Articoli di riviste: "Glucose ester"

1

Leclercq-Meyer, Viviane, e Willy J. Malaisse. "Dual mode of action of glucose pentaacetates on hormonal secretion from the isolated perfused rat pancreas". American Journal of Physiology-Endocrinology and Metabolism 275, n. 4 (1 ottobre 1998): E610—E617. http://dx.doi.org/10.1152/ajpendo.1998.275.4.e610.

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Isolated perfused rat pancreases were exposed, in the presence of 10.0 mMl-leucine, to either α-d-glucose pentaacetate, β-l-glucose pentaacetate, or unesterified d-glucose, all tested at a 1.7 mM concentration. The pentaacetate ester of α-d-glucose and, to a lesser extent, that of β-l-glucose stimulated both insulin and somatostatin release, whereas unesterifiedd-glucose failed to do so. In the case of insulin output, the two esters differed from one another not solely by the magnitude of the secretory response but also by its time course and reversibility. Compared with these data, the most salient difference found in the case of somatostatin release consisted of the absence of an early secretory peak in response to α-d-glucose pentaacetate administration and the higher paired ratio between the secretory responses evoked by the esters of glucose and by unesterifiedd-glucose (5.5 mM) administered at the end of the experiments. The two esters provoked an initial and short-lived stimulation of glucagon secretion, in sharp contrast to the immediate inhibitory action of unesterifiedd-glucose. Thereafter, α-d-glucose pentaacetate, but not β-l-glucose pentaacetate, caused inhibition of glucagon release, such an effect being reversed when the administration of the ester was halted. These findings indicate a dual mode of action of glucose pentaacetate esters on hormonal secretion from the endocrine pancreas. The intracellular hydrolysis of α-d-glucose pentaacetate and subsequent catabolism of its hexose moiety may contribute to the early peak-shaped insulin response to this ester, to the persistence of a positive secretory effect in B and D cells after cessation of its administration, and to the late inhibition of glucagon release. However, a direct effect of the esters themselves, by some as-of-yet unidentified coupling process, is postulated to account for the stimulation of insulin and somatostatin release by β-l-glucose pentaacetate and for the initial enhancement of glucagon secretion provoked by both glucose esters.

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2

Malaisse, W. J., e A. Sener. "Metabolic effects and fate of succinate esters in pancreatic islets". American Journal of Physiology-Endocrinology and Metabolism 264, n. 3 (1 marzo 1993): E434—E440. http://dx.doi.org/10.1152/ajpendo.1993.264.3.e434.

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The metabolic effects and the catabolism of succinate methyl esters were examined in rat pancreatic islets. The esters augmented 14CO2 production from islets prelabeled with L-[U-14C]-glutamine but inhibited NH4+ output, suggesting that they do not activate glutamate dehydrogenase. They decreased 14CO2 output from islets prelabeled with [U-14C]palmitate. They had little effect on the oxidation of exogenous D-[3,4-14C]glucose, D-[2-14C]glucose, D-[6-14C]glucose, or D-[1-14C]glucose, suggesting unaltered ratio between the input of acetyl residues and four- or five-carbon metabolites, such as succinate, into the Krebs cycle. By following the fate of both [1,4-14C]succinate dimethyl ester and [2,3-14C]succinate dimethyl ester, data were obtained to indicate that succinate is efficiently formed from the ester and further metabolized, leading to the generation of 14C-labeled acidic metabolites including pyruvate and L-lactic acid, CO2, and amino acids. It is proposed that a concerted increase of both succinate and acetyl residue influx into the Krebs cycle accounts for the increase in O2 uptake caused by the succinate methyl esters and, hence, for stimulation of both pro-insulin biosynthesis and insulin release.

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3

Nottingham, Stephen F., Orestes T. Chortyk e Michael G. Stephenson. "Sugar Esters from Nicotiana Species as Potential Insecticides Against the Sweetpotato Whitefly (Homoptera: Aleyrodidae)". Journal of Entomological Science 31, n. 3 (1 luglio 1996): 331–39. http://dx.doi.org/10.18474/0749-8004-31.3.331.

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Eight Nicotiana species and three species accessions were grown and their sugar esters were isolated. Nicotiana trigonophylla, N. palmeri, and N. glutinosa gave the highest sugar ester yields. Sugar ester isolates were bioassayed at concentrations from 1.0 to 0.05 mg/ml against nymphs of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). The highest mortalities were observed with isolates from N. gossei and N. langsdorffii. As the sugar ester isolate from N. gossei contained both sucrose esters and glucose esters, these were bioassayed separately and both caused high mortality. The isolates of three N. glutinosa accessions varied in sucrose ester and labdane terpenoid content; labdane fractions were less toxic than sucrose ester fractions. Nicotiana glutinosa 24, N. langsdorffii, and N. trigonophylla, in addition to N. gossei, showed good potential as sources of biorational insecticide against whitefly.

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4

Ashraf-Khorassani, M., N. Nazem, LT Taylor e WM Coleman. "Isolation, Fractionation, and Identification of Sucrose Esters from Various Oriental Tobaccos Employing Supercritical Fluids". Beiträge zur Tabakforschung International/Contributions to Tobacco Research 23, n. 1 (1 aprile 2008): 32–45. http://dx.doi.org/10.2478/cttr-2013-0846.

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AbstractIsolation, fractionation, and identification of sucrose esters from aged oriental tobacco employing supercritical fluids have been completed. Underivatized sucrose ester-rich extracts were obtained using supercritical CO2 at densities greater than 0.73 g/mL. Lower density CO2 provided extracts with notable amounts of tobacco derived material; yet, no detectable sucrose ester content. Preparative supercritical fluid chromatography (SFC) provided for an additional purification of the sucrose ester-enriched fraction after column optimization. Structural assignments of the SFC fractions were facilitated using gas chromatography/mass spectrometry (GC/MS) accompanied by N, O-bis(trimethylsilyl)trifluoroacetamide-dimethylformamide (BSTFA-DMF) derivatization of the free hydroxyl groups and high performance-liquid chromatography/mass spectrometry (HPLC/MS). From a relative quantitative perspective regardless of tobacco type, sucrose esters having an acetyl group on C6 of the glucose function (Group III) were in higher concentration compared to both the concentration observed for sucrose ester of Group I (acetyl group on C3 of fructose) and sucrose ester of Group II (no acetyl group on either glucose or fructose). Saturated fatty acid constituents were found to range from a maximum total of 18 carbons to a minimum total of 13 carbons. Unsaturated and isomeric fatty acid homologues were detected within the Group II sucrose ester.

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5

Gross, Georg G., e Klaus Denzel. "Enzymatic Synthesis of Di-O-Phenylcarboxyl-ß-D-glucose Esters by an Acyltransferase from Oak Leaves". Zeitschrift für Naturforschung C 45, n. 1-2 (1 febbraio 1990): 37–41. http://dx.doi.org/10.1515/znc-1990-1-208.

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Leaves from oak (Quercus robur) contain an acyltransferase that catalyzes the conversion of β-glucogallin (1-O-galloyl-β-D-glucose) to 1,6-di-O-galloylglucose, an intermediate in the biosynthesis of gallotannins. Substrate specificity studies revealed th at this enzyme was also active with several structurally related 1-O-phenylcarboxyl-β-D-glucoses; appreciable reaction rates, however, were observed only in the form ation of 1,6-di-O-protocatechuoyl-β-D-glucose. This to date unknown ester, as well as its digalloyl analog, was synthesized using acyltransferase immobilized on phenyl-Sepharose, and characterized by UV and 1H NMR spectroscopy. In addition, the 1,2-di-O-β-D-glucose esters of benzoic and anisic acid were obtained in this investigation.

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6

Chang, Chin-Feng, Li-Chun Chen, Cheng-Jer Hsieh, Kai-Chun Chang e Jung-Jeng Su. "Characterization of polyhydroxyalkanoate-producing bacteria isolated from sludge of commercial pig farms for producing methyl esters". Water Science and Technology 68, n. 10 (24 ottobre 2013): 2171–77. http://dx.doi.org/10.2166/wst.2013.474.

