Glycerol Ester Research Articles

Solvent‐free synthesis of medium chain triacylglycerols by esterification of capric, caprylic acids with 1, 3‐specific and non‐specific lipases

AbstractMedium chain triacylglycerols (MCTs) are used as a functional oil in various food and pharmaceutical formulations because of their numerous health benefits and physical properties. Enzymatic esterification of glycerol with caprylic (C8:0) and capric acids (C10:0) in a molar ratio of 1:3.5 [50% (C8:0) and 50% (C10:0)] was carried out for the solvent free synthesis of MCTs using 5% (w/w) 1,3 specific lipase, Lipozyme RM IM and non‐specific lipase, Novozym 435 in the presence of molecular sieves (10%) and low pressure conditions (50 and 150 mbar) at 50°C. Novozym 435 was more effective in the esterification reaction under 50 mbar reduced pressure, achieving ~54.74% triacylglycerol formation in 6 h, compared to Lipozyme RMIM, which achieved ~31.25% under the same conditions. Further reactions with Novozym 435 for 24 h showed that the maximum formation of MCTs occurred at 20 h (86.46 ± 3%), after which the reaction reached equilibrium. When 50 mbar was used, the formation of triacylglycerols enhanced 13 times compared with the results obtained at atmospheric pressure condition. Chemical characterization of the final MCTs confirmed the formation of four triacylglycerol species (TAG (8:0/8:0/8:0), TAG (8:0/8:0/10:0), TAG (8:0/10:0/10:0), and TAG (10:0/10:0/10:0) with LC–MS and NMR analysis. The melting and crystallization points of the synthesized oil was found to be −3.47°C and −23.48°C, respectively. Our findings contribute to developing a green process for synthesizing MCTs using two different fatty acids. The final product can be used as a nutraceutical oil or as an ingredient to enhance the food's physical properties.

Glycerol esterification of free fatty acids catalyzed by zinc glycerolate for biodiesel production from acidified palm oil: Optimization, kinetic study, and process evaluation

AbstractBiodiesel is an important alternative renewable liquid fuel due to its eco‐friendly, non‐toxic, and lower emissions. In this work, glycerol esterification catalyzed by zinc glycerolate was employed as a pretreatment to prepare biodiesel from acidified palm oil. The effects of stirring rate, catalyst amount, glycerol to free fatty acids (FFAs) molar ratio, and reaction temperature on the conversion of FFAs and concentration of monoglycerides, diglycerides, and triglycerides were investigated and optimized. The results show that the conversion of FFAs could reach 99.16% under the optimized conditions. Moreover, the kinetics of glycerol esterification catalyzed by zinc glycerolate at 160–200°C was obtained. Additionally, a comprehensive evaluation of the new biodiesel production process was also conducted. As a result, higher biodiesel content in the crude biodiesel phase was obtained after transesterification and separation using this new process. Overall, the study contributes to the utilization of waste oils to produce renewable energy and to minimize the waste management problem.

Effects of exogenous calcium and calcium inhibitor on physiological characteristics of winter turnip rape (Brassica rapa) under low temperature stress

Low temperature is one of the environmental factors that restrict the growth and geographical distribution of Brassica. To investigate the effects of exogenous calcium and calcium inhibitor on the ability of winter turnip rapeseed (Brassica rapa L.) to withstand low temperatures (4℃), we used a strong cold-resistant variety Longyou 7 (L7) and a weak cold-resistant variety Longyou 99 (L99) as the materials. The seedlings were treated with CaCl2 (20 mmol·L-1) and calcium inhibitor LaCl3 (10 mmol·L-1) at 0 h (CK), 6 h, 12 h, 24 h and 48 h after 4℃ treatments. Physiological characteristics, Ca2+ flux and Ca2+ concentration in roots after treatments were analyzed. Results illustrated that under 4℃ treatment, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased by both CK and exogenous CaCl2 treatments. Contents of soluble protein (SP) and proline (Pro) increased, while contents of malondialdehyde (MDA) decreased, resulting in reduced membrane lipid peroxidation. But enzyme activity decreased and MDA content increased following treatment with exogenous LaCl3. The rate of Ca2+ flow showed a higher uptake in L7 roots compared with L99. L99 showed Ca2+ efflux with a rate of 30.21 pmol‧cm-2‧s-1, whereas L7 showed short efflux then returned to influx. Calcium ion content in roots decreased in both cultivars after CaCl2 treatment. Results of RNA-seq revealed that genes were differentially expressed in response to low temperatures, hormones, photosystem II, chloroplasts, DNA replication, ribosomal RNA processing, and translation. This study found significant expression genes related to cellular signal transduction (MAPK signaling pathway) and material metabolism (nitrogen metabolism, glycerol ester metabolism).It was also analyzed by WGCNA that two modules had the strongest correlation with physiological indicators. Eight candidate genes were identified among MAPK signaling pathway and the two modules.

