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Diwakar Z. Shende - One of the best experts on this subject based on the ideXlab platform.
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Natural Nontoxic Solvents for Recovery of Picolinic Acid by Reactive Extraction
Industrial & Engineering Chemistry Research, 2011Co-Authors: Mangesh D. Waghmare, Kailas L. Wasewar, Shriram S. Sonawane, Diwakar Z. ShendeAbstract:Pyridine carboxylic Acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic Acid, also known as Picolinic Acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic Acid is an advantageous alternative for the production of Picolinic Acid. Reactive extraction is a promising method to recover carboxylic Acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover Acid efficiently. The present paper focuses on the reactive extraction of Picolinic Acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio (
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natural nontoxic solvents for recovery of Picolinic Acid by reactive extraction
Industrial & Engineering Chemistry Research, 2011Co-Authors: Mangesh D. Waghmare, Kailas L. Wasewar, Shriram S. Sonawane, Diwakar Z. ShendeAbstract:Pyridine carboxylic Acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic Acid, also known as Picolinic Acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic Acid is an advantageous alternative for the production of Picolinic Acid. Reactive extraction is a promising method to recover carboxylic Acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover Acid efficiently. The present paper focuses on the reactive extraction of Picolinic Acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio (<0.5), degree of extraction (0.65 to 42.9%...
Peter Steinberger - One of the best experts on this subject based on the ideXlab platform.
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the tryptophan metabolite Picolinic Acid suppresses proliferation and metabolic activity of cd4 t cells and inhibits c myc activation
Journal of Leukocyte Biology, 2016Co-Authors: Johanna Prodinger, Lisa J. Loacker, Ralf Schmidt, Franz Ratzinger, Georg Greiner, Nadine Witzeneder, Gregor Hoermann, Sabrina Jutz, Winfried F. Pickl, Peter SteinbergerAbstract:Tryptophan metabolites, including kynurenine, 3-hydroxyanthranilic Acid, and Picolinic Acid, are key mediators of immunosuppression by cells expressing the tryptophan-catabolizing enzyme indoleamine2,3-dioxygenase. In this study, we assessed the influence of Picolinic Acid on cell viability and effector functions of CD4(+)T cells following in vitro activation with agonistic anti-CD3/anti-CD28 antibodies. In contrast to kynurenine and 3-hydroxyanthranilic Acid, exposure of T cells with Picolinic Acid did not affect cell viability, whereas proliferation and metabolic activity were suppressed in a dose-dependent manner. On the other hand, cytokine secretion and up-regulation of cell surface activation markers were not or only weakly inhibited by Picolinic Acid. Picolinic Acid exposure induced a state of deep anergy that could not be overcome by the addition of exogenous IL-2 and inhibited Th cell polarization. On the molecular level, important upstream signaling molecules, such as the MAPKs ERK and p38 and the mammalian target of rapamycin target protein S6 ribosomal protein, were not affected by Picolinic Acid. Likewise, NFAT, NF-κB, and AP-1 promoter activity in Jurkat T cells was not influenced by exposure to Picolinic Acid. Whereas transcriptional levels of v-myc avian myelocytomatosis viral oncogene homolog were not affected by Picolinic Acid, phosphorylation at Ser62 was strongly reduced in Picolinic Acid-exposed T cells following activation. In conclusion, Picolinic Acid mediates a unique immunosuppressive program in T cells, mainly inhibiting cell cycle and metabolic activity, while leaving other effector functions intact. These functional features are accompanied by reduced phosphorylation of v-myc avian myelocytomatosis viral oncogene homolog. It remains to be determined whether this effect is mediated by direct inhibition of ERK activity or whether indirect mechanisms apply.
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The tryptophan metabolite Picolinic Acid suppresses proliferation and metabolic activity of CD4+ T cells and inhibits c‐Myc activation
Journal of leukocyte biology, 2015Co-Authors: Johanna Prodinger, Lisa J. Loacker, Ralf Schmidt, Franz Ratzinger, Georg Greiner, Nadine Witzeneder, Gregor Hoermann, Sabrina Jutz, Winfried F. Pickl, Peter SteinbergerAbstract:Tryptophan metabolites, including kynurenine, 3-hydroxyanthranilic Acid, and Picolinic Acid, are key mediators of immunosuppression by cells expressing the tryptophan-catabolizing enzyme indoleamine2,3-dioxygenase. In this study, we assessed the influence of Picolinic Acid on cell viability and effector functions of CD4(+)T cells following in vitro activation with agonistic anti-CD3/anti-CD28 antibodies. In contrast to kynurenine and 3-hydroxyanthranilic Acid, exposure of T cells with Picolinic Acid did not affect cell viability, whereas proliferation and metabolic activity were suppressed in a dose-dependent manner. On the other hand, cytokine secretion and up-regulation of cell surface activation markers were not or only weakly inhibited by Picolinic Acid. Picolinic Acid exposure induced a state of deep anergy that could not be overcome by the addition of exogenous IL-2 and inhibited Th cell polarization. On the molecular level, important upstream signaling molecules, such as the MAPKs ERK and p38 and the mammalian target of rapamycin target protein S6 ribosomal protein, were not affected by Picolinic Acid. Likewise, NFAT, NF-κB, and AP-1 promoter activity in Jurkat T cells was not influenced by exposure to Picolinic Acid. Whereas transcriptional levels of v-myc avian myelocytomatosis viral oncogene homolog were not affected by Picolinic Acid, phosphorylation at Ser62 was strongly reduced in Picolinic Acid-exposed T cells following activation. In conclusion, Picolinic Acid mediates a unique immunosuppressive program in T cells, mainly inhibiting cell cycle and metabolic activity, while leaving other effector functions intact. These functional features are accompanied by reduced phosphorylation of v-myc avian myelocytomatosis viral oncogene homolog. It remains to be determined whether this effect is mediated by direct inhibition of ERK activity or whether indirect mechanisms apply.