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The objectives of this work were to isolate and characterize the polyhydroxyalkanoate (PHA) producing bacteria in enriched piggery sludge and make methyl esters from PHA for industrial applications. The strain ECAe24 isolated from piggery sludge with the highest PHA production was selected to produce PHA and then methyl ester by trans-esterification using glucose as substrate under mesophilic conditions. The final product after trans-esterification consisted of approximately 75.39% of fatty acid methyl ester and was identified as decanoic acid-3-hydroxy-methyl ester, octanoic acid-3-hydroxy-methyl ester, and some other contents. The novelty of this study is to use PHA-producing bacteria from piggery sludge to make fatty acid methyl esters which can be used as materials for producing biodiesel from piggery wastes.

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7

Wright, David C., Paige C. Geiger, Mark J. Rheinheimer, Dong Ho Han e John O. Holloszy. "Phorbol esters affect skeletal muscle glucose transport in a fiber type-specific manner". American Journal of Physiology-Endocrinology and Metabolism 287, n. 2 (agosto 2004): E305—E309. http://dx.doi.org/10.1152/ajpendo.00082.2004.

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Recent evidence has shown that activation of lipid-sensitive protein kinase C (PKC) isoforms leads to skeletal muscle insulin resistance. However, earlier studies demonstrated that phorbol esters increase glucose transport in skeletal muscle. The purpose of the present study was to try to resolve this discrepancy. Treatment with the phorbol ester 12-deoxyphorbol-13-phenylacetate 20-acetate (dPPA) led to an ∼3.5-fold increase in glucose transport in isolated fast-twitch epitrochlearis and flexor digitorum brevis muscles. Phorbol ester treatment was additive to a maximally effective concentration of insulin in fast-twitch skeletal muscles. Treatment with dPPA did not affect insulin signaling in the epitrochlearis. In contrast, phorbol esters had no effect on basal glucose transport and inhibited maximally insulin-stimulated glucose transport ∼50% in isolated slow-twitch soleus muscle. Furthermore, dPPA treatment inhibited the insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and the threonine and serine phosphorylation of PKB by ∼50% in the soleus. dPPA treatment also caused serine phosphorylation of IRS-1 in the slow-twitch soleus muscle. In conclusion, our results show that phorbol esters stimulate glucose transport in fast-twitch skeletal muscles and inhibit insulin signaling in slow-twitch soleus muscle of rats. These findings suggest that mechanisms other than PKC activation mediate lipotoxicity-induced whole body insulin resistance.

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8

Malaisse, Willy J., Carmen Sánchez-Soto, M. Elena Larrieta, Marcia Hiriart, Hassan Jijakli, Concepción Viñambres, María L. Villanueva-Peñacarrillo et al. "Insulinotropic action of α-d-glucose pentaacetate: functional aspects". American Journal of Physiology-Endocrinology and Metabolism 273, n. 6 (1 dicembre 1997): E1090—E1101. http://dx.doi.org/10.1152/ajpendo.1997.273.6.e1090.

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The functional determinants of the insulinotropic action of α-d-glucose pentaacetate were investigated in rat pancreatic islets. The ester mimicked the effect of nutrient secretagogues by recruiting individual B cells into an active secretory state, stimulating proinsulin biosynthesis, inhibiting86Rb outflow, and augmenting45Ca efflux from prelabeled islets. The secretory response to the ester was suppressed in the absence of Ca2+ and potentiated by theophylline or cytochalasin B. The generation of acetate from the ester apparently played a small role in its insulinotropic action. Thus acetate, methyl acetate, ethyl acetate, α-d-galactose pentaacetate, and β-d-galactose pentaacetate all failed to stimulate insulin release. The secretory response to α-d-glucose pentaacetate was reproduced by β-d-glucose pentaacetate and, to a lesser extent, by β-l-glucose pentaacetate. It differed from that evoked by unesterifiedd-glucose by its resistance to 3- O-methyl-d-glucose,d-mannoheptulose, and 2-deoxy-d-glucose. It is concluded that the insulinotropic action of α-d-glucose pentaacetate, although linked to the generation of the hexose from its ester, entails a coupling mechanism that is not identical to that currently implied in the process of glucose-induced insulin release.

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9

Zhang, T. M., H. Jijakli e W. J. Malaisse. "Nutritional efficiency of succinic acid and glutamic acid dimethyl esters in colon carcinoma cells". American Journal of Physiology-Gastrointestinal and Liver Physiology 270, n. 5 (1 maggio 1996): G852—G859. http://dx.doi.org/10.1152/ajpgi.1996.270.5.g852.

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The dimethyl esters of succinic acid (SAD) and glutamic acid (GME) were found to be efficiently metabolized in colon carcinoma cells of the Caco-2 line. The rate of [1,4-14C]SAD and [2,3-14C]SAD conversion to radioactive acidic metabolites, CO2, amino acids, pyruvic acid, and lactic acid suggested that the catabolism of the ester-derived succinic acid occurred mainly through the sequence of reactions catalyzed by succinate dehydrogenase, fumarase, and the malic enzyme. This coincided with a marked sparing action of SAD on the utilization of D-[2-(3)H]glucose and D-[5-(3)H]glucose and generation of 14C-labeled acid metabolites, CO2, and lactic acid from D-[U-14C]glucose by the enterocytes. Likewise, the conversion of [U-14C]GME to 14C-labeled amino acids, its oxidation compared with that of [1-(14)C]GME, and the production of NH4+ in the absence or presence of GME indicated efficient catabolism of the latter ester. Like SAD, GME decreased the utilization of D-[5-(3)H]glucose and generation of 14C-labeled acidic metabolites, pyruvate, and CO2 from D-[6-(14)C]glucose, while increasing the generation of 14C-labeled amino acids from the labeled hexose. The oxidation of D-[6-(14)C]glucose was even more severely inhibited by GME. In normal rat intestinal cells, SAM, SAD, and GME also exerted a marked sparing action on D-[U-14C]glucose oxidation. The present findings suggest, therefore, that these esters could possibly be used to sustain ATP generation in intestinal cells.

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10

Roberts, Dennis A., Liyi Wang, Weihe Zhang, Yi Liu, Pratik Shriwas, Yanrong Qian, Xiaozhuo Chen e Stephen C. Bergmeier. "Isosteres of ester derived glucose uptake inhibitors". Bioorganic & Medicinal Chemistry Letters 30, n. 18 (settembre 2020): 127406. http://dx.doi.org/10.1016/j.bmcl.2020.127406.

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11

Hansen, P. A., J. A. Corbett e J. O. Holloszy. "Phorbol esters stimulate muscle glucose transport by a mechanism distinct from the insulin and hypoxia pathways". American Journal of Physiology-Endocrinology and Metabolism 273, n. 1 (1 luglio 1997): E28—E36. http://dx.doi.org/10.1152/ajpendo.1997.273.1.e28.

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Glucose transport in skeletal muscle can be stimulated by insulin and also by contractions and hypoxia. Activation of protein kinase C (PKC) stimulates glucose transport in muscle and other insulin-responsive cells. This study was performed to determine if the diacylglycerol (DAG)/phorbol ester-sensitive PKC isoforms participate in insulin and/or hypoxia-stimulated glucose transport in skeletal muscle. The phorbol ester 12-deoxyphorbol 13-phenylacetate 20-acetate (dPPA) induced a three- to fourfold increase in glucose transport in rat epitrochlearis muscle. The effects of dPPA on glucose transport and on cell surface GLUT-4 were completely additive to the maximal effects of insulin or hypoxia. Phorbol ester treatment induced 5- to 10-fold increases in phosphorylation of the myristoylated alanine-rich C kinase substrate protein in muscle, whereas insulin and hypoxia had negligible effects. Calphostin C, an inhibitor of DAG-sensitive PKC isoforms, decreased glucose transport stimulation by dPPA but not by insulin or hypoxia. These results provide evidence that activation of DAG/phorbol ester-sensitive PKCs is not involved in the pathways by which either insulin or hypoxia stimulates muscle glucose transport. They also show that activation of this group of PKCs increases glucose transport by a mechanism that is independent of and additive to the effects of insulin or hypoxia.

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12

Skalicka-Woźniak, Krystyna, Eleni Melliou, Olga Gortzi, Kazimierz Glowniak e Ioanna B. Chinou. "Chemical Constituents of Lavatera trimestris L. – Antioxidant and Antimicrobial Activities". Zeitschrift für Naturforschung C 62, n. 11-12 (1 dicembre 2007): 797–800. http://dx.doi.org/10.1515/znc-2007-11-1204.