Systematic evaluation of the correlation between serum metabolites and tinnitus

Objective: We performed a Mendelian randomisation (MR) analysis to explore the relationship between serum metabolites and tinnitus. Methods: In this study, 486 serum metabolites were considered as exposure factors, and single nucleotide polymorphisms (SNP) significantly associated with them were used as instrumental variables (IV). The serum metabolite data were obtained from a public database (http://metabolomips.org/gwas/index.php), while the genome-wide association study (GWAS) summary association statistics for tinnitus were obtained from a Finnish database (https://r10.finngen.fi/pheno/H8_TINNITUS). The inverse variance weighting (IVW) method was employed as the primary determination method for MR analysis, with corrections for multiple comparisons made using the false discovery rate (FDR). Sensitivity tests were conducted using the MR-Egger regression, Mendelian random polymorphism residuals and outliers (MR-PRESSO) methods. The identified serum metabolites were subjected to chained disequilibrium regression analysis (LDSC) and metabolic pathway analysis. Reverse MR analysis was performed to investigate the possibility of reverse causality. Analyses were performed in R software (version 4.3.1). Results: A total of 17 serum metabolites (including 10 known and 7 unknown metabolites) associated with tinnitus were identified. The known metabolites included protective metabolites such as acetylcarnitine, hydroxyisovaleryl carnitine, glycine, monounsaturated glycerol ester, and glycine-L-valine, and hazardous metabolites such as allantoin, glycerylphosphorylcholine 1-eicosatrienoate, myo-inositol, 15-methylpalmitate, and pseudouridine; the strongest causally protective metabolites were acetylcarnitine, the followed by hydroxyisopentanoyl carnitine and glycine; the hazardous metabolite with the strongest causal effect was pseudouridine, followed by inositol and 15-methylpalmitate; and only hydroxyisopentanoyl carnitine (PFDR=0.04) and glycerol monooleate (PFDR=0.04) reached significance values after FDR correction. The findings were free of heterogeneity, pleiotropy and reverse causal associations. The metabolic pathways were mainly enriched in pathways such as ascorbic acid and aldolac metabolism. Conclusions: The study suggests a causal relationship between serum metabolites and tinnitus risk. Serum metabolite levels may influence tinnitus-related metabolic pathways.

Investigation on the Performances of Esterified Waste Cooking Oil Rejuvenator and Recycled Asphalt.

Waste cooking oil (WCO) recycled asphalt is facing issues regarding insufficient thermal oxidation stability and aging resistance. In this research, glycerol esterification was adopted to pretreat WCO, and the consequences of this treatment on the aging resistance and thermal stability of WCO were analyzed. The impacts of varying levels of esterification of WCO on the high-temperature, low-temperature performances, fatigue properties, and aging resistance of recycled asphalt were investigated. Furthermore, the mechanisms of regeneration and the anti-aging of deeply esterified WCO recycled asphalt were revealed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) tests. The results indicated that variations in the physical properties of WCO during the aging process were reduced, and its aging resistance was improved following glycerol esterification therapy. The initial thermal decomposition temperature was increased by approximately 115 °C, which resulted in the enhancement of thermal stability significantly. Recycled asphalt obtained from deeply esterified WCO exhibited superior high-temperature, low-temperature performances, and fatigue properties. Moreover, the thermal oxidation stability and aging resistance of recycled asphalt with deep-esterified WCO could be promoted by reducing the oxidation and volatilization of light components during the aging process, with the complex modulus ageing resistance index decreasing by 13.27% and the phase angle ageing resistance index increasing by 14.71%.

Enhanced Glycerolysis of Fatty Acid Methyl Ester by Static Mixer Reactor.

