Glycerol Tripalmitate Research Articles

Enhancing the Thermostability and Catalytic Activity of the Lipase from Rhizopus oryzae via Introducing N-Glycosylation.

Lipase from Rhizopus oryzae (ROL) exhibits remarkable sn-1,3 stereoselectivity and catalytic activity, but its poor thermostability limits its applications in the production of 1,3-dioleoyl-2-palmitoyl glycerol (OPO, a high-quality substitute for human milk fat). In this work, a semirational method was proposed to engineer the thermostability and catalytic activity of 4M (ROL mutant in our previous study). First, a computer-aided design is performed using 4M as a template, and N-glycosylation mutants are then recombinantly expressed and screened in Pichia pastoris, the optimal mutant N227 exhibited a half-life of 298.8 h at 45 °C, which is 7.23-folds longer than that of 4M. Its catalytic activity also reached 1043.80 ± 61.98 U/mg, representing a 29.2% increase compared to 4M (808.02 ± 47.02 U/mg). Molecular dynamics simulations of N227 suggested that the introduction of glycan enhanced the protein rigidity, while the strong hydrogen bonds formed between the glycan and the protein stabilized the lipase structure, thereby improving its thermostability. The acidolysis reaction between oleic acid (OA) and glycerol tripalmitate (PPP) was successfully carried out using immobilized N227, achieving a molar conversion rate of 90.2% for PPP. This engineering strategy guides the modification of lipases, while the glycomutants obtained in this study have potential applications in the biosynthesis of OPO.

Physicochemical and In Vitro Digestion Properties of Curcumin-Loaded Solid Lipid Nanoparticles with Different Solid Lipids and Emulsifiers.

Curcumin-loaded solid lipid nanoparticles (Cur-SLN) were prepared using medium- and long chain diacylglycerol (MLCD) or glycerol tripalmitate (TP) as lipid matrix and three kinds of surfactants including Tween 20 (T20), quillaja saponin (SQ) and rhamnolipid (Rha). The MLCD-based SLNs had a smaller size and lower surface charge than TP-SLNs with a Cur encapsulation efficiency of 87.54-95.32% and the Rha-based SLNs exhibited a small size but low stability to pH decreases and ionic strength. Thermal analysis and X-ray diffraction results confirmed that the SLNs with different lipid cores showed varying structures, melting and crystallization profiles. The emulsifiers slightly impacted the crystal polymorphism of MLCD-SLNs but largely influenced that of TP-SLNs. Meanwhile, the polymorphism transition was less significant for MLCD-SLNs, which accounted for the better stabilization of particle size and higher encapsulation efficiency of MLCD-SLNs during storage. In vitro studies showed that emulsifier formulation greatly impacted on the Cur bioavailability, whereby T20-SLNs showed much higher digestibility and bioavailability than that of SQ- and Rha-SLNs possibly due to the difference in the interfacial composition. Mathematical modeling analysis of the membrane release further confirmed that Cur was mainly released from the intestinal phase and T20-SLNs showed a faster release rate compared with other formulations. This work contributes to a better understanding of the performance of MLCD in lipophilic compound-loaded SLNs and has important implications for the rational design of lipid nanocarriers and in instructing their application in functional food products.

Fabrication of immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoylglycerol

This study aims to fabricate immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) through acidolysis of glycerol tripalmitate (PPP). Twelve (three types) supports and five lipases were studied carefully. Among them, the immobilized Thermomyces lanuginosa lipase (TLL) samples exhibited overall better performance than that of other immobilized lipases. Particularly, organic groups functionalized SBA-15 (R-SBA-15) supported TLL (TLL@R-SBA-15) samples gave PPP conversion from 97.70 to 99.00 % and OPO content from 59.52 to 64.73 %. After optimization, PPP conversion up to 99.07 %, OPO content 73.15 % and sn-2 palmitic acid content 90.09 % were obtained with TLL@C18H37-SBA-15 as catalyst. Moreover, TLL@C18H37-SBA-15 exhibited better acidolysis performance from 50 °C than that from 60 to 80 °C, which helped inhibit acyl migration. In addition, after 5 cycles of reuse, TLL@C18H37-SBA-15 retained 81.04 % (based on OPO content) and 98.88 % (based on sn-2 palmitic acid content) of its initial activity, indicating it had an attractive prospect in future applications.