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Nine phenolic compounds, such as cis-/trans-p-coumaric acid, cis-/trans-p-coumaric acid methyl ester, glucose ester of cis-/trans-p-coumaric acid, caffeic acid methyl ester, kaempferol 7-O-β-d-glucoside and kaempferol 3-O-β-d-glucoside, were isolated from Lavatera trimestris flowers by chromatographic techniques and their structures were elucidated by spectral means (NMR). All compounds were tested for their antioxidant activity, while the methanolic extract was tested also for its antimicrobial activity. Also several non-polar constituents have been identified using GC and GC/MS methods. This is the first time that phenolic esters and non-polar constituents were identified in the flowers of L. trimestris L.

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13

Sener, A., I. Conget, J. Rasschaert, V. Leclercq-Meyer, M. L. Villanueva-Penacarrillo, I. Valverde e W. J. Malaisse. "Insulinotropic action of glutamic acid dimethyl ester". American Journal of Physiology-Endocrinology and Metabolism 267, n. 4 (1 ottobre 1994): E573—E584. http://dx.doi.org/10.1152/ajpendo.1994.267.4.e573.

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Glutamic acid dimethyl ester (GME; 3.0–10.0 mM) enhanced insulin release evoked by 6.0–8.3 mM D-glucose, 1.0–10.0 mM L-leucine, or 5.0–10.0 mM 2-amino-bicyclo(2,2,1)heptane-2-carboxylic acid, causing a shift to the left of the sigmoidal relationship between insulin output and D-glucose concentration. In the absence of D-glucose, GME also unmasked the insulinotropic potential of glibenclamide. In islets exposed to L-leucine, the insulinotropic action of GME coincided with an early fall and later increase in 86Rb outflow and augmentation of 45Ca outflow from prelabeled islets. The measurement of O2 uptake, NH4+ output, production of 14CO2 from islets prelabeled with [U-14C]palmitate, generation of 14C-labeled amino acids and 14CO2 from the dimethyl ester of either L-[1-14C]glutamic acid or L-[U-14C]glutamic acid, and D-[2-14C]glucose as well as D-[6-14C]glucose oxidation in the presence or absence of GME indicated that the latter ester was efficiently converted to L-glutamate and its further metabolites. The overall gain in O2 uptake represented the balance between GME oxidation and its sparing action on the catabolism of endogenous fatty acids and exogenous D-glucose. It is proposed that GME might represent a new tool to bypass beta-cell defects in D-glucose transport, phosphorylation, and further metabolism and, hence, to stimulate insulin release in experiments conducted in animal models of non-insulin-dependent diabetes mellitus.

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14

Xu, Xiaoqing, Fatma S. A. Saadeldeen, Lanting Xu, Yingying Zhao, Jinfeng Wei, Hui-Min David Wang, Zhenhua Liu e Wenyi Kang. "The Mechanism of Phillyrin from the Leaves of Forsythia suspensa for Improving Insulin Resistance". BioMed Research International 2019 (2 luglio 2019): 1–7. http://dx.doi.org/10.1155/2019/3176483.

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Three lignans, phillyrin, forsythia ester A, and rosin-β-D-furan glucose, were isolated from Forsythia suspensa which is a famous Traditional Chinese Medicine used for clearing heat and detoxifying, reducing swelling and dispersing knot, and dispersing wind heat. In this study, the effects of phillyrin, forsythia ester A, and rosin-β-D-furan glucose on insulin resistance of 3T3-L1 adipocytes were investigated by the method of glucose oxidase-peroxidase (GOD-POD) and the mechanism was assayed by the method of western blot. The results indicated that phillyrin, forsythia ester A, and rosin-β-D-furan glucose could improve the glucose uptake in 3T3-L1 adipocytes under insulin resistance (IR). Among them, phillyrin showed significant activity in increasing glucose consumption at the concentrations of 100 μM and 200 μM (P < 0.001). The mechanism of improving insulin resistance may be that phillyrin could raise the protein phosphorylation of IRS-1 and Akt and the expression levels of GLUT4 protein.

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15

Era, Manami, Yosuke Matsuo, Yoshinori Saito e Takashi Tanaka. "Production of Ellagitannin Hexahydroxydiphenoyl Ester by Spontaneous Reduction of Dehydrohexa-hydroxydiphenoyl Ester". Molecules 25, n. 5 (26 febbraio 2020): 1051. http://dx.doi.org/10.3390/molecules25051051.

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Amariin is an ellagitannin with two dehydrohexahydroxydiphenoyl (DHHDP) moieties connecting glucose 2,4- and 3,6-hydroxy groups. This tannin is predominant in the young leaves of Triadica sebifera and Carpinus japonica. However, as the leaves grow, the 3,6-DHHDP is converted to its reduced form, the hexahydroxydiphenoyl (HHDP) group, to generate geraniin, a predominant ellagitannin of the matured leaves. The purified amariin is unstable in aqueous solution, and the 3,6-(R)-DHHDP is spontaneously degraded to give HHDP, whereas 2,4-(R)-DHHDP is stable. The driving force of the selective reduction of the 3,6-DHHDP of amariin is shown to be the conformational change of glucose from O,3B to 1C4. Heating geraniin with pyridine affords 2,4-(R)-DHHDP reduction products. Furthermore, the acid hydrolysis of geraniin yields two equivalents of ellagic acid. Although the reaction mechanism is still ambiguous, these results propose an alternative biosynthetic route of the ellagitannin HHDP groups.

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16

Cleland, P. J. F., K. C. Abel, S. Rattigan e M. G. Clark. "Long-term treatment of isolated rat soleus muscle with phorbol ester leads to loss of contraction-induced glucose transport". Biochemical Journal 267, n. 3 (1 maggio 1990): 659–63. http://dx.doi.org/10.1042/bj2670659.

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Muscle contraction involves mobilization of intracellular Ca2+ and is associated with several metabolic adjustments, including increased glucose transport. In the present study isolated rat soleus muscles were exposed to 12-O-tetradecanoylphorbol 13-acetate, and responses to both insulin and contraction in terms of glucose transport were assessed. Muscles treated with this phorbol ester for 12 h showed an increased basal rate of 3-O-methylglucose uptake, and responded partially to insulin but did not respond to contraction. Phorbol-ester-treated and non-treated (vehicle-only) muscles were indistinguishable in terms of pre-contraction content of adenine nucleotide, phosphocreatine, lactate and glycogen, as well as contractile performance and contraction-induced glycogenolysis. Phorbol ester treatment of isolated solei for 12 h resulted in the loss of 90% of protein kinase C activity as determined with histone IIIs as substrate, and 70% as determined by using phorbol ester binding. It is concluded that treatment of solei with phorbol ester gives rise to a marked loss of contraction-induced glucose transport.

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Moheimani, Fatemeh, Joanne T. M. Tan, Bronwyn E. Brown, Alison K. Heather, David M. van Reyk e Michael J. Davies. "Effect of Exposure of Human Monocyte-Derived Macrophages to High, versus Normal, Glucose on Subsequent Lipid Accumulation from Glycated and Acetylated Low-Density Lipoproteins". Experimental Diabetes Research 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/851280.

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During atherosclerosis monocyte-derived macrophages accumulate cholesteryl esters from low-density lipoproteins (LDLs) via lectin-like oxidised LDL receptor-1 (LOX-1) and class AI and AII (SR-AI, SR-AII) and class B (SR-BI, CD36) scavenger receptors. Here we examined the hypothesis that hyperglycaemia may modulate receptor expression and hence lipid accumulation in macrophages. Human monocytes were matured into macrophages in 30 versus 5 mM glucose and receptor expression and lipid accumulation quantified. High glucose elevated LOX1 mRNA, but decreased SR-AI, SR-BI, LDLR, and CD36 mRNA. SR-BI and CD36 protein levels were decreased. Normo- and hyperglycaemic cells accumulated cholesteryl esters from modified LDL to a greater extent than control LDL, but total and individual cholesteryl ester accumulation was not affected by glucose levels. It is concluded that, whilst macrophage scavenger receptor mRNA and protein levels can be modulated by high glucose, these are not key factors in lipid accumulation by human macrophages under the conditions examined.