This study investigates the synthesis of monoglycerides (MGs) and diglycerides (DGs) from glycerol (G) and fatty acid methyl ester (FAME) using a static mixer reactor (SMR), which combines a static mixer (SM) with a reactor tank. The SMR integrates Kenics static mixers (KSM) and low-pressure drop static mixers (LPDSM) with varying length-to-diameter ratios (L/D = 1.0 and 1.5). Keys glycerolysis parameters, including the G:FAME molar ratio of 2:1-3:1, 2-3 wt % potassium hydroxide (KOH), and reaction time of 30-90 min at 150 °C were systematically explored. The SMR design allows precise control over the reaction time without altering the feed flow rate or tube length and avoiding agitator leakage. The optimal operating conditions, determined through a face-centered central composite design, resulted in 71.35% MGs and 14.20% DGs at a 3:1 molar ratio of G to FAME, 3 wt % KOH, 60 min, and 150 °C using an LPDSM with an L/D of 1.5. In comparison, an LPDSM with an L/D of 1 achieved 79.28% MGs and 10.17% DGs under the same conditions. When applied to purified crude glycerol, these conditions yielded 61.09% MGs and 23.44% DGs. The study found that a lower L/D ratio improved the mixing efficiency but increased the pressure drop. The SMR demonstrated superior performance in glycerolysis compared with conventional stirred tank reactors and ultrasonic probe reactors, indicating its potential for enhanced industrial application.

Leaf Gas Film 1 promotes glycerol ester accumulation and formation of a tight root barrier to radial O2 loss in rice.

Rice (Oryza sativa L.) and many other wetland plants form an apoplastic barrier in the outer parts of the roots to restrict radial O2 loss to the rhizosphere during soil flooding. This barrier facilitates longitudinal internal O2 diffusion via gas-filled tissues from shoot to root apices, enabling root growth in anoxic soils. We tested the hypothesis that Leaf Gas Film 1 (LGF1), which influences leaf hydrophobicity in rice, plays a crucial role in tight outer apoplastic barriers formation in rice roots. We examined the roots of a rice mutant (dripping wet leaf 7, drp7) lacking functional LGF1, its wild type, and an LGF1 overexpression line for their capacity to develop outer apoplastic barriers that restrict radial O2 loss. We quantified the chemical composition of the outer part of the root and measured radial O2 diffusion from intact roots. The drp7 mutant exhibited a weak barrier to radial O2 loss compared to the wild type. However, introducing functional LGF1 into the mutant fully restored tight barrier function. The formation of a tight barrier to radial O2 loss was associated with increased glycerol ester levels in exodermal cells, rather than differences in total root suberization or lignification. These results demonstrate that, in addition to its role in leaf hydrophobicity regulation, LGF1 plays an important role in controlling the function of the outer apoplastic barriers in roots. Our study suggests that increased deposition of glycerol esters in the suberized root exodermis establishes a tight barrier to radial O2 loss in rice roots.

Reinforcement of hydroxyapatite bone cement via thin glycerol-citrate polyester infiltration: Microstructural, mechanical and in-vitro evaluation

The development of calcium phosphate cements (CPCs) incorporating biopolymers, such as thermoplastic polylactides, is known as an efficient strategy to enhance the physico-chemical, biological, and mechanical properties of CPCs. However, the use of thermosetting polyol citrates as fillers in CPCs has rarely been reported. Hence, the main goal of the present work was to produce composite CPCs based on tetracalcium phosphate–monetite cement matrix (C) and glycerol-citrate polyester (GCA) and to thoroughly study the effect of GCA addition on microstructural, micro, and nano-mechanical as well as in-vitro cellular properties of final cement composites. The GCA polymer was synthesized by esterification of glycerol with citric acid and coated on the C cement powder matrix at a concentration of 2.5 wt% by infiltration in ethanol solution. Two systems were prepared, by drying the composite powder at 105 and 170 °C (denoted as GCA/C105 and GCA/C170), while the respective composite cements were produced by mixing the powders with the 2 wt% of NaH2PO4 liquid phase. The results showed that the GCA polyester had no significant effect on the hydrolysis and transformation of the original cement matrix, and the nanocrystalline hydroxyapatite (Hap) was found as the main hydration product in all types of cement. The cement setting time decreased slightly with the GCA addition. On the other hand, a significant increase in mechanical properties was reached by introducing the GCA polyester into the CPC matrix, achieving more than a 70 % increase in the compressive strength, and about 50 % and 20 % in micro and nanohardness values compared to that obtained for the original C cement sample. The nanoindentation analysis revealed that the improved compressive strength and hardness were due to the stronger boundaries between the platelet-like hydroxyapatite particles in GCA-doped cements and partially caused by the denser, less porous, and more compact microstructures. The results of in-vitro cytotoxicity testing revealed high proliferation activity of the osteoblastic cells in all cement extracts, providing useful information for designing novel composite cements with the potential to be applied as bone substitute materials.

