces by surfactant occurred (0.05 wt% for lecithin, 0.10 wt% for CITREM and AMP). No critical concentration was found for PGPR, with its greatest effect for each analysis occurring at the highest concentrations tested (0.60 and 1.00 wt%). The significance of these interactions on macroscopic phenomena such as apparent viscosity and sedimentation was also assessed. Like with the AFM data, there was an optimal concentration of added surfactant above which viscosity increased. Sedimentation rate greatly decreased with addition of PGPR while being only slightly affected by addition of lecithin, CITREM and AMP. An argument regarding their efficacy was made based on the relative sizes of the polar headgroup and nonpolar tail groups of the molecules, which contributed to how they adsorbed to the sugar surface. Overall, these results suggested that surfactant properties such as molecular weight and head group properties played an important role in modifying the interactions between sugar crystals in an oil-continuous environment.


Assuntos
Lecitinas , Tensoativos , Ésteres/química , Lecitinas/química , Açúcares , Tensoativos/química , Suspensões
16.
Angew Chem Int Ed Engl ; 61(35): e202205816, 2022 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-35639345

RESUMO

The synthesis of molecules bearing two or more contiguous, quaternary stereocenters is challenging, owing to the difficulty in controlling stereochemistry whilst simultaneously constructing a sterically congested motif. Herein, we report the electrophile-induced ring contractive 1,2-metallate rearrangement of 6-membered cyclic alkenyl boronate complexes for the synthesis of cyclopentyl boronic esters bearing two contiguous, fully substituted stereocenters with high levels of stereocontrol. Remarkably, simple variation of the reaction solvent enabled their diastereodivergent construction with facile access to complementary diastereomeric pairs. The utility of our methodology is demonstrated in the asymmetric total synthesis of (+)-herbertene-1,14-diol.


Assuntos
Boro , Ésteres , Ésteres/química , Estereoisomerismo
17.
J Agric Food Chem ; 70(17): 5369-5376, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35445595

RESUMO

Branched fatty acid ester of hydroxy fatty acid (FAHFA) is a class of natural lipid with important biological functions. In this study, we first profiled natural-origin FAHFAs in different teas using the chemical labeling-assisted liquid chromatography-mass spectrometry method. Consequently, we observed rich molecular diversity of FAHFAs with multiple regioisomers in teas. Additionally, the FAHFA contents had a positive relationship with the tea fermentation degree and a negative relationship with homologous fatty acids. Moreover, the highly accumulated FAHFAs (e.g., 3-MAHMA) in some postfermented teas (e.g., Fu brick tea) were also basically interpreted with regiospecificity of FAHFAs in both teas and fungus. This study revealed that tea is a rich natural source of FAHFAs, and some abundant FAHFAs might be the functional molecules accounting for the antidiabetic function of teas.


Assuntos
Ésteres , Ácidos Graxos , Cromatografia Líquida/métodos , Ésteres/química , Ácidos Graxos/química , Espectrometria de Massas , Chá
18.
Food Chem ; 387: 132882, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35398685

RESUMO

DHA is most often used in supplements either in its triacylglycerol or ethyl ester form. Currently, there is only little published data on the differences in the oxidative stability and α-tocopherol response between the two lipid structures, as well as on the oxidation patterns of pure DHA. This study investigated the oxidative stability, α-tocopherol response and oxidation pattern of DHA incorporated in triacylglycerols and as ethyl esters with an untargeted approach after oxidation at 50 °C in the dark. Liquid and gas chromatographic methods with mass spectrometric detection and nuclear magnetic resonance spectroscopy were applied. DHA was more stable in triacylglycerols than as ethyl esters without α-tocopherol addition. With α-tocopherol added the opposite was observed. The oxidation products formed during triacylglycerol and ethyl ester oil oxidation were mostly similar, but also some structure-related differences were detected in both volatile and non-volatile oxidation products.