Milan J Anadkat - One of the best experts on this subject based on the ideXlab platform.
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a pilot study of the safety and efficacy of Picolinic Acid gel in the treatment of acne vulgaris
British Journal of Dermatology, 2007Co-Authors: Michael P Heffernan, Matthew M Nelson, Milan J AnadkatAbstract:Summary Background Cost limitations, adverse effects or lack of efficacy limit the use of current topical therapies in mild to moderate acne vulgaris. Objectives To determine the safety and efficacy of Picolinic Acid, a novel zinc finger therapy, in the treatment of mild to moderate acne vulgaris. Methods Twenty subjects with mild to moderate acne vulgaris were treated at our centre during an open-label study with 10% Picolinic Acid gel (PCL-016) twice daily to the face over 12 weeks. Results Fifteen patients completed the 12-week open-label study. A reduction of 58·2% (P < 0·001) in mean total lesion count, 55·5% (P < 0·001) in mean inflammatory lesion count and 59·7% (P < 0·005) in noninflammatory lesion count was seen in this population. No serious adverse events or clinically significant changes in laboratory values were noted. Conclusions Results from this study suggest that 10% Picolinic Acid gel applied twice daily may be safe and effective in the treatment of mild to moderate acne vulgaris.
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A pilot study of the safety and efficacy of Picolinic Acid gel in the treatment of acne vulgaris
The British journal of dermatology, 2007Co-Authors: Michael P Heffernan, Matthew M Nelson, Milan J AnadkatAbstract:Summary Background Cost limitations, adverse effects or lack of efficacy limit the use of current topical therapies in mild to moderate acne vulgaris. Objectives To determine the safety and efficacy of Picolinic Acid, a novel zinc finger therapy, in the treatment of mild to moderate acne vulgaris. Methods Twenty subjects with mild to moderate acne vulgaris were treated at our centre during an open-label study with 10% Picolinic Acid gel (PCL-016) twice daily to the face over 12 weeks. Results Fifteen patients completed the 12-week open-label study. A reduction of 58·2% (P
Vito Lubes - One of the best experts on this subject based on the ideXlab platform.
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Binary and ternary nickel (II) complexes with Picolinic Acid and several amino Acids
Physics and Chemistry of Liquids, 2020Co-Authors: Alba Paz, Mary Lorena Araujo, Vito Lubes, Isis Caceres, Yola Fakhri, Yurgenis Henríquez, Lino HernándezAbstract:In this work, we present the results from a chemical speciation study of binary and ternary complexes formed by Ni(II) ion with Picolinic Acid and the amino Acids = Arginine (HArg), Tryptophan (HTr...
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Determination of stability constants of ternary copper(II) complexes formed with Picolinic Acid and several amino Acids
2018Co-Authors: Lino Hernández, Edgar Del Carpio, Waleska Madden, Giuseppe Lubes, Alejandro Perez, Rafael E. Rodríguez-lugo, Vanessa R. Landaeta, Mary Lorena Araujo, José Daniel Martínez, Vito LubesAbstract:In this work, the formation of ternary complexes with their respective formation constants in the systems formed by copper (II), Picolinic Acid and the amino Acids = histidine (His), aspartic Acid (HGly), proline (HPro), α-alanine (HαAla), β-alanine (HβAla), serine (HSer), threonine (HThr), phenylalanine (HPhe) and methionine (HMet)) was detected. The analysis involves the use of the potentiometric data with the least-squares program LETAGROP in aqueous solution at 25°C in 1M KNO3 solution. The relative stability of the ternary complexes was compared with the binary ones considering the values of Δlog K and log χ. Subsequently using the formation constants, the species distribution diagrams were generated and are briefly discussed here. The Cu (II)–Picolinic Acid–glutamic Acid, Cu (II)–Picolinic Acid–serine and Cu (II)–Picolinic Acid–histidine systems were characterised by UV–Vis molecular absorption spectroscopy and cyclic voltammetry, obtaining results that confirm the formation of ternary complexes with octahedral geometry.