A Short Review: The Use and Application of Matrix Resins Formed with Some Plant-Based Oils in Bio-Composite Materials

Increasing environmental problems, waste recycling problems, and non-biodegradable resources have led researchers to different searches for composite materials in recent years. In these studies, interest in bio-composite materials known as green composites has increased significantly due to their potential to replace traditional materials in material production. The creation of biocomposite materials from natural fibers or natural resins instead of synthetic fibers and synthetic resins has made natural resources the focus of researchers. Among these natural resin formations, the use of vegetable-based oils in various applications has started to be seen frequently due to their low cost, biodegradability, and availability. In addition to being recyclable, vegetable-based oils are an important alternative in many sectors, especially in the chemical industry, both environmentally and economically, with a wide variety of chemical conversion possibilities. The desire to explore the versatility of vegetable oil components formed by the complex multi-component mixtures of fatty acids and glycerol ester accelerates the studies in this field even more. In this study, the chemical compositions of vegetable oils hybridized with different resins, the chemical structures of pure vegetable oils, the different varieties among these vegetable oils, and various types of biocomposites produced using vegetable oil-based resins were investigated. In addition, the latest trends in other applications of these bio-composites, especially in automotive, were examined.

Understanding the reaction dynamics of glycerol conversion into glycerol carbonate by transesterification of carbonic acid esters over CaO

The conversion of glycerol into value-added products is crucial for reducing waste generation in the biodiesel industry. In this context, glycerol carbonate has emerged as a promising molecule, capable of being produced through various processes, with glycerol transesterification being considered the most environmentally friendly method. In order to investigate the transesterification process comprehensively, this work focused on reactions between glycerol and different carbonic acid esters (dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate), utilizing calcium oxide (CaO) as a basic catalyst. The catalyst was obtained commercially and characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The catalyst characterizations showed that it consisted of nano and micrometric particles with high purity, making it suitable for use without prior pretreatment. The reactions were conducted in a batch reactor using dimethylformamide as a solvent, and the products were analyzed by gas chromatography (GC-FID and GC-MS). Experiments were performed to investigate the effects of different reaction parameters on the formation process of glycerol carbonate and potential co-products. CaO showed moderate catalytic activity in glycerol conversion, which occurred in three steps, forming glycerol carbonate with high selectivity, along with small amounts of co-products, glycidol and glycerol tricarbonate. Thus, considering the results obtained in this and other studies, it was possible to identify that moderately strong basic catalysts favor simple reaction mechanisms, predominantly yielding glycerol carbonate. Conversely, highly basic catalysts induce more complex reaction mechanisms, resulting in significant formation of co-products.

Three new compounds from the fruits of Solanum virginianum L. and their anti-inflammatory activities

Three new compounds 1-glyceryl 9(β), 10(α), 11(β)-trihydroxy-12(Z)-octadecenoate, 2’S-20-O-p-hydroxyphenylpropionyloxy-20-hyd­roxyarachidic acid glycerol ester (2), 3-O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside of ethyl (3S)-hydroxybutanoate (3), as well as a new natural product (4) were isolated from the fruits of Solanum virginianum L. The structures of 26 compounds were determined by comprehensive spectroscopic analyses, NMR calculation, chemical methods, and comparisons of spectroscopic data. Compounds 2 and 16 exhibited good anti-inflammatory activity in the LPS-induced RAW 264.7 inflammatory model with IC50 values of 16.75 ± 1.54 and 22.43 ± 2.01 μM, respectively.