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Wilson, Alexander E., Hosea D. Matel e Li Tian. "Glucose ester enabled acylation in plant specialized metabolism". Phytochemistry Reviews 15, n. 6 (26 aprile 2016): 1057–74. http://dx.doi.org/10.1007/s11101-016-9467-z.

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19

Malaisse, Willy J., Leonard C. Best, André Herchuelz, Marcia Hiriart, Hassan Jijakli, Marcel M. Kadiata, Elena Larrieta-Carasco et al. "Insulinotropic action of β-l-glucose pentaacetate". American Journal of Physiology-Endocrinology and Metabolism 275, n. 6 (1 dicembre 1998): E993—E1006. http://dx.doi.org/10.1152/ajpendo.1998.275.6.e993.

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The metabolism of β-l-glucose pentaacetate and its interference with the catabolism ofl-[U-14C]glutamine, [U-14C]palmitate,d-[U-14C]glucose, andd-[5-3H]glucose were examined in rat pancreatic islets. Likewise, attention was paid to the effects of this ester on the biosynthesis of islet peptides, the release of insulin from incubated or perifused islets, the functional behavior of individual B cells examined in a reverse hemolytic plaque assay of insulin secretion, adenylate cyclase activity in a membrane-enriched islet subcellular fraction, cAMP production by intact islets, tritiated inositol phosphate production by islets preincubated with myo-[2-3H]inositol, islet cell intracellular pH, 86Rb and 45Ca efflux from prelabeled perifused islets, and electrical activity in single isolated B cells. The results of these experiments were interpreted to indicate that the insulinotropic action of β-l-glucose pentaacetate is not attributable to any nutritional value of the ester but, instead, appears to result from a direct effect of the ester itself on a yet unidentified receptor system, resulting in a decrease in K+ conductance, plasma membrane depolarization, and induction of electrical activity.

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Goggins, Sean, Ellen A. Apsey, Mary F. Mahon e Christopher G. Frost. "Ratiometric electrochemical detection of hydrogen peroxide and glucose". Organic & Biomolecular Chemistry 15, n. 11 (2017): 2459–66. http://dx.doi.org/10.1039/c7ob00211d.

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21

Yoshida, Kentaro, Kazuma Awaji, Seira Shimizu, Miku Iwasaki, Yuki Oide, Megumi Ito, Takenori Dairaku, Tetsuya Ono, Yoshitomo Kashiwagi e Katsuhiko Sato. "Preparation of Microparticles Capable of Glucose-Induced Insulin Release under Physiological Conditions". Polymers 10, n. 10 (18 ottobre 2018): 1164. http://dx.doi.org/10.3390/polym10101164.

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Hydrogen peroxide (H2O2)-sensitive layer-by-layer films were prepared based on combining phenyl boronic acid (PBA)-modified poly(allylamine) (PAH) with shikimic acid (SA)-modified-PAH through boronate ester bonds. These PBA-PAH/SA-PAH multilayer films could be prepared in aqueous solutions at pH 7.4 and 9.0 in the presence of NaCl. It is believed that the electrostatic repulsion between the SA-PAH and PBA-PAH was diminished and the formation of ester bonds between the SA and PBA was promoted in the presence of NaCl. These films readily decomposed in the presence of H2O2 because the boronate ester bonds were cleaved by an oxidation reaction. In addition, SA-PAH/PBA-PAH multilayer films combined with glucose oxidase (GOx) were decomposed in the presence of glucose because GOx catalyzes the oxidation of D-glucose to generate H2O2. The surfaces of CaCO3 microparticles were coated with PAH/GOx/(SA-PAH/PBA-PAH)5 films that absorbed insulin. A 1 mg quantity of these particles released up to 10 μg insulin in the presence 10 mM glucose under physiological conditions.

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22

Best, WM, RW Dunlop, RV Stick e ST White. "All About 3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucosyl Trichloroacetimidate". Australian Journal of Chemistry 47, n. 3 (1994): 433. http://dx.doi.org/10.1071/ch9940433.

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Treatment of 1,3,4,6-tetra-O-acetyl-2-(o-carboxybenzoylamino )-2-deoxy-β-D-glucose with ethyl chloroformate , followed by workup and treatment with methanol, did not give 1,3,4,6-tetra O-acetyl-2-deoxy-2-phthalimido-β-D-glucose as reported in the literature, but rather the methyl ester 1,3,4,6-tetra-O-acetyl-2-deoxy-2-(o- methoxycarbonylbenzoylamino )-β-D-glucose. The formation of this methyl ester is believed to proceed via 1,3,4,6-tetra-O-acetyl-2-deoxy-2- [(3′-oxo-1′,3′-dihydroisobenzofuran-1′-ylidene)amino]-β-D-glucose which was also formed from the amido carboxylic acid by treatment with dicyclohexylcarbodiimide . Optimal procedures are given for the preparation of the title compound 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucosyl trichloroacetimidate.

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23

Agius, Loranne. "Dietary carbohydrate and control of hepatic gene expression: mechanistic links from ATP and phosphate ester homeostasis to the carbohydrate-response element-binding protein". Proceedings of the Nutrition Society 75, n. 1 (12 agosto 2015): 10–18. http://dx.doi.org/10.1017/s0029665115002451.

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Abstract (sommario):

Type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) are associated with elevated hepatic glucose production and fatty acid synthesis (de novolipogenesis (DNL)). High carbohydrate diets also increase hepatic glucose production and lipogenesis. The carbohydrate-response element-binding protein (ChREBP, encoded byMLXIPL) is a transcription factor with a major role in the hepatic response to excess dietary carbohydrate. Because its target genes include pyruvate kinase (PKLR) and enzymes of lipogenesis, it is regarded as a key regulator for conversion of dietary carbohydrate to lipid for energy storage. An alternative hypothesis for ChREBP function is to maintain hepatic ATP homeostasis by restraining the elevation of phosphate ester intermediates in response to elevated glucose. This is supported by the following evidence: (i) A key stimulus for ChREBP activation and induction of its target genes is elevation of phosphate esters; (ii) target genes of ChREBP include key negative regulators of the hexose phosphate ester pool (GCKR,G6PC,SLC37A4) and triose phosphate pool (PKLR); (iii) ChREBP knock-down models have elevated hepatic hexose phosphates and triose phosphates and compromised ATP phosphorylation potential; (iv) gene defects inG6PCandSLC37A4and common variants ofMLXIPL,GCKRandPKLRin man are associated with elevated hepatic uric acid production (a marker of ATP depletion) or raised plasma uric acid levels. It is proposed that compromised hepatic phosphate homeostasis is a contributing factor to the elevated hepatic glucose production and lipogenesis that associate with type 2 diabetes, NAFLD and excess carbohydrate in the diet.

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24

Hingorani, V., e P. Brecher. "Glucose and fatty acid metabolism in normal and diabetic rabbit cerebral microvessels". American Journal of Physiology-Endocrinology and Metabolism 252, n. 5 (1 maggio 1987): E648—E653. http://dx.doi.org/10.1152/ajpendo.1987.252.5.e648.

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Rabbit cerebral microvessels were used to study fatty acid metabolism and its utilization relative to glucose. Microvessels were incubated with either [6-14C]glucose or [1-14C]oleic acid and the incorporation of radioactivity into 14CO2, lactate, triglyceride, cholesterol ester, and phospholipid was determined. The inclusion of 5.5 mM glucose in the incubation mixture reduced oleate oxidation by 50% and increased esterification into both phospholipid and triglyceride. Glucose oxidation to CO2 was reduced by oleate addition, whereas lactate production was unaffected. 2'-Tetradecylglycidic acid, an inhibitor of carnitine acyltransferase I, blocked oleic acid oxidation in the presence and absence of glucose. It did not effect fatty acid esterification when glucose was absent and eliminated the inhibition of oleate on glucose oxidation. Glucose oxidation to 14CO2 was markedly suppressed in microvessels from alloxan-treated diabetic rabbits but lactate formation was unchanged. Fatty acid oxidation to CO2 and incorporation into triglyceride, phospholipid, and cholesterol ester remained unchanged in the diabetic state. The experiments show that both fatty acid and glucose can be used as a fuel source by the cerebral microvessels, and the interactions found between fatty acid and glucose metabolism are similar to the fatty acid-glucose cycle, described previously.