Digestive behavior of unemulsified triglycerides with different chain lengths: In vitro dynamic and static simulated digestion models

Glyceryl tributyrate (GTB), glyceryl tridodecanoate (GTD) and glycerol tripalmitate (GTP) are typically short, medium and long-chain fatty acid glycerides, respectively. Their digestion behaviors play decisive roles in their health benefits. In this study, the digestion behaviors of unemulsified GTB, GTD and GTP were compared in the dynamic simulation digestion model (artificial gastric digestive system and semi-dynamic intestinal digestive system) and static simulation digestion model. In these two models, the digestibility is GTB > GTD > GTP. In the gastric phase, 4.5%–24.5% of triglycerides were hydrolyzed, and this phenomenon was more obvious in the dynamic model. In addition, the transition of digestive behaviors from the stomach to the intestine was smoother in the dynamic model. The particle size of GTB is usually smaller than those of GTD and GTP, and this difference was weakened in the dynamic model. The high melting point of GTD and GTP also hindered their binding with digestive enzymes in digestion. Our research filled the gaps in the study of the digestion behaviors of unemulsified triglycerides with different chain lengths in different models.

Characterization of a novel sn1,3 lipase from Ricinus communis L. suitable for production of oleic acid-palmitic acid-glycerol oleate

The hydrolysis properties of lipase in castor was evaluated using two different substrate forms (tripalmitic glycerides and trioleic glycerides) to catalyze the reaction under different operational conditions. RcLipase was obtained from castor seeds and results show that RcLipase is a conservative serine lipase with a conserved catalytic center (SDH) and a conserved pentapeptide (GXSXG). This enzyme exhibited the greatest activity and tolerance to chloroform and toluene when it was expressed in Pichia pastoris GS115 at 40 ℃ and pH 8.0. Zn and Cu ions exerted obvious inhibitory effects on the enzyme, and displayed good hydrolytic activity for long-chain natural and synthetic lipids. HPLC analysis showed that this enzyme has 1,3 regioselectivity when glycerol tripalmitate and oleic acid are used as substrates. The fatty acid composition in the reaction product was 21.3% oleic acid and 79.1% sn-2 palmitic acid.

Brain Targeting of Duloxetine HCL via Intranasal Delivery of Loaded Cubosomal Gel: In vitro Characterization, ex vivo Permeation, and in vivo Biodistribution Studies.

PurposeDuloxetine (DLX) is dual serotonin and norepinephrine reuptake inhibitor suffering from limited bioavailability (≈ 40%) due to extensive hepatic metabolism. This work aims to formulate and evaluate DLX intranasal thermoreversible cubosomal gels to enhance its bioavailability and ensure efficient brain targeting.Materials and MethodsCubo-gels were prepared by 33 central composite design with three independent factors, lipid ratio (glycerol monooleate: glycerol tripalmitate), Pluronic F127%, and Pluronic F68%. The prepared formulations were evaluated for their particle size (PS), gelling temperature (GT), entrapment efficiency (EE%), and in vitro release. The cubo-gel with the highest desirability (0.88) was chosen as the optimized formulation. DLX cubo-gel was evaluated using differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. Cytotoxicity study, ex vivo permeation study and in vivo bio-distribution study were conducted to evaluate the safety and efficacy of brain targeting.ResultsThe optimum cubo-gel was composed of 3.76 lipid ratio, 20% w/v PF127, and 5% w/v PF68. It had PS of 265.13 ± 9.85 nm, GT of 32 ± 0.05°C, EE% of 98.13 ± 0.50%, and showed controlled release behavior where 33% DLX was released within 6 hrs. The plain in situ cubo-gel had a significantly higher IC50 compared to DLX solution and DLX-loaded in situ cubo-gel. The ex vivo permeation study showed 1.27 enhancement in the drug permeation from DLX in situ cubo-gel. According to the in vivo bio-distribution study in plasma and brain, the intranasal DLX in situ cubo-gel showed a 1.96 fold improvement in brain bioavailability compared to the intranasal solution. Its BTE% and DTP% were 137.77 and 10.5, respectively, indicating efficient brain targeting after intranasal administration.ConclusionAccordingly, intranasal DLX in situ cubo-gel can be considered as an innovative nano-carrier delivery system for bioavailability enhancement and efficient brain targeting of DLX to maximize its effect.