Development of biobased, sustainable and environmentally friendly glycerol ester rosins for the production of thermoplastic road marking paint

AbstractIn recent years, natural rosin derivatives have gained significant importance in the production of sustainable bio‐based materials, including thermoplastic road marking paint (TRMP). This study evaluates the use of sustainable natural glycerol ester rosins as bio‐based binders in TRMP formulations, specifically focusing on pine, wood, and tall oil rosins. Various analytical techniques, such as FT‐IR, TGA, MALDI‐TOF‐MS and GPC‐HPLC, were utilized to analyze both unmodified and glycerol ester rosins. Standard tests, including acid number (mg KOH/g) ASTM D 465‐05 and softening point (°C) ASTM E 28‐99, were also conducted on the samples. The optimum synthesis conditions for glycerol ester rosins (GER) were determined as follows: a rosin/glycerol molar ratio of 2.54, catalyst/rosin weight ratio of 0.5%, and antioxidant/rosin weight ratio of 1.0%. GPC‐HPLC analysis revealed average esterification reaction yields of over 90.85%. Furthermore, TRMPs underwent various tests, including gloss factor (β), chromaticity coordinates (x, y), UVB aging, and softening point (°C). The results demonstrated that GERs exhibited superior performance, especially in the UVB aging test, with all TRMPs classified as UV1 type. These findings highlight the promising potential of GERs derived from different types of rosins in producing sustainable, environmentally friendly, and bio‐based next‐generation TRMPs.

Role of heads and tails on tetrahydrofuran- and dimethyl sulfoxide-water separation by glycerol and sucrose esters

Tetrahydrofuran (THF) and dimethylsulfoxide (DMSO) are miscible in water due to hydrogen (H) bonding. Amphiphilic glycerol and sucrose esters with a different number of tails and heads separate them, depending on the organic solvent concentration. Separation is worse in solutions where amphiphiles are most soluble. Separation occurs due to interactions between the amphiphiles and either organic solvents or water, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Separation is best with glycerol esters with more heads and tails. Multiple tails hamper interactions between glycerol ester heads, thereby facilitating interactions with organic solvents or water to promote solvent–water separation. THF interacts with the glycerol ester tails, while water H bonds with the glycerol ester heads, as indicated by activity coefficients estimated with conductor-like screening model for real solvents. In THF, amphiphiles self-assemble into micelles, as shown by small angle x ray scattering (SAXS). Without water, THF is likely both inside and outside the micelles. SAXS shows that micelles shrink with 4% water in THF because water molecules partition inside them and are smaller than THF. With additional water, micelles swell into emulsions. Dissimilar to THF, DMSO preferentially interacts with the glycerol ester heads rather than their tails. ATR-FTIR shows that the proportion of free vs bonded S=O groups of DMSO decreases upon mixing with glycerol esters. DMSO and glycerol esters primarily accept H bonds, as indicated by their sigma profile. This leads to competition for interactions with water, displacing DMSO.

Enzymatic conversion of camellia seed oil into glycerol esters: Synthesis and characterization

AbstractThe conversion of triacylglycerols in edible oils into diacylglycerols (DAGs) is of great significance for obtaining products with health benefits. Camellia seed oil (C‐oil), which is rich in oleic acid and linoleic acid, is an excellent raw material for the production of DAGs. In this study, single factor optimization experiments were carried out for hydrolysis and esterification respectively. Using Lipozyme® RM IM as catalyst, the maximum percent of C‐oil hydrolysis reached 87.14% at the reaction temperature of 60°C, reaction time of 24 h, water content of 30% and enzyme addition amount of 4%. The maximum content of camellia seed oil diacylglycerol (C‐DAG) reached 62.49% under the conditions of Lipozyme® RM IM as catalyst, vacuum system, 3% enzyme addition, 2% water addition, reaction temperature of 50°C and substrate molar ratio of free fatty acid to glycerol of 1:1. The high content of DAG was obtained by a coupled method, which eliminated the purification steps and reduced production costs. C‐oil and C‐DAG have been characterized by GC, TG, DSC, and GC‐IMS. Our results showed that the enzymatic coupling method did not affect the structural of the substances, but did affect the crystallization and melting properties of the oils. Moreover, the taste of C‐DAG was more delicate than C‐oil. Finally, the reaction mechanism was analyzed using FTIR spectroscopy, revealing that C‐oil was primarily hydrolyzed into free fatty acids. C‐DAG exhibited ester C‐O stretching vibrations in the range 1280–1030 cm−1, indicating successful esterification reaction between camellia seed oil free fatty acids (C‐FFAs) and glycerol catalyzed by lipases.

