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Molecules (Basel, Switzerland) May 2019The role of glycerol as a green bio-based solvent, reactant, and/or a catalyst in the synthesis of novel heterocycles, under pressure, is studied. Synthesis of novel...
The role of glycerol as a green bio-based solvent, reactant, and/or a catalyst in the synthesis of novel heterocycles, under pressure, is studied. Synthesis of novel quinolines in good yields using a new modified Skraup synthesis, utilizing glycerol and pressure Q-tubes, is demonstrated. Novel aniline trimers are prepared using glycerol, and substituted anilines under pressure, in acidic medium and water. Glycerol was employed as a catalyst and a green solvent in the synthesis of novel pyridazines -. The mechanisms of the reactions and the catalytic effect of glycerol in protic and aprotic media are fully discussed. The structures of the synthesized compounds were determined via X-ray crystallography and spectroscopic methods.
Topics: Aniline Compounds; Catalysis; Glycerol; Green Chemistry Technology; Molecular Structure; Quinolines
PubMed: 31083287
DOI: 10.3390/molecules24091806 -
Redox Biology Jul 2023Glycerol is a substrate for gluconeogenesis and fatty acid esterification in the liver, processes which are upregulated in obesity and may contribute to excess fat...
BACKGROUND
Glycerol is a substrate for gluconeogenesis and fatty acid esterification in the liver, processes which are upregulated in obesity and may contribute to excess fat accumulation. Glycine and glutamate, in addition to cysteine, are components of glutathione, the major antioxidant in the liver. In principle, glycerol could be incorporated into glutathione via the TCA cycle or 3-phosphoglycerate, but it is unknown whether glycerol contributes to hepatic de novo glutathione biosynthesis.
METHODS
Glycerol metabolism to hepatic metabolic products including glutathione was examined in the liver from adolescents undergoing bariatric surgery. Participants received oral [U-C]glycerol (50 mg/kg) prior to surgery and liver tissue (0.2-0.7g) was obtained during surgery. Glutathione, amino acids, and other water-soluble metabolites were extracted from the liver tissue and isotopomers were quantified with nuclear magnetic resonance spectroscopy.
RESULTS
Data were collected from 8 participants (2 male, 6 female; age 17.1 years [range 14-19]; BMI 47.4 kg/m [range 41.3-63.3]). The concentrations of free glutamate, cysteine, and glycine were similar among participants, and so were the fractions of C-labeled glutamate and glycine derived from [U-C]glycerol. The signals from all component amino acids of glutathione - glutamate, cysteine and glycine - were strong and analyzed to obtain the relative concentrations of the antioxidant in the liver. The signals from glutathione containing [C]glycine or [C]glutamate derived from the [U-C]glycerol drink were readily detected, and C-labelling patterns in the moieties were consistent with the patterns in corresponding free amino acids from the de novo glutathione synthesis pathway. The newly synthesized glutathione with [U-C]glycerol trended to be lower in obese adolescents with liver pathology.
CONCLUSIONS
This is the first report of glycerol incorporation into glutathione through glycine or glutamate metabolism in human liver. This could represent a compensatory mechanism to increase glutathione in the setting of excess glycerol delivery to the liver.
Topics: Humans; Liver; Glutathione; Glycerol; Male; Female; Adolescent; Young Adult; Magnetic Resonance Spectroscopy
PubMed: 37224695
DOI: 10.1016/j.redox.2023.102749 -
International Journal of Biological... Mar 2024With the rapid development of biodiesel, biodiesel-derived glycerol has become a promising renewable bioresource. The key to utilizing this bioresource lies in the... (Review)
Review
With the rapid development of biodiesel, biodiesel-derived glycerol has become a promising renewable bioresource. The key to utilizing this bioresource lies in the value-added conversion of crude glycerol. While purifying crude glycerol into a pure form allows for diverse applications, the intricate nature of this process renders it costly and environmentally stressful. Consequently, technology facilitating the direct utilization of unpurified crude glycerol holds significant importance. It has been reported that crude glycerol can be bio-transformed or chemically converted into high-value polymers. These technologies provide cost-effective alternatives for polymer production while contributing to a more sustainable biodiesel industry. This review article describes the global production and quality characteristics of biodiesel-derived glycerol and investigates the influencing factors and treatment of the composition of crude glycerol including water, methanol, soap, matter organic non-glycerol, and ash. Additionally, this review also focused on the advantages and challenges of various technologies for converting crude glycerol into polymers, considering factors such as the compatibility of crude glycerol and the control of unfavorable factors. Lastly, the application prospect and value of crude glycerol conversion were discussed from the aspects of economy and environmental protection. The development of new technologies for the increased use of crude glycerol as a renewable feedstock for polymer production will be facilitated by the findings of this review, while promoting mass market applications.