Well-defined core-shell nanostructural block copolymer supported recyclable Bronsted acidic ionic liquid catalyst for the synthesis of biodiesel

A series of Bronsted acidic ionic liquid catalysts was synthesized by anchoring 1-(3-sulfopropyl)pyridinium trifluoromethanesulfonate onto the stable core-shell micelles, which were formed by cross-linking various chain length ratios PS-b-P4VP in toluene with 1,4-dibromobutane. These catalysts display excellent catalytic activity in the esterification or transesterification of palmitic acid or glycerol tripalmitate with methanol or ethanol to synthesize the biodiesel (yield > 99%) in the presence of 4 mol% catalyst loading. Furthermore, the biodiesel yield was maintained about 90% even with a water content of 10 wt% corresponding to the total weight of reaction system. More importantly, these supported catalysts with core-shell structure could be recycled for 5–6 times (5 cycles: yield 89.3%, 6 cycles: yield 84%) only by simple centrifugation without appreciating activity decrease.

Improved antileishmanial activity and cytotoxicity of a novel nanotherapy for N-iodomethyl-N,N-dimethyl-N-(6,6-diphenylhex-5-en-1-yl)ammonium iodide

The N-iodomethyl-N, N-Dimethyl-N-(6,6-diphenylhex-5-en-1-yl) ammonium iodide (C6I) is a new chemical entity (NCE) with demonstrated in vitro and in vivo antileishmanial activity. As many others NCE, C6I is poorly water soluble (Class II of the Biopharmaceutical Classification System), thus its oral administration is potentially compromised. To overcome the issue, nanotechnology is a real and useful tool. Moreover, nanotechnology can improve C6I internalization by macrophages, the drug targets, therefore increasing its antileishmanial activity.The present work aimed to develop a potential suitable oral nanodrug delivery system for C6I to improve its antileishmanial activity. For this purpose, polymeric and solid lipid nanoparticles were developed. Polylactic-co-glycolic acid polyester (PLGA) were prepared by nanoprecipitation while solid lipid nanoparticles made of glycerol tripalmitate (Trp) and glyceryl tristearate (Trs) were obtained by emulsion–solvent evaporation method. Physicochemical characterization of all formulations was performed, as well as stability studies. A lyophilization procedure was also established. Biological activity was evaluated by antileishmanial activity and cytotoxicity in vitro assays.Five types of commercial PLGA to encapsulate C6I were tested. The best results were obtained using PLGA 752S and d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS), the water-soluble form of vitamin E. Particles around 220 nm in diameter and encapsulation efficiency (EE) up to 60% were obtained. Solid lipid nanoparticles based on Trs and Trp lipids were also in the nanoscale showing a low polydispersity index and EE% >60%. Both types of nanoformulations, polymeric and lipidic, thd C6I cytotoxicity in human and hamster macrophages cell cultures. In vitro assays with PLGA loaded-C6I showed a noticeable improved antileishmanial activity on intracellular amastigotes of L. (V.) panamensis, with the following EC50 values: PLGA «< Trs-SLN « free C6I < Trp-SLN. In conclusion, PLGA nanoformulation could be a suitable candidate for preclinical evaluation in animal model.

A rapid and non-destructive method for quantifying biomolecules in Spirulina platensis via Fourier transform infrared – Attenuated total reflectance spectroscopy