A polysubstituted cyclopentane and two glycerol esters from the engineered strain Streptomyces sp. S35-LAL1

Activation of silencing gene clusters is an important way to discover structurally novel compounds. In this study, three undescribed compounds were obtained from an engineered strain of Streptomyces sp. S35-LAL1. They include a polysubstituted cyclopentane with an unprecedented 10-carbon skeleton (1) and two glycerol esters (2 and 3). The structures of compounds 1–3 were elucidated through analysis of their spectroscopic data including 1D, 2D NMR, optical rotation, and electronic circular dichroism (ECD).

Review:Medical Benefits Of Stearic Acid For Skin And Its Role In Treatment Of Some Diseases

Stearic acid is one of the most common fatty acids. It is a glycerol ester found in most lipids from plants and animals. Being an emollient, stearic acid acts by smoothing and softening the skin. It has been consistently shown that, in comparison to other saturated fats, stearic acid either has no effect on low blood cholesterol or has a neutral effect. A diet high in stearic acid was found to reduce fasting levels of coagulation factor VII that causes blood clotting. There doesn't seem to be any connection between stearic acid and a higher incidence of heart attacks or ischemic heart disease. Stearic acid preferentially stimulates apoptosis, or programmed cell death, in malignant vs non-cancerous breast cancer cells and suppresses important cell cycle checkpoints, preventing breast cancer cells from proliferating. In neurodegenerative illnesses such as Parkinson's disease, stearic acid might be protective.

Esterification of Cyclic N6-Threonylcarbamoyladenosine During RNA Sample Preparation.

The continuous deciphering of crucial biological roles of RNA modifications and their involvement in various pathological conditions, together with their key roles in the use of RNA-based therapeutics, has reignited interest in studying the occurrence and identity of non-canonical ribonucleoside structures during the past years. Discovery and structural elucidation of new modified structures is usually achieved by combination of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) at the nucleoside level and stable isotope labeling experiments. This approach, however, has its pitfalls as demonstrated in the course of the present study: we structurally elucidated a new nucleoside structure that showed significant similarities to the family of (c)t6A modifications and was initially considered a genuine modification, but subsequently turned out to be an in vitro formed glycerol ester of t6A. This artifact is generated from ct6A during RNA hydrolysis upon addition of enzymes stored in glycerol containing buffers in a mildly alkaline milieu, and was moreover shown to undergo an intramolecular transesterification reaction. Our results demand for extra caution, not only in the discovery of new RNA modifications, but also with regard to the quantification of known modified structures, in particular chemically labile modifications, such as ct6A, that might suffer from exposure to putatively harmless reagents during the diverse steps of sample preparation.

Mono- to tetra-alkyl ether cardiolipins in a mesophilic, sulfate-reducing bacterium identified by UHPLC-HRMSn: a novel class of membrane lipids.

The composition of membrane lipids varies in a number of ways as adjustment to growth conditions. Variations in head group composition and carbon skeleton and degree of unsaturation of glycerol-bound acyl or alkyl chains results in a high structural complexity of the lipidome of bacterial cells. We studied the lipidome of the mesophilic, sulfate-reducing bacterium, Desulfatibacillum alkenivorans strain PF2803T by ultra-high-pressure liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMSn). This anaerobic bacterium has been previously shown to produce high amounts of mono-and di-alkyl glycerol ethers as core membrane lipids. Our analyses revealed that these core lipids occur with phosphatidylethanomamine (PE) and phosphatidylglycerol (PG) head groups, representing each approximately one third of the phospholipids. The third class was a novel group of phospholipids, i.e., cardiolipins (CDLs) containing one (monoether/triester) to four (tetraether) ether-linked saturated straight-chain or methyl-branched alkyl chains. Tetraether CDLs have been shown to occur in archaea (with isoprenoid alkyl chains) but have not been previously reported in the bacterial Domain. Structurally related CDLs with one or two alkyl/acyl chains missing, so-called monolyso-and dilyso-CDLs, were also observed. The potential biosynthetic pathway of these novel CDLs was investigated by examining the genome of D. alkenivorans. Three CDL synthases were identified; one catalyzes the condensation of two PGs, the other two are probably involved in the condensation of a PE with a PG. A heterologous gene expression experiment showed the in vivo production of dialkylglycerols upon anaerobic expression of the glycerol ester reductase enzyme of D. alkenivorans in E. coli. Reduction of the ester bonds probably occurs first at the sn-1 and subsequently at the sn-2 position after the formation of PEs and PGs.