Topics: Glycerol; Biofuels; Polymers; Fermentation; Conservation of Natural Resources
PubMed: 38278390
DOI: 10.1016/j.ijbiomac.2024.129536 -
Anesthesia and Analgesia May 2015
Topics: Anesthetics, Intravenous; Animals; Excipients; Glycerol; Male; Pregnanediones; Propofol; Water; beta-Cyclodextrins
PubMed: 25899261
DOI: 10.1213/ANE.0000000000000667 -
PLoS Pathogens Dec 2018Bloodstream form African trypanosomes are thought to rely exclusively upon glycolysis, using glucose as a substrate, for ATP production. Indeed, the pathway has long...
Bloodstream form African trypanosomes are thought to rely exclusively upon glycolysis, using glucose as a substrate, for ATP production. Indeed, the pathway has long been considered a potential therapeutic target to tackle the devastating and neglected tropical diseases caused by these parasites. However, plasma membrane glucose and glycerol transporters are both expressed by trypanosomes and these parasites can infiltrate tissues that contain glycerol. Here, we show that bloodstream form trypanosomes can use glycerol for gluconeogenesis and for ATP production, particularly when deprived of glucose following hexose transporter depletion. We demonstrate that Trypanosoma brucei hexose transporters 1 and 2 (THT1 and THT2) are localized to the plasma membrane and that knockdown of THT1 expression leads to a growth defect that is more severe when THT2 is also knocked down. These data are consistent with THT1 and THT2 being the primary routes of glucose supply for the production of ATP by glycolysis. However, supplementation of the growth medium with glycerol substantially rescued the growth defect caused by THT1 and THT2 knockdown. Metabolomic analyses with heavy-isotope labelled glycerol demonstrated that trypanosomes take up glycerol and use it to synthesize intermediates of gluconeogenesis, including fructose 1,6-bisphosphate and hexose 6-phosphates, which feed the pentose phosphate pathway and variant surface glycoprotein biosynthesis. We used Cas9-mediated gene knockout to demonstrate a gluconeogenesis-specific, but fructose-1,6-bisphosphatase (Tb927.9.8720)-independent activity, converting fructose 1,6-bisphosphate into fructose 6-phosphate. In addition, we observed increased flux through the tricarboxylic acid cycle and the succinate shunt. Thus, contrary to prior thinking, gluconeogenesis can operate in bloodstream form T. brucei. This pathway, using glycerol as a physiological substrate, may be required in mammalian host tissues.
Topics: Gluconeogenesis; Glycerol; Substrate Specificity; Trypanosoma brucei brucei
PubMed: 30589893
DOI: 10.1371/journal.ppat.1007475 -
Molecules (Basel, Switzerland) Mar 2022To utilize excess glycerol produced from the biodiesel industry, researchers are developing innovative methods of transforming glycerol into value-added chemicals. One... (Review)
Review
To utilize excess glycerol produced from the biodiesel industry, researchers are developing innovative methods of transforming glycerol into value-added chemicals. One strategy adopted is the conversion of glycerol into acetins, which are esters of glycerol that have wide applications in cosmetics, pharmaceuticals, food and fuel additives, and plasticizers and serve as precursors for other chemical compounds. Acetins are synthesized either by traditional chemical methods or by biological processes. Although the chemical methods are efficient, productive, and commercialized, they are "non-green", meaning that they are unsafe for the environment and consumers. On the other hand, the biological process is "green" in the sense that it protects both the environment and consumers. It is, however, less productive and requires further effort to achieve commercialization. Thus, both methodologies have benefits and drawbacks, and this study aims to present and discuss these. In addition, we briefly discuss general strategies for optimizing biological processes that could apply to acetins production on an industrial scale.
Topics: Biofuels; Fermentation; Glycerol
PubMed: 35408654
DOI: 10.3390/molecules27072255 -
Acta Biochimica Polonica 2017The dairy propionibacteria, which are traditionally used for the production of Swiss cheeses, are able to synthesize valuable biomolecules, e.g. B group vitamins,...
The dairy propionibacteria, which are traditionally used for the production of Swiss cheeses, are able to synthesize valuable biomolecules, e.g. B group vitamins, propionic acid, and trehalose with unique chemical and physical properties. Both, dairy propionibacteria cells and trehalose, have found many applications as attractive and effective components in food, beauty and health care products. This study confirmed the ability of several strains from the Propionibacterium genus to create trehalose from glycerol. The research aimed to investigate the effect of crude and pure glycerol on biomass production and on trehalose accumulation by Propionibacterium freudenreichii ssp. shermanii 1. The results indicated that the capacity for trehalose accumulation by Propionibacterium spp. was strain dependent. Propionibacterium freudenreichii ssp. shermanii 1 was able to grow on crude glycerol. For both, pure and crude glycerol, the highest amount of dry biomass leveled off at about 4 g/L. While the use of crude glycerol had no effect on the final concentration of biomass, it reduced the accumulation of trehalose in the cells. An increase in the concentration of carbon source (2-8%) resulted in more than a 5-fold rise in trehalose production. The highest trehalose concentration of 195.04 mg/L was obtained with cultures of the said strain supplemented to 8% with pure glycerol.