This study aimed to develop a method to rapidly quantify biomolecules in Spirulina platensis. Fourier transform infrared (FTIR) spectra of Spirulina cells were modeled from the individual spectra of glucose, bovine serum albumin and glycerol tripalmitate standards by iterative spectral subtraction and addition methods in accordance with the Beer-Lambert's law. Multipoint regression and partial least squares (PLS) regression techniques were used to create separate regression models for protein, carbohydrate and lipid analysis. These models were made within the characteristic wavenumbers of target biomolecules. The predictive power of the regression models was characterized by coefficient of determination (R2), root mean square error of prediction (RMSEP), residual predicted deviation (RPD), and relative error. Results from regression models were also compared to conventional biochemical methods using appropriate mean comparison technique. Results show that PLS models for protein, carbohydrate, and lipids have higher R2 and RPD and lower RMSEP and relative error than multipoint regression. Furthermore, algal composition predicted by PLS-regression are statistically similar to the composition determined via conventional methods. Both regression methods have poor predictive power for lipid content as illustrated by RPD < 1.5 and relative error ≥ 70%. This may be due to indistinct absorbance of the CO ester characteristic band owing to overlaps with the tail of amide I band and due to low lipid content of Spirulina sp. Nevertheless, FTIR spectroscopy coupled with PLS-regression technique proves to be a fast, non-destructive and reliable method in quantifying biomolecules in Spirulina.

Determination of the Crystallization Behavior of Lipids by Temperature Modulated Optical Refractometry

This study was conducted to examine if the new temperature modulated optical refractometry (TMOR) method is applicable to study the phase behavior of alkyl-based components. n-Hexadecane, palmitic acid, and glycerol tripalmitate were used as model components. TMOR was benchmarked against differential scanning calorimetry (DSC) and polarized light microscopy (PLM). For all substances, a good agreement of the DSC data with TMOR was found. For n-hexadecane, a difference of 2.2 °C for the crystallization and 2.6 °C for the melting temperature was found. Considering palmitic acid, the crystallization temperature differed by 3.3 °C while the melting varied by 2.8 °C. The crystallization temperature of tripalmitate identified by TMOR was 2.7 °C higher, and the melting temperature 2.3 °C was lower compared to the DSC. The crystallization temperature for TMOR was always higher, and the melting temperature was always lower if related to DSC. This leads to the conclusion that TMOR is more accurate and direct. In addition, the transition peaks identified by TMOR were narrower compared to the DSC peaks. This is due to slower heating and cooling rates leading to a smaller temperature range of phase transition and less thermal lag. The study showed that TMOR is an appropriate method to determine the phase transition temperatures for the three examined substances. The results were comparable to the DSC data in both melting and crystallization behavior. Since the accuracy of TMOR is better at lower heating and cooling rates, it could be a reasonable extension of the well-known DSC method in the studies of melting and crystallization.

Hydrophobic fractal surface from glycerol tripalmitate and the effects on C6 glioma cell growth

To provide a biomimic environment for glial cell culture, glycerol tripalmitate (PPP) has been used as a raw material to prepare fractal surfaces with different degrees of hydrophobicity. The spontaneous formation of the hydrophobic fractal surfaces was monitored by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The surface morphologies were observed by a scanning electron microscope (SEM), and then the fractal dimension (FD) values of the surfaces were determined with the box-counting method. C6 glioma cells were cultured and compared on different hydrophobic PPP surfaces and poly-L-lysine (PLL)-coated surface. The cell numbers as a function of incubation time on different surfaces during the cell proliferation process were measured, and the cell morphologies were observed under a fluorescence microscope. Influences of hydrophobic fractal surfaces on the cell number and morphology were analyzed. The experimental results show that the cell proliferation rates decrease while the cell morphology complexities increase with the growth of the fractal dimensions of the PPP surfaces.

Temperature- and Pressure-Dependent Densities, Self-Diffusion Coefficients, and Phase Behavior of Monoacid Saturated Triacylglycerides: Toward Molecular-Level Insights into Processing

Using molecular-dynamics (MD) simulations the densities and self-diffusion coefficients of a range of liquid monoacid triacylglycerides (TAGs) have been studied as a function of temperature and, for the first time, pressure. While offset by their ambient properties, the response of the TAGs to temperature and pressure is qualitatively similar. Application of pressure was found to significantly increase densities and reduce diffusion of the TAG molecules, suggesting that it may have as much a role in processing and crystallizing TAGs as supercooling does. A solution of glycerol tripalmitate and glycerol trihexanoate was also studied, showing that application of pressure should lead to a significant decrease in the saturation point of the solution, which is an important consideration for processing TAGs. Different solid/liquid interfaces of glycerol tripalmitate have also been investigated. Although crystal growth could not be observed, dissolution of one interface was seen in the MD simulations. The results suggest that over moderate distances the melting of TAGs may be cooperative in nature, rather than involving dissolution of individual TAG molecules.