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Ternary Complex Formation between Vanadium(III), DiPicolinic Acid and Picolinic Acid in Aqueous Solution
Journal of Solution Chemistry, 2010Co-Authors: Giuseppe Lubes, Mildred Rodríguez, Vito LubesAbstract:Ternary complex species formed by the V^3+ cation with the Picolinic Acid (Hpic, HL) and diPicolinic Acid (H_2dipic, H_2L) ligands in aqueous solutions have been studied potentiometrically (25 °C, I =3.0 mol⋅dm^−3 KCl ionic medium) and by spectrophotometric measurements. Application of the least-squares computer program LETAGROP to the experimental emf (H) data, taking into account the hydrolytic V(III) species and the binary V^3+–Picolinic Acid and V^3+–diPicolinic Acid complexes, shows that under the investigated conditions the following ternary complexes are formed: [V(dipic)(pic)], [V(dipic)(pic)(OH)]^− and [V(dipic)(pic)_2]^−. The stability constants of the ternary complexes were determined by potentiometric measurements whereas the spectrophotometric measurements were done in order to obtain a qualitative characterization of the complexes formed in aqueous solution.
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Study of the Ternary Complex Formation Between Vanadium(III)-Picolinic Acid and the Amino Acids: Cysteine, Histidine, Aspartic and Glutamic Acids
Journal of Solution Chemistry, 2010Co-Authors: Héctor Rosas, Leydi Erika Sarmiento, Mildred Rodríguez, Vito LubesAbstract:The complex species formed between vanadium(III)-Picolinic Acid (HPic) and the amino Acids: cysteine (H2Cys), histidine (HHis), aspartic Acid (H2Asp) and glutamic Acid (H2Glu) were studied in aqueous solution by means of electromotive forces measurements emf(H) at 25 °C and 3.0 mol⋅dm−3 KCl as ionic medium. Data analysis using the least-squares program LETAGROP indicates the formation of ternary complexes, whose stoichiometric coefficients and stability constant were determined. In the vanadium(III)-Picolinic Acid-cysteine system the model obtained was: [V(Pic)(H2Cys)]2+, [V(Pic)(HCys)]+, V(Pic)(Cys) and [V2O(Pic)(Cys)]+. The vanadium(III)-Picolinic Acid-histidine system contained the following complexes: [V(Pic)(HHis)]2+, [V(Pic)(His)]+, V(Pic)(His)(OH) and [V(Pic)2(HHis)]+. In the vanadium(III)-Picolinic Acid-aspartic Acid system the model obtained was: V(Pic)(Asp), [V(Pic)(Asp)(OH)]− and [V2O(Pic)(Asp)]+ and finally, in the vanadium(III)-Picolinic Acid-glutamic Acid system the complexes: V2O(Pic)2(HGlu)2, V(Pic)(HGlu)2 and V(Pic)2(HGlu) were observed.
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Vanadium(III) Complexes with Picolinic Acid and DiPicolinic Acid in Aqueous Solution
Journal of Solution Chemistry, 2005Co-Authors: Vito LubesAbstract:The complex species formed in aqueous solution (25 ∘C, I = 3.0 mol-dm−3 KCl ionic medium) between V3+ cation and the ligands: Picolinic Acid (Hpic, HL) and diPicolinic Acid (H2dipic, H2L), have been studied potentiometrically and by spectrophotometric measurements. The application of the least-squares computer program LETAGROP to the experimental emf (H) data, taking into account the hydrolytic species of V3+ ion, indicates that under the employed experimental conditions, the formation of the complexes [VL]2+, [V(OH)L]+, [VL2]+, [VL3], [V2OL4] with Picolinic Acid and the complexes [VL]+, [V(OH)L], [V(OH)2L]−, [V(HL)(L)], and [VL2]− with diPicolinic Acid were observed. The stability constants of the complexes formed were determined by potentiometric measurements, and spectrophotometric measurements were done in order to perform a qualitative characterization of the complexes formed in aqueous solution.
Mangesh D. Waghmare - One of the best experts on this subject based on the ideXlab platform.
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Natural Nontoxic Solvents for Recovery of Picolinic Acid by Reactive Extraction
Industrial & Engineering Chemistry Research, 2011Co-Authors: Mangesh D. Waghmare, Kailas L. Wasewar, Shriram S. Sonawane, Diwakar Z. ShendeAbstract:Pyridine carboxylic Acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic Acid, also known as Picolinic Acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic Acid is an advantageous alternative for the production of Picolinic Acid. Reactive extraction is a promising method to recover carboxylic Acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover Acid efficiently. The present paper focuses on the reactive extraction of Picolinic Acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio (
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natural nontoxic solvents for recovery of Picolinic Acid by reactive extraction
Industrial & Engineering Chemistry Research, 2011Co-Authors: Mangesh D. Waghmare, Kailas L. Wasewar, Shriram S. Sonawane, Diwakar Z. ShendeAbstract:Pyridine carboxylic Acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic Acid, also known as Picolinic Acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic Acid is an advantageous alternative for the production of Picolinic Acid. Reactive extraction is a promising method to recover carboxylic Acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover Acid efficiently. The present paper focuses on the reactive extraction of Picolinic Acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio (<0.5), degree of extraction (0.65 to 42.9%...