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25

Shimoda, Kei, Manabu Hamada, Hiroshi Yokoi e Hiroki Hamada. "Chemo-Enzymatic Synthesis of Ester-Linked 2-Phenylindole-3-Carboxaldehyde-Monosaccharide Conjugate as Potential Prodrug". Biochemistry Insights 5 (gennaio 2012): BCI.S9961. http://dx.doi.org/10.4137/bci.s9961.

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Abstract (sommario):

Chemo-enzymatic synthesis of ester-linked 2-phenylindole-3-carboxaldehyde-glucose conjugate (2-phenylindole-3-carboxyl-10″-O-β-D-glucosyl ester) was achieved by using plant cell cultures as biocatalysts. The anticancer agent, 2-phenylindole-3-carboxaldehyde, induced apoptosis in cells, whereas 2-phenylindole-3-carboxyl-10″-O-β-D-glucosyl ester showed no cytotoxicity and induced no apoptosis.

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26

Baker, S. Richard, Derek W. Clissold e Alexander McKillop. "Synthesis of leukotriene A4 methyl ester from D-glucose". Tetrahedron Letters 29, n. 9 (gennaio 1988): 991–94. http://dx.doi.org/10.1016/0040-4039(88)85316-4.

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27

Kim, Hyun Woo, Eun Jin Park, Hyo Moon Cho, Jin-Pyo An, Young Won Chin, Jinwoong Kim, Sang Hyun Sung e Won Keun Oh. "Glucose Uptake-Stimulating Galloyl Ester Triterpenoids from Castanopsis sieboldii". Journal of Natural Products 83, n. 10 (23 settembre 2020): 3093–101. http://dx.doi.org/10.1021/acs.jnatprod.0c00645.

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28

Rogers, S., J. R. Gavin e M. R. Hammerman. "Phorbol esters inhibit gluconeogenesis in canine renal proximal tubular segments". American Journal of Physiology-Renal Physiology 249, n. 2 (1 agosto 1985): F256—F262. http://dx.doi.org/10.1152/ajprenal.1985.249.2.f256.

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Abstract (sommario):

Gluconeogenesis is a major metabolic function of the renal proximal tubular cell. To characterize the regulation of this process in proximal tubule, glucose production from gluconeogenic precursors was measured in proximal tubular segments prepared from dog kidney. Production of glucose was a linear function of time for up to 120 min of incubation at 37 degrees C under a variety of conditions. Lowering the pH of incubation media from 7.5 to 7.0 increased glucose synthesis. Production of glucose was inhibited by 3-mercaptopicolinate. Incubation of proximal tubular segments with insulin diminished synthesis of glucose. Incubation of segments with tumor-promoting phorbol esters, 12-O-tetradecanoylphorbol-13-acetate or phorbol 12,13-dibutyrate, resulted in decreased production of glucose. This effect was not observed following incubation with the inactive phorbol ester 4 alpha-phorbol. Changes in glucose synthesis could not be attributed to alterations in cell viability or in rates of glucose oxidation induced by experimental maneuvers. Our findings confirm the usefulness of proximal tubular segments for characterization of metabolic processes in this portion of the nephron. The experimental results are consistent with a role for protein kinase C in the control of gluconeogenesis in proximal tubule.

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29

Wei, Chao, Yin Zhen Wang, Wei Yan, Ping Jia Yao e Yuan An Wei. "Enzymatic and Chemical Synthesis and Characterization of Poly-6-O-(10-undecylenoyl) D-Glucose". Advanced Materials Research 550-553 (luglio 2012): 787–91. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.787.

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Abstract (sommario):

Immobilized lipase Novozym-435 catalyzed regioselective synthesis of glucose and undecylenic acid(UA) to produce glucose mono-ester in Organic solvents was investigated. Reactionconditions were tested in order to produce the mono-ester more rapidly and in higher yield, the optimal conditions were obtained as: temperature at 50°C,mole ratio of glucose toUA of 1:2,concentration of molecular sieves and enzyme used as 0.56mg/mL and 10mg/mL respectively . After the reaction, product was purified, and characterized by MS and 13C NMR spectroscopy, and determined as 6-O-(10-undercylenoyl)-D-glucose, The product was used as the starting material, K2S2O8 as a chemical initiator, to polymerize and form the sugar-containing polymer, which could be used for medicine release agent and other application of biological materials.

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30

Goldberg, Joel S. "Low Molecular Weight Opioid Peptide Esters Could be Developed as a New Class of Analgesics". Perspectives in Medicinal Chemistry 5 (gennaio 2011): PMC.S6803. http://dx.doi.org/10.4137/pmc.s6803.

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Abstract (sommario):

Low molecular weight opioid peptide esters (OPE) could become a class of analgesics with different side effect profiles than current opiates. OPE may have sufficient plasma stability to cross the blood brain barrier (BBB), undergo ester hydrolysis and produce analgesia. OPE of dipeptides, tyr-pro and tyr-gly conjugated to ethanol have a structure similar to the anesthestic agent, etomidate. Based upon the analgesic activity of dipeptide opioids, Lipinski's criteria, and permeability of select GABA esters to cross the BBB, opioid peptides (OP) conjugated to ethanol, cholesterol or 3-glucose are lead recommendations. Preliminary animal data suggests that tyr-pro-ethyl ester crosses the BBB and unexpectedly produces hyperalgesia. Currently, there are no approved OP analgesics available for clinical use. Clinical trials of good manufacturing practice OP administered to patients suffering from chronic pain with indwelling intrathecal pumps could resolve the issue that OP may be superior to opiates and may redirect research.

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31

Snoch, Wojciech, Karolina Stępień, Justyna Prajsnar, Jakub Staroń, Maciej Szaleniec e Maciej Guzik. "Influence of Chemical Modifications of Polyhydroxyalkanoate-Derived Fatty Acids on Their Antimicrobial Properties". Catalysts 9, n. 6 (5 giugno 2019): 510. http://dx.doi.org/10.3390/catal9060510.

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Abstract (sommario):

Sugar esters are bioactive compounds derived from renewable resources. They consist of a sugar moiety with attached non-polar part – usually a fatty acid. These compounds find uses in cosmetic, food and pharmaceutical industries as surfactants due to their physicochemical and antimicrobial activities. In this study we have produced fatty acids for sugar ester synthesis from bacterially derived polyesters, namely polyhydroxyalkanoates (PHAs). We have developed methodology to decorate PHA monomers with a fluorinated moiety. With aid of biocatalysis a series of glucose esters was created with unmodified and modified PHA monomers. All synthesised compounds showed moderate antimicrobial activity.

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32

Picton, Sally F., Peter R. Flatt e Neville H. McClenaghan. "Differential Acute and Long Term Actions of Succinic Acid Monomethyl Ester Exposure on Insulin-Secreting BRIN-BD11 Cells". International Journal of Experimental Diabetes Research 2, n. 1 (2001): 19–27. http://dx.doi.org/10.1155/edr.2001.19.

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Abstract (sommario):

Esters of succinic acid are potent insulin secretagogues, and have been proposed as novel antidiabetic agents for type 2 diabetes. This study examines the effects of acute and chronic exposure to succinic acid monomethyl ester (SAM) on insulin secretion, glucose metabolism and pancreatic beta cell function using the BRIN-BD11 cell line. SAM stimulated insulin release in a dose-dependent manner at both non-stimulatory (1.1mM) and stimulatory (16.7mM) glucose. The depolarizing actions of arginine also stimulated a significant increase in SAM-induced insulin release but 2-ketoisocaproic acid (KIC) inhibited SAM induced insulin secretion indicating a possible competition between the preferential oxidative metabolism of these two agents. Prolonged (18hour) exposure to SAM revealed decreases in the insulin-secretory responses to glucose, KIC, glyceraldehyde and alanine. Furthermore, SAM diminished the effects of nonmetabolized secretagogues arginine and 3-isobutyl-1-methylxanthine (IBMX). While the ability of BRIN-BD11 cells to oxidise glucose was unaffected by SAM culture, glucose utilization was substantially reduced. Collectively, these data suggest that while SAM may enhance the secretory potential of non-metabolized secretagogues, it may also serve as a preferential metabolic fuel in preference to other important physiological nutrients and compromise pancreatic beta cell function following prolonged exposure.