Novel Iso-branched Ether Lipids as Specific Markers of Developmental Sporulation in the Myxobacterium Myxococcus xanthus

Iso-fatty acids (FAs) are the dominant FA family in all myxobacteria analyzed. Furthermore, it was postulated that iso-FAs or compounds derived thereof are involved in fruiting body formation in Myxococcus xanthus, since mutants with a reduced level of iso-FA due to a reduced level of the precursor isovaleryl-CoA, are delayed in aggregation and produce only few myxospores. To elucidate the function of iso-FAs and their corresponding lipids we have analyzed the developmental phenotype of mutants having different levels of iso-FAs resulting in a clear correlation between the amount of iso-FAs and the delay of aggregation and reduction in spore yield. Addition of either isovalerate or 13-methyltetradecanoic acid resulted in restoration of the wild-type FA profile and normal development. Detailed analysis of the fatty acid (FA) profile during fruiting body formation in Myxococcus xanthus wild-type revealed the specific accumulation of 13-methyltetradecanal and 1-O-13-methyltetradecylglycerol which were produced specifically in the myxospores and which are derived from 1-O-(13-methyl-1-Z-tetradecenyl)-2-O-(13-methyltetradecanoyl)-glycero-3-phosphatidylethanolamine (VEPE) and 1,2-di-(13-methyltetradecanoyl)-3-(13-methyltetradecyl)glycerol (TG-1), respectively. The structures of these unusual ether lipids have been determined by spectrometric methods and synthesis (for TG-1). Analysis of several mutants blocked at different stages of development indicated that the biosynthesis of TG-1 is developmentally regulated and that VEPE might be an intermediate in the TG-1 biosynthesis. Finally, addition of TG-1 to mutants blocked in the biosynthesis of isovaleryl-CoA could restore aggregation and sporulation emphasizing the important role of iso-branched lipids for myxobacterial development.

Lipidic implants for controlled release of bioactive insulin: Effects on cartilage engineered in vitro

Controlled release systems for growth factors and morphogens are potentially powerful tools for the engineering or the treatment of living tissues. However, due to possible instabilities of the protein during manufacture, storage, and release, in the development of new release systems it is paramount to investigate into the maintenance of bioactivity of the protein. Within this study, recently developed protein releasing lipid matrix cylinders of 2 mm diameter and 2 mm height made from glycerol tripalmitate were manufactured in a compression process without further additives. Insulin in different concentrations (0.2%, 1%, and 2%) served as model protein. The bioactivity of the protein released from the matrices was investigated in a long-term cartilage engineering culture for up to four weeks; additionally, the release profiles were determined using ELISA. Insulin released from the matrices increased the wet weights of the cartilaginous cell-polymer constructs (up to 3.2-fold), the amount of GAG and collagen in the constructs (up to 2.4-fold and 3.2-fold, respectively) and the GAG and collagen content per cell (1.8-fold and 2.5-fold, respectively), compared to the control. The dose-dependent effects on tissue development correlated well with release profiles from the matrices with different insulin loading. In conclusion, the lipid matrices, preserving the bioactivity of incorporated and released protein, are suggested as a suitable carrier system for use in tissue engineering or for the localized treatment of tissues with highly potent protein drugs such as used in the therapy of brain cancer or neurodegenerative CNS diseases.

Study on Autoxidation Kinetics of Fats by Differential Scanning Calorimetry. 1. Saturated C12−C18 Fatty Acids and Their Esters

Differential scanning calorimetry was used to follow the oxidation course of the saturated fatty acids lauric, myristic, palmitic, and stearic and their ethyl esters and, additionally, glycerol tripalmitate and tristearate. Assessment of the oxidative stability of these fat components was performed at 90−300 °C without any solvents and in the absence of free-radical initiators. The calculated overall activation energies were in the range 106.0−123.3 kJ/mol. Obtained overall rates constants of autoxidation (k) were not dependent on the length of the carbon chain, and k's for acids were greater than those for esters and triglycerides. The applicability of thermoanalytical methods to determine the kinetic parameters of lipid oxidation was verified by comparison with values of activation energies and rate constants of oxidation determined by GC.