Topics: Biomass; Fermentation; Glycerol; Propionates; Propionibacterium freudenreichii; Trehalose
PubMed: 29099120
DOI: 10.18388/abp.2017_1570 -
Colloids and Surfaces. B, Biointerfaces Apr 2024Despite the success of polyethylene glycol-based (PEGylated) polyesters in the drug delivery and biomedical fields, concerns have arisen regarding PEG's immunogenicity...
Despite the success of polyethylene glycol-based (PEGylated) polyesters in the drug delivery and biomedical fields, concerns have arisen regarding PEG's immunogenicity and limited biodegradability. In addition, inherent limitations, including limited chemical handles as well as highly hydrophobic nature, can restrict their effectiveness in physiological conditions of the polyester counterpart. To address these matters, an increasing amount of research has been focused towards identifying alternatives to PEG. One promising strategy involves the use of bio-derived polyols, such as glycerol. In particular, glycerol is a hydrophilic, non-toxic, untapped waste resource and as other polyols, can be incorporated into polyesters via enzymatic catalysis routes. In the present study, a systematic screening is conducted focusing on the incorporation of 1,6-hexanediol (Hex) (hydrophobic diol) into both poly(glycerol adipate) (PGA) and poly(diglycerol adipate) (PDGA) at different (di)glycerol:hex ratios (30:70; 50:50 and 70:30 mol/mol) and its effect on purification upon NPs formation. By varying the amphiphilicity of the backbone, we demonstrated that minor adjustments influence the NPs formation, NPs stability, drug encapsulation, and degradation of these polymers, despite the high chemical similarity. Moreover, the best performing materials have shown good biocompatibility in both in vitro and in vivo (whole organism) tests. As preliminary result, the sample containing diglycerol and Hex in a 70:30 ratio, named as PDGA-Hex 30%, has shown to be the most promising candidate in this small library analysed. It demonstrated comparable stability to the glycerol-based samples in various media but exhibited superior encapsulation efficiency of a model hydrophobic dye. This in-depth investigation provides new insights into the design and modification of biodegradable (di)glycerol-based polyesters, potentially paving the way for more effective and sustainable PEG-free drug delivery nano-systems in the pharmaceutical and biomedical fields.
Topics: Polyesters; Glycerol; Polyethylene Glycols; Drug Delivery Systems; Pharmaceutical Preparations; Adipates; Nanoparticles
PubMed: 38452625
DOI: 10.1016/j.colsurfb.2024.113828 -
Journal of Lipid Research Sep 2018It is a challenge to assess metabolic dysregulation in fatty liver of human patients prior to clinical manifestations. Here, we recruited obese, but otherwise healthy,...
It is a challenge to assess metabolic dysregulation in fatty liver of human patients prior to clinical manifestations. Here, we recruited obese, but otherwise healthy, subjects to examine biochemical processes in the liver with simple triglyceride accumulation using stable isotopes and NMR analysis of metabolic products in blood. Intrahepatic triglycerides were measured using H magnetic resonance spectroscopy, and volunteers received HO and [U-C]glycerol orally, followed by a series of blood draws. NMR analysis of plasma triglycerides and glucose provided detailed information about metabolic pathways in patients with simple hepatic steatosis. Compared with subjects with low hepatic fat, patients with hepatic steatosis were characterized by the following: lower C enrichments in the glycerol backbones of triglycerides (i.e., TG-[C]glycerol), higher [U-C]glycerol metabolism through the tricarboxylic acid (TCA) cycle, delayed gluconeogenesis from [U-C]glycerol, and less flexibility in adjusting supporting fluxes of glucose production upon an oral load of glycerol. In summary, simple hepatic steatosis was associated with enhanced [U-C]glycerol metabolism through pathways that intersect the TCA cycle and delayed gluconeogenesis from glycerol.
Topics: Adult; Fatty Liver; Female; Gluconeogenesis; Glycerol; Humans; Lipogenesis; Male; Middle Aged; Young Adult
PubMed: 30054343
DOI: 10.1194/jlr.M086405 -
Chemical Reviews Feb 2016The utility of metabolic synthons as the building blocks for new biomaterials is based on the early application and success of hydroxy acid based polyesters as... (Review)
Review
The utility of metabolic synthons as the building blocks for new biomaterials is based on the early application and success of hydroxy acid based polyesters as degradable sutures and controlled drug delivery matrices. The sheer number of potential monomers derived from the metabolome (e.g., lactic acid, dihydroxyacetone, glycerol, fumarate) gives rise to almost limitless biomaterial structural possibilities, functionality, and performance characteristics, as well as opportunities for the synthesis of new polymers. This review describes recent advances in new chemistries, as well as the inventive use of traditional chemistries, toward the design and synthesis of new polymers. Specific polymeric biomaterials can be prepared for use in varied medical applications (e.g., drug delivery, tissue engineering, wound repair, etc.) through judicious selection of the monomer and backbone linkage.
Topics: Amino Acids; Biocompatible Materials; Dihydroxyacetone; Glycerol; Hydroxy Acids; Molecular Structure; Polymers
PubMed: 26821863
DOI: 10.1021/acs.chemrev.5b00465