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33

Mühlbacher, C., E. Karnieli, P. Schaff, B. Obermaier, J. Mushack, E. Rattenhuber e H. U. Häring. "Phorbol esters imitate in rat fat-cells the full effect of insulin on glucose-carrier translocation, but not on 3-O-methylglucose-transport activity". Biochemical Journal 249, n. 3 (1 febbraio 1988): 865–70. http://dx.doi.org/10.1042/bj2490865.

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Abstract (sommario):

Tumour-promoting phorbol esters have insulin-like effects on glucose transport and lipogenesis in adipocytes and myocytes. It is believed that insulin activates the glucose-transport system through translocation of glucose transporters from subcellular membranes to the plasma membrane. The aim of the present study was to investigate if phorbol esters act through the same mechanism as insulin on glucose-transport activity of rat adipocytes. We compared the effects of the tumour-promoting phorbol ester tetradecanoylphorbol acetate (TPA) and of insulin on 3-O-methylglucose transport and on the distribution of D-glucose-inhibitable cytochalasin-B binding sites in isolated rat adipocytes. Insulin (100 mu units/ml) stimulated 3-O-methylglucose uptake 9-fold, whereas TPA (1 nM) stimulated the uptake only 3-fold (mean values of five experiments, given as percentage of equilibrium reached after 4 s: basal 7 +/- 1.3%, insulin 60 +/- 3.1%, TPA 22 +/- 2.3%). In contrast, both agents stimulated glucose-transporter translocation to the same extent [cytochalasin B-binding sites (pmol/mg of protein; n = 7): plasma membranes, basal 6.2 +/- 1.0, insulin 13.4 +/- 2.0, TPA 12.7 +/- 2.7; low-density membranes, basal 12.8 +/- 2.1, insulin 6.3 +/- 0.9, TPA 8.9 +/- 0.7; high-density membranes, 6.9 +/- 1.1; insulin 12.5 +/- 1.0, TPA 8.1 +/- 0.9]. We conclude from these data: (1) TPA stimulates glucose transport in fat-cells by stimulation of glucose-carrier translocation; (2) insulin and TPA stimulate the carrier translocation to the same extent, whereas the stimulation of glucose uptake is 3-fold higher with insulin, suggesting that the stimulatory effect of insulin on glucose-transport activity involves other mechanisms in addition to carrier translocation.

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34

Nasution, Rosnani, Chairani Nur Fitrah, Hira Helwati, Murniana Murniana, Bastian Arifin, Cutchamzurni Cutchamzurni, Yose Rizal e Marianne Marianne. "ANTIDIABETES ACTIVITIES EXTRACT HEXANE FROM THE PEELS OF ARTOCARPUS CAMANSI BLANCO FRUIT". Asian Journal of Pharmaceutical and Clinical Research 11, n. 13 (26 aprile 2018): 12. http://dx.doi.org/10.22159/ajpcr.2018.v11s1.26554.

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Abstract (sommario):

Objective: The purpose of this research is to know the chemical compound from the n-hexane extract of Kulu (Artocarpus camansi Blanco) fruit peels and to know its antidiabetes activity against male Swiss Webster mice.Methods: Samples were macerated with n-hexane solvent, then the extracts were obtained, was characterization with gas chromatography-mass spectrometry (GC-MS), and then the extract separated by column chromatography. The results obtained were tested by antidiabetes action with glucose tolerance method.Results: Anti-diabetic activity test result showed that the most active sample to decrease the blood glucose of mice was n-hexane crude extract, at minute 90th, activeness was 65.59%, compared to glibenclamide, then group of fraction A, at minute 90th, activeness 65.58% compared glibenclamide, whereas isolate D11, its activity is 60.11% and 60.12%, at minute 60th and 90 min compared to glibenclamide. Concentrated extracts were characterized by GC-MS, shows the major compounds are hexadecanoic acid methyl ester (30.14%), 9,12-octadecadienoyl chloride, (Z, Z) - (8.44%) and 9-octadecenoic acid, methyl ester (30,91%) also were obtained a compound like an β-amyrin acetate.Conclusion: The most active sample to decrease the blood glucose of mice was n-hexane crude extract, and the major compounds are hexadecanoic acid methyl ester (30.14%), 9,12-octadecadienoyl chloride, (Z, Z) - (8.44%) and 9-octadecenoic acid, methyl ester (30.91%).

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35

Inaba, H., e J. P. Filkins. "Augmentation of endotoxic lethality and glucose dyshomeostasis by phorbol ester". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 260, n. 3 (1 marzo 1991): R494—R502. http://dx.doi.org/10.1152/ajpregu.1991.260.3.r494.

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Abstract (sommario):

To investigate the role of protein kinase C (PKC) activation in the pathogenesis of endotoxin (ETX) shock, the in vivo effects of phorbol 12-myristate 13-acetate (PMA) on ETX-induced lethality and glucose dyshomeostasis were determined. Fed rats (300-400 g) were treated intravenously with incremental doses of Salmonella enteritidis ETX and either the vehicle, 110 mg/kg ip dimethyl sulfoxide (DMSO), or 0.5 mg/kg ip PMA dissolved in DMSO. PMA significantly increased ETX-induced lethality to doses of 1.0-20 mg/kg. PMA augmented the initial hyperglycemia, late hypoglycemia, and hyperlactacidemia after 1 mg/kg iv ETX to rats anesthetized with pentobarbital sodium. In contrast, 4 alpha-phorbol, a phorbol derivative that does not activate PKC, had no effect on either lethality or the glucose and lactate responses. Hyperinsulinemia after 1 mg/kg iv ETX was prolonged by PMA but not by 4 alpha-phorbol. Insulin tolerance testing (0.5 U/kg iv) produced an exaggerated hypoglycemic response in PMA-treated endotoxic (0.33 mg/kg) rats. Glucose tolerance to 1.2 g/kg iv was increased by ETX and PMA attenuated the increased tolerance. Thus PKC activation may be involved in the pathogenesis of lethal endotoxicosis and associated glucose dyshomeostasis.

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36

Balsevich, J., G. Bishop, S. L. Jacques, L. R. Hogge, D. J. H. Olson e N. Laganière. "Preparation and analysis of some acetosugar esters of abscisic acid and derivatives". Canadian Journal of Chemistry 74, n. 2 (1 febbraio 1996): 238–45. http://dx.doi.org/10.1139/v96-027.

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Abstract (sommario):

Racemic abscisic acid (ABA), the cis and trans 1′, 4′-diols (ABA diols) derived from ABA by reduction of the 4′ ketone, and the corresponding 4′-O-acetates were converted into various acetosugar esters by reaction of their cesium salts with the 1-chloroacetosugars derived from glucose, galactose, lactose, and maltose. Analytical separations of the acetosugar esters using high-performance liquid chromatography (LC) on reverse-phase columns were developed. Continuous flow secondary ion mass spectra (CFSIMS) of the various acetosugar esters were obtained and an LC/CFSIMS protocol employing multiple reaction monitoring was used to detect ABA acetoglucose ester in an acetylated extract obtained from plant cells that had been treated with ABA. Key words: abscisic acid, acetosugar esters, synthesis, chromatography, mass spectrometry.

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37

Gibbs, E. M., D. M. Calderhead, G. D. Holman e G. W. Gould. "Phorbol ester only partially mimics the effects of insulin on glucose transport and glucose-transporter distribution in 3T3-L1 adipocytes". Biochemical Journal 275, n. 1 (1 aprile 1991): 145–50. http://dx.doi.org/10.1042/bj2750145.