Effects of glycerol tripalmitate and glycerol trioleate on intestinal absorption of glycerol tristearate

The goal of the present study was to determine 1) whether the poor digestion and absorption of glycerol tristearate (TS) that we observed previously is due to amount fed and 2) whether the digestion, absorption, and lymphatic transport of TS is affected by the presence of either a saturated fat [glycerol tripalmitate (TP)] or a monounsaturated fat [glycerol trioleate (TO)]. Three groups of intestinal lymph fistula rats were used. Group A was fed a lipid emulsion containing 12.5 mumol of TS (labeled as [glyceryl-1,3-14C]tristerate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline per hour for 8 h. Group B rats were fed the same emulsion as group A, but with 12.5 mumols of TO added. Group C rats had 12.5 mumols of TP instead of TO added to the group A emulsion. The lymphatic radioactivity and triglyceride outputs were significantly lower in group A, with group C next and group B having the highest outputs. Significantly more TS remained in the lumen of the group A rats compared with groups B and C. The majority of the radioactivity in the lumen was still in the TS form in all three groups, indicating poor lipolysis. However, once the fatty acid and monoglyceride were absorbed, the reesterification process was similar in all three groups. When we studied the ability of the three groups of animals to transport the absorbed lipid into lymph (lymph transport index), both groups B and C were significantly better than group A rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial purification and some properties of the lipase present in oil palm (Elaeis guineensis) mesocarp

AbstractThe fatty layer obtained by centrifuging a homogenate of oil palm fruit mesocarp contains an active lipase. The lipase which was partially purified using a combination of ammonium sulphate fractionation, ion exchange and gel filtration chromatography, indicated an optimum activity at pH 4.5 and a temperature of 30°C. The enzyme exhibited good activity towards its natural substrate, palm oil as well as glycerol trioleate and glycerol tripalmitate. It also showed a linear reaction rate for the first 20 min of incubation. Sodium cyanide, resorcinol, cholesterol, lecithin and glycylglycine strongly inhibited its activity while phenol, L‐cysteine and EDTA enhanced its activity. It is suggested that the lipase is associated with the membrane of the oil droplets.

The association of saturated and unsaturated triglycerides and oleic acid with wheat flour components during dough making

AbstractThe association of lipids with other flour components after dough making has been examined by aqueous fractionation of flour prior to the extraction of lipids. Glycerol tripalmitate has been shown to be associated with acetic‐acid‐insoluble protein while glycerol trioleate associates with the glutenin of acetic‐acid‐soluble protein. Oleic acid divides fairly evenly between these fractions. Changes in lipid and protein distribution in some fractions are associated with the addition of oleic acid to the dough. Some of these changes are at least partially reversed by increasing the triglyceride content of the dough.

Gross Energy Values of Oils from High and Low Erucic Acid Rapeseed Oils and of Rapeseed Gums

Oils from seven rapeseed cultivars ranging in erucic acids levels from 0–59%; a commercial low erucic acid, refined oil; purified samples of linoleic, linolenic, caprylic, arachidonic and erucic acids; commercial and refined lecithin, egg lecithin and acetone-extracted rapeseed lecithin from low erucic acid rapeseed oil and glycerol tripalmitate, were analyzed for fatty acids by gas liquid chromatography and for gross energy (heat of combustion) by adiabatic bomb calorimetry. The oils ranged from 39.4–40.6kJ/g (9.4–9.7 Kcal/g), reflecting the higher values of the C:22 component for the high erucic acid cultivars. Rapeseed gums (oil-free) contained 30.2kJ/g (7.22 Kcal/g). The gross energy value of raw gums, available for digestion and potentially effective as a dietary energy source, was estimated to be between 28.9–30.5kJ/g (6.9 and 7.3 Kcal/g) depending mainly on the prevailing content of rapeseed oil.

Lipid Synthesis and Reproduction in the Polar Shrimp Chorismus antarcticus

Lipid Synthesis and Reproduction in the Polar Shrimp Chorismus antarcticus