Assuntos
Ácidos Docosa-Hexaenoicos , Ésteres , Ácidos Docosa-Hexaenoicos/química , Ésteres/química , Cromatografia Gasosa-Espectrometria de Massas , Oxirredução , Estresse Oxidativo , Triglicerídeos/química , alfa-Tocoferol
19.
Molecules ; 27(3)2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35163960

RESUMO

The calyxes and fruits of Physalis alkekengi L. var. franchetii (Mast.) Makino (P. alkekengi), a medicinal and edible plant, are frequently used as heat-clearing and detoxifying agents in thousands of Chinese medicine prescriptions. For thousands of years in China, they have been widely used in clinical practice to treat throat disease, hepatitis, and bacillary dysentery. This systematic review summarizes their structural analysis, quality control, pharmacology, and pharmacokinetics. Furthermore, the possible development trends and perspectives for future research studies on this medicinal plant are discussed. Relevant information on the calyxes and fruits of P. alkekengi was collected from electronic databases, Chinese herbal classics, and Chinese Pharmacopoeia. Moreover, information was collected from ancient documents in China. The components isolated and identified in P. alkekengi include steroids, flavonoids, phenylpropanoids, alkaloids, nucleosides, terpenoids, megastigmane, aliphatic derivatives, organic acids, coumarins, and sucrose esters. Steroids, particularly physalins and flavonoids, are the major characteristic and bioactive ingredients in P. alkekengi. According to the literature, physalins are synthesized by the mevalonate and 2-C-methyl-d-erythritol-4-phosphate pathways, and flavonoids are synthesized by the phenylpropanoid pathway. Since the chemical components and pharmacological effects of P. alkekengi are complex and varied, there are different standards for the evaluation of its quality and efficacy. In most cases, the analysis was performed using high-performance liquid chromatography coupled with ultraviolet detection. A pharmacological study showed that the crude extracts and isolated compounds from P. alkekengi had extensive in vitro and in vivo biological activities (e.g., anti-inflammatory, anti-tumor, immunosuppressive, antibacterial, anti-leishmanial, anti-asthmatic, anti-diabetic, anti-oxidative, anti-malarial, anti-Alzheimer's disease, and vasodilatory). Moreover, the relevant anti-inflammatory and anti-tumor mechanisms were elucidated. The reported activities indicate the great pharmacological potential of P. alkekengi. Similarly, studies on the pharmacokinetics of specific compounds will also contribute to the progress of clinical research in this setting.


Assuntos
Produtos Biológicos/análise , Physalis/enzimologia , Physalis/metabolismo , Produtos Biológicos/farmacologia , China , Cromatografia Líquida de Alta Pressão/métodos , Ésteres/química , Flavonoides , Flores/efeitos dos fármacos , Frutas/efeitos dos fármacos , Physalis/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Sacarose/química
20.
J Oleo Sci ; 71(1): 51-55, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-34880149

RESUMO

Vitamin E (VitE) production from crude palm oil (CPO) has been extensively studied and industrially conducted. VitE in CPO is in the range of 600 to 1,000 ppm, and is usually produced from one of the main by-products of edible palm oil production, namely palm fatty acid distillate (PFAD). PFAD contains 4,000 to 5,500 ppm of VitE, and is produced from deodorization process of palm oil purification. This paper presents an innovative process of VitE concentrate production from CPO. A scrubber was designed and installed between the deodorizer and conventional PFAD scrubber. The main objective of this new scrubber was a recovery of glycerides from PFAD. This new scrubber is operated at 150 to 160℃. The scrubbed oil is named as Scrubbed Palm Fatty Acid Distillate (S-PFAD). This simple and efficient modified process can retrieve glycerides as S-PFAD at 0.3% recovery and it enhances VitE concentration in S-PFAD to the range of 28,000 to 32,000 ppm, which is the highest concentration of VitE that has ever been produced in the palm oil production. Fatty acids and glycerides in S-PFAD were esterified and transesterified to methyl esters. The methyl esters were evaporated from S-PFAD, and S-PFAD residue oil contained 24.7% VitE.


Assuntos
Manipulação de Alimentos/métodos , Óleo de Palmeira/química , Vitamina E/isolamento & purificação , Esterificação , Ésteres/química , Glicerídeos/isolamento & purificação , Temperatura Alta , Óleo de Palmeira/análise , Vitamina E/análise
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