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Abstract (sommario):

We examined the effects of the phorbol ester phorbol 12-myristate 13-acetate (PMA) on the rate of hexose transport into 3T3-L1 adipocytes. Exposure of adipocytes to PMA (1 microM) for 60 min results in a 1.7-2.5-fold increase in the rate of hexose transport. This effect was mediated by translocation of two isoforms of glucose transporters to the plasma membrane, as determined by labelling in situ, photoaffinity labelling with a membrane-impermeant glucose analogue, and by immunoblotting of subcellular fractions. The PMA-induced stimulation of both transport and transporter translocation was substantially less than that induced by insulin in this cell line; the PMA-induced increase in plasma-membrane GLUT 1 and GLUT 4 transporter isoforms was only about 40% and 10% respectively of that induced by insulin. We suggest that the stimulation of transport by insulin and PMA occurs via different mechanisms, which is manifested by the ability of insulin to induce a much greater increase in the plasma-membrane content of GLUT 4 compared with the phorbol ester.

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38

Ganske, Franka, e Uwe T. Bornscheuer. "Lipase-Catalyzed Glucose Fatty Acid Ester Synthesis in Ionic Liquids". Organic Letters 7, n. 14 (luglio 2005): 3097–98. http://dx.doi.org/10.1021/ol0511169.

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39

Lee, Chen-Chang, Yemin Liu e Theresa M. Reineke. "Glucose-Based Poly(ester amines): Synthesis, Degradation, and Biological Delivery". ACS Macro Letters 1, n. 12 (26 novembre 2012): 1388–92. http://dx.doi.org/10.1021/mz300505t.

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40

Ha, Sung Ho, Nguyen Minh Hiep, Sang Hyun Lee e Yoon-Mo Koo. "Optimization of lipase-catalyzed glucose ester synthesis in ionic liquids". Bioprocess and Biosystems Engineering 33, n. 1 (13 agosto 2009): 63–70. http://dx.doi.org/10.1007/s00449-009-0363-4.

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41

Wang, Wenjing, Dong An e Zhiwen Ye. "Synthesis and properties of amino acid glucose ester dimeric surfactants". Journal of Dispersion Science and Technology 39, n. 2 (16 maggio 2017): 292–97. http://dx.doi.org/10.1080/01932691.2017.1316204.

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42

Fulceri, R., A. Gamberucci, H. M. Scott, R. Giunti, A. Burchell e A. Benedetti. "Fatty acyl-CoA esters inhibit glucose-6-phosphatase in rat liver microsomes". Biochemical Journal 307, n. 2 (15 aprile 1995): 391–97. http://dx.doi.org/10.1042/bj3070391.

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Abstract (sommario):

In native rat liver microsomes glucose 6-phosphatase activity is dependent not only on the activity of the glucose-6-phosphatase enzyme (which is lumenal) but also on the transport of glucose-6-phosphate, phosphate and glucose through the respective translocases T1, T2 and T3. By using enzymic assay techniques, palmitoyl-CoA or CoA was found to inhibit glucose-6-phosphatase activity in intact microsomes. The effect of CoA required ATP and fatty acids to form fatty acyl esters. Increasing concentrations (2-50 microM) of CoA (plus ATP and 20 microM added palmitic acid) or of palmitoyl-CoA progressively decreased glucose-6-phosphatase activity to 50% of the control value. The inhibition lowered the Vmax without significantly changing the Km. A non-hydrolysable analogue of palmitoyl-CoA also inhibited, demonstrating that binding of palmitoyl-CoA rather than hydrolysis produces the inhibition. Light-scattering measurements of osmotically induced changes in the size of rat liver microsomal vesicles pre-equilibrated in a low-osmolality buffer demonstrated that palmitoyl-CoA alone or CoA plus ATP and palmitic acid altered the microsomal permeability to glucose 6-phosphate, but not to glucose or phosphate, indicating that T1 is the site of palmitoyl-CoA binding and inhibition of glucose-6-phosphatase activity in native microsomes. The type of inhibition found suggests that liver microsomes may comprise vesicles heterogeneous with respect to glucose-6-phosphate translocase(s), i.e. sensitive or insensitive to fatty acid ester inhibition.

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43

Buzatu, Alina Ramona, August E. Frissen, Lambertus A. M. van den Broek, Anamaria Todea, Marilena Motoc e Carmen Gabriela Boeriu. "Chemoenzymatic Synthesis of New Aromatic Esters of Mono- and Oligosaccharides". Processes 8, n. 12 (11 dicembre 2020): 1638. http://dx.doi.org/10.3390/pr8121638.

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Abstract (sommario):

An efficient and convenient chemoenzymatic route for the synthesis of novel phenolic mono-, di- and oligosaccharide esters is described. Acetal derivatives of glucose, sucrose, lactose and inulin were obtained by chemical synthesis. The fully characterized pure sugar acetals were subjected to enzymatic esterification with 3-(4-hydroxyphenyl) propionic acid (HPPA) in the presence of Novozyme 435 lipase as a biocatalyst. The aromatic esters of alkyl glycosides and glucose acetal were obtained with good esterification yields, characterized by mass spectrometry (MALDI-TOF MS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR). The synthesis of aromatic esters of disaccharide acetals was successful only for the enzymatic esterification of sucrose acetal. The new chemoenzymatic route allowed the synthesis of novel aromatic esters of inulin as the inulin monoacetal monoester and diester and the inulin diacetal monoester with a polymerization degree of two, as well as the inulin monoacetal monoester with a degree of polymerization of three, were obtained by enzymatic acylation of inulin acetals with HPPA. These compounds could represent a new class of sugar ester surfactants with enhanced bioactivity, antioxidative and antimicrobial properties and with potential application in drug delivery systems.

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44

Chan, C. B. "Glucokinase activity in isolated islets from obese fa/fa Zucker rats". Biochemical Journal 295, n. 3 (1 novembre 1993): 673–77. http://dx.doi.org/10.1042/bj2950673.

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Abstract (sommario):

Glucokinase (EC 2.7.1.2) activity of B-cells was measured in extracted pancreatic islets isolated from lean and obese fa/fa Zucker rats and maintained in primary culture overnight. Formation of [14C]glucose phosphoric esters from D-[U-14C]glucose was measured in the presence of unlabelled glucose from 0.05 to 0.50 mM for hexokinase (EC 2.7.1.1) activity, and 8.0-16.0 mM unlabelled glucose for glucokinase activity. Eadie-Hofstee analysis revealed that hexokinase kinetic parameters (Vmax and Km) for [14C]glucose phosphoric ester formation were similar in lean- and fa/fa-rat islets. For glucokinase, there was no difference in Vmax. between phenotypes. A non-significant tendency to increased sensitivity to glucose was noted in the fa/fa-rat islets (P = 0.13). In lean-rat islets, the glucokinase inhibitor mannoheptulose (3 mM) decreased Vmax. by 80% and increased the apparent Km from 3.3 +/- 0.7 mM to 12.2 +/- 2.0 mM (P < 0.05). There was no difference in Km or Vmax. in mannoheptulose-treated versus control islets from fa/fa rats. This lack of effect was consistent with reported effects of mannoheptulose on insulin secretion from fa/fa-rat islets [Chan, MacPhail and Mitton (1993) Can. J. Physiol. Pharmacol. 71, 34-39]. The data from glucose and mannoheptulose experiments support the hypothesis that glucokinase function is altered in fa/fa Zucker rats and may contribute to fasting hyperinsulinaemia in vivo in these animals.

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45

Chu, Shaoyou, e H. Glenn Bohlen. "High concentration of glucose inhibits glomerular endothelial eNOS through a PKC mechanism". American Journal of Physiology-Renal Physiology 287, n. 3 (settembre 2004): F384—F392. http://dx.doi.org/10.1152/ajprenal.00006.2004.

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Abstract (sommario):

Kidney glomeruli are important targets of diabetic nephropathy. We hypothesized a high concentration of glucose could suppress glomerular endothelial nitric oxide synthase (eNOS) by a protein kinase C (PKC) mechanism, as has been found in other tissues. Mouse kidney slices (150–200 μm) were bathed in Hanks' solution with 100 μM l-arginine and exposed to either 5 or 20–30 mM d-glucose. Immunofluorescence identified only eNOS in normal mouse glomeruli. Measurements of glomerular NO concentration with NO-sensitive fluorescent dye (4,5-diaminofluorescein diacetate) using confocal microscopy and NO-sensitive microelectrodes verified that resting glomeruli had active production of NO that was inhibited by NG-nitro-l-arginine methyl ester. High-concentration (20–30 mM) d-glucose inhibited 60–70% of the NO production within 15–30 min; l-glucose at the same concentration did not have any effect. Inhibition of PKC-β with 100 nM ruboxistaurin prevented eNOS suppression in high-glucose media. Activation of PKC with 100 nM phorbol ester also suppressed the glomerular NO concentration. We concluded that eNOS in the renal glomerular capillary endothelial cells is suppressed by activity of PKC at high-glucose concentrations comparable to those in diabetic animals and humans. The consequence is a rapid decline in the generation of NO in the glomerular endothelial cells in the presence of a high concentration of glucose.