Lipidomics study of Liujunzi decoction in hyperlipidemia rats with spleen deficiency based on UPLC-Q-TOF/MS

Hyperlipidemia refers to the abnormal levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) in peripheral blood circulation. It is a predominant risk factor underlying cardiovascular and cerebrovascular diseases, including coronary heart disease and atherosclerosis. Furthermore, it is also one of the most prevalent chronic diseases globally. Liujunzi Decoction is the basic prescription for the treatment of spleen and stomach diseases. It can tonify the spleen and qi, remove dampness, and reduce turbidity. Moreover, it is also clinically used for the treatment of spleen deficiency hyperlipidemia. However, its metabolites and therapeutic effect on spleen deficiency hyperlipidemia have not been comprehensively determined in vitro and in vivo. This study established a rat model of spleen deficiency hyperlipidemia by inducing starvation and satiety disorders, exhaustion swimming, and intragastric administration of the fat emulsion. To identify related metabolite changes and serum lipid composition, UPLC-Q-TOF-MS, PCA, and OPLS-DA lipidological methods were performed. The results demonstrated significant changes in rat's signs during the modeling process, which were consistent with the criteria for the syndrome differentiation of spleen deficiency in traditional Chinese medicine. Furthermore, this study identified 100 potential biomarkers in rat serum, of which 52 were associated with lipid synthesis, such as LPC, PC, PI, PE, PA, Cer, SM, etc. The pathways involved were glycerol phospholipid, sphingomyelin, and glycerol ester metabolisms. After the Liujunzi decoction intervention, 56 potential biomarkers were observed in the high-dose group, alleviating the metabolic spectrum imbalance by reducing metabolite levels. In addition, metabolic pathway disturbances were markedly improved. This study provides references for future studies on Liujunzi decoction and furnishes essential data for assessing the relationships between chemical constituents and pharmacological activities of Liujunzi decoction.

Lipase-Responsive Lignin Composite Nanoparticles for the Delivery of Insoluble Bioactives.

Low solubility and chemical instability are the main problems with insoluble bioactives. Lignin, with its exceptional biological properties and amphiphilicity, holds promise as a delivery system material. In this study, glycerol esters were incorporated into alkali lignin (AL) through ether and ester bonds, resulting in the successful synthesis of three hydrophobically modified alkali lignins (AL-OA, AL-OGL, and AL-SAN-OGL). Subsequently, lignin composite nanoparticles (LNPs@BC) encapsulating β-carotene were prepared using antisolvent and sonication techniques. The encapsulation rates were determined to be 37.69 ± 2.21%, 84.01 ± 5.55%, 83.82 ± 5.23%, and 83.11 ± 5.85% for LNP@BC-1, LNP@BC-2, LNP@BC-3, and LNP@BC-4, respectively, with AL, AL-OA, AL-OGL, and AL-SAN-OGL serving as the wall materials under optimized preparation conditions. The antioxidant properties and UV-absorbing capacity of the four lignins were characterized, demonstrating their efficacy in enhancing the oxygen and photostability of β-carotene. Following 6 h of UV irradiation, LNP@BC-4 exhibited a retention rate of 83.03 ± 2.85% for β-carotene, while storage under light-protected conditions at 25 °C for 7 days retained 73.33 ± 7.62% of β-carotene. Furthermore, the encapsulated β-carotene demonstrated enhanced thermal and storage stability. In vitro release experiments revealed superior stability of LNPs@BC in simulated gastric fluid (SGF), with β-carotene retention exceeding 77% in both LNP@BC-3 and LNP@BC-4. LNP@BC-4 exhibited the highest bioaccessibility in simulated intestinal fluid (SIF) at 46.96 ± 0.80%, that LNP@BC-1 only achieved 10.87 ± 0.90%. The enzymatic responsiveness of AL-OGL and AL-SAN-OGL was confirmed. Moreover, LNPs@BC exhibited no cytotoxicity toward L929 cells and demonstrated excellent hemocompatibility. In summary, this study introduces a novel enzyme-responsive modified lignin that has promising applications in the fields of food, biomedicine, and animal feed.