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46

Kongdin, Manatchanok, Bancha Mahong, Sang-Kyu Lee, Su-Hyeon Shim, Jong-Seong Jeon e James R. Ketudat Cairns. "Action of Multiple Rice β-Glucosidases on Abscisic Acid Glucose Ester". International Journal of Molecular Sciences 22, n. 14 (15 luglio 2021): 7593. http://dx.doi.org/10.3390/ijms22147593.

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Conjugation of phytohormones with glucose is a means of modulating their activities, which can be rapidly reversed by the action of β-glucosidases. Evaluation of previously characterized recombinant rice β-glucosidases found that nearly all could hydrolyze abscisic acid glucose ester (ABA-GE). Os4BGlu12 and Os4BGlu13, which are known to act on other phytohormones, had the highest activity. We expressed Os4BGlu12, Os4BGlu13 and other members of a highly similar rice chromosome 4 gene cluster (Os4BGlu9, Os4BGlu10 and Os4BGlu11) in transgenic Arabidopsis. Extracts of transgenic lines expressing each of the five genes had higher β-glucosidase activities on ABA-GE and gibberellin A4 glucose ester (GA4-GE). The β-glucosidase expression lines exhibited longer root and shoot lengths than control plants in response to salt and drought stress. Fusions of each of these proteins with green fluorescent protein localized near the plasma membrane and in the apoplast in tobacco leaf epithelial cells. The action of these extracellular β-glucosidases on multiple phytohormones suggests they may modulate the interactions between these phytohormones.

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47

Pace, C. S., e K. T. Goldsmith. "Action of a phorbol ester on B-cells: potentiation of stimulant-induced electrical activity". American Journal of Physiology-Cell Physiology 248, n. 5 (1 maggio 1985): C527—C534. http://dx.doi.org/10.1152/ajpcell.1985.248.5.c527.

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The possible role of protein kinase c in regulating the electrical events in the B-cell plasma membrane was examined by using the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), a known activator of this enzyme. TPA has been found to enhance glucose- and sulfonylurea-induced insulin secretion with little or no effect on the fluxes of 86Rb+ or 45Ca2+ across the plasma membrane. TPA, 0.2 microM, did not influence the membrane potential from 0 to 5.6 mM glucose but increased by two- to threefold the fraction of the plateau phase of the oscillatory electrical activity induced by 7.0-11.1 mM glucose. This effect of TPA was completely blocked by 0.5 mM spermidine, an inhibitor of protein kinase c. However, spermidine had no influence on the electrical activity elicited by glucose alone. Glyburide, 10 nM, initiated slow depolarization and constant spike activity after about 18 and 25 min, respectively. TPA or 2.8 mM glucose reduced the lag period for glyburide to elicit an electrical response by about 75%. The duration of the spikes was increased two- to threefold by the presence of glucose or TPA with glyburide. There were also characteristic differences in the shape of the spikes under each experimental condition. Spermidine inhibited the influence of glucose, but not TPA, on the glyburide-induced electrical response. These results indicate that TPA may influence stimulant-induced electrical events via protein kinase c or by directly altering the ionic permeability of the plasma membrane.

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48

Haliński, Łukasz P., e Piotr Stepnowski. "GC-MS and MALDI-TOF MS Profi ling of Sucrose Esters from Nicotiana tabacum and N. rustica". Zeitschrift für Naturforschung C 68, n. 5-6 (1 giugno 2013): 210–22. http://dx.doi.org/10.1515/znc-2013-5-607.

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Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDITOF MS) has been applied for the first time to the analysis of the sucrose esters from the surface of Nicotiana L. leaves. The profiles obtained for the model plant N. tabacum were similar to those from the gas chromatography-flame ionization detector (GC-FID) analysis. The most reproducible results were obtained using a dihydroxybenzoic acid (DHB) matrix. The main advantage of this method is that crude plant extracts can be analysed without sample clean-up. GC-MS analysis of Aztec tobacco (N. rustica) extracts revealed the presence of three types of sucrose esters. All identified compounds had three C4 − C8 acyl chains substituting the glucose moiety, while the fructose part of the molecule was substituted with 0, 1, or 2 acetyl groups. MALDI-TOF MS analysis of the sucrose ester fraction revealed the presence of compounds not eluting from a GC column. Combining the data from both GC-MS and MALDI-TOF MS experiments, we obtained a full sucrose ester profile, which is based on the molecular weight of the compounds and on the number of acyl chains in the molecule.

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Bhattacharjee, Sreebash Chandra, Md H. O. Roshid, Md Atiquel Islam Chowdhury e Mohammed Belal Hossain. "DFT Based Comparative Studies of Some Glucofuranose and Glucopyranoside Esters and Ethers". Journal of Applied Science & Process Engineering 8, n. 2 (31 ottobre 2021): 881–91. http://dx.doi.org/10.33736/jaspe.3786.2021.

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Carbohydrate-based molecular scaffolding received significant interest due to its impact on the drug discovery and development in synthetic carbohydrate chemistry during the last couple of decades. In this respect, four glucose compounds in the furanose and pyranose forms with ester and ether functionality were selected for their structural, thermodynamic and chemical reactivity studies. PASS predication indicated that the glucose in the six-membered pyranose form was more prone to biological properties compared to their five-membered furanose form. Also, in the pyranose form acetate ester (3) had more potentiality than the ethyl ether (4). The HOMO-LUMO energy gaps were almost similar for both monosubstituted furanose and pyranose glucose indicating their almost similar reactivities. It was also inferred that these 6-O-substituted compounds followed Lipinski’s rule with the acceptable range of ADMET levels, and hence, safe from lethal proarrhythmic risks. Hopefully, these results can be used in the near future for their probable pharmaceutical use without any remarkable toxicity.

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50

Quentmeier, A., H. Daneschmand, H. Klein, K. Unthan-Fechner e I. Probst. "Insulin-mimetic actions of phorbol ester in cultured adult rat hepatocytes. Lack of phorbol-ester-elicited inhibition of the insulin signal". Biochemical Journal 289, n. 2 (15 gennaio 1993): 549–55. http://dx.doi.org/10.1042/bj2890549.

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The actions of the phorbol ester phorbol 12-myristate 13-acetate (PMA) on glucose metabolism, amino acid transport and enzyme inductions were studied in primary cultures of adult-rat hepatocytes and compared with the effects of insulin. PMA and insulin stimulated glycolysis 5- and 7-fold respectively. The half-maximal effective dose of PMA was 60 nM. Stimulation of glycolysis was accompanied by an insulin- or PMA-dependent and okadaic acid-sensitive activation of 6-phosphofructo-2-kinase and pyruvate kinase, as well as by an increase in fructose 2,6-bisphosphate. Glucose production from glycogen was decreased to 50% by PMA and to 15% by insulin, whereas glycogen synthesis was stimulated 2- and 7-fold respectively. PMA also increased aminoisobutyrate uptake, induced ornithine decarboxylase and counteracted the glucagon-dependent induction of phosphoenolpyruvate carboxykinase. PMA strongly antagonized the hormonal activation of glycogen synthesis, but all other insulin actions assayed were not decreased by the phorbol ester. Whereas additive effects of PMA and insulin were not detected, PMA and a simultaneous increase in the glucose concentration had additive effects on glycolysis and glycogen metabolism. Cell exposure to insulin resulted in receptor autophosphorylation and a more than 10-fold activation of the receptor tyrosine kinase. PMA did not alter these effects, and also had no effect on the receptor phosphorylation status in the absence of insulin. Long-term (15 h) pretreatment of the cells with PMA abolished all PMA effects, but not the insulin effects. It is concluded that PMA does not generally antagonize the action of insulin in differentiated adult hepatocytes, and that insulin and PMA may use related signal-transduction pathways.

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