1
|
Parodi F, Cacciari RD, Mazalu JN, Montejano HA, Reynoso E, Biasutti MA. UVB light influence on the laccase enzyme catalytic activity in reverse micelles and in homogeneous aqueous medium. Amino Acids 2023; 55:469-479. [PMID: 36695918 DOI: 10.1007/s00726-023-03237-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023]
Abstract
Laccase is a versatile enzyme widely used for the oxidation of environmental contaminants and exhibits great potential in many others applications; however, it undergoes photo-degradation when irradiated with UVB light. The photo-stability of this biomolecule can be improved by immobilization in different encapsulation media and reverse micelles have been employed with this purpose. The laccase activity using syringaldazine as substrate has been studied in the absence and in the presence of reverse micelles of 0.15 M of sodium 1,4-bis (2-ethylhexyl) sulfosuccinate (AOT) in isooctane at W0 ([H2O]/[AOT]) = 30, before and after irradiation of the enzyme with UVB light. The kinetic parameters, i.e., Michaelis-Menten constant (KM), catalytic constant (kCAT), and catalytic efficiency (kCAT/KM), were determined by spectroscopic measurements in the micellar system and in homogeneous aqueous medium. The distribution of the substrate in two pseudo-phases (micelle and organic solvent) was taking into account in the kinetic parameters' determinations. The results obtained indicate that the nano-aggregate system confers a solubilization media in the water core of the micelle, both for the enzyme and the substrate, in which the catalytic function of the enzyme is preserved. On the other hand, in homogeneous aqueous medium kCAT/KM value, it is reduced by ~50% after UVB irradiation of the enzyme, while in micellar medium, less than 10% of the activity was affected. This mean that the enzyme achieves a considerably photo-protection when it is irradiated with UVB light in reverse micelles as compared with the homogeneous aqueous medium. This phenomenon can be mainly due to the confinement of the biomolecule inside the micelle. Physical properties of the nano-environment could affect photochemical reactions.
Collapse
Affiliation(s)
- Facundo Parodi
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina
- Instituto Para El Desarrollo Agroindustrial y de la Salud (IDAS), CONICET-UNRC, Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina
| | - R Daniel Cacciari
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET-UNLP, Diagonal 113 y 64, Casco Urbano, B1900, La Plata, Buenos Aires, Argentina
| | - Jeremías N Mazalu
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina
| | - Hernán A Montejano
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), CONICET-UNRC, Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina
| | - Eugenia Reynoso
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina.
- Instituto Para El Desarrollo Agroindustrial y de la Salud (IDAS), CONICET-UNRC, Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina.
| | - M Alicia Biasutti
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina.
- Instituto Para El Desarrollo Agroindustrial y de la Salud (IDAS), CONICET-UNRC, Ruta Nacional 36 Km 601, X5804BYA, Río Cuarto, Córdoba, Argentina.
| |
Collapse
|
2
|
Monti GA, Falcone RD, Moyano F, Correa NM. Green AOT reverse micelles as nanoreactors for alkaline phosphatase. The hydrogen bond "dances" between water and the enzyme, the reaction product, and the reverse micelles interface. RSC Adv 2023; 13:1194-1202. [PMID: 36686944 PMCID: PMC9811498 DOI: 10.1039/d2ra06296h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
In this work, we present an investigation of the influence of water encapsulated in 1,4-bis-2-ethylhexylsulfosuccinate/methyl laurate and 1,4-bis-2-ethylhexylsulfosuccinate/isopropyl myristate reverse micelles on the enzymatic hydrolysis of 1-naphthyl phosphate by alkaline phosphatase. Our results show that the enzyme is active in the biocompatible reverse micelles studied and that the Michaelis-Menten kinetic model is valid in all systems. We found that both micellar systems studied have a particular behavior toward pH and that the penetration of external solvents into the interfaces is crucial to understanding the effect. Methyl laurate does not disrupt the interface and is not necessary to control the pH value since alkaline phosphatase in the center of the micelles is always solvated similarly. In contrast, isopropyl myristate disrupts the interfaces so that the water and 1-naphthol molecules cannot form hydrogen bond interactions with the polar head of the surfactant. Then, when the water is at pH = 7, the 1-naphthol moves away to the interfaces inhibiting alkaline phosphatase which is not observable when the water is at pH = 10. Our study shows that the concept of pH cannot be used directly in a confined environment. In addition, our research is of great importance in the field of reactions that occur in reverse micelles, catalyzed by enzymes.
Collapse
Affiliation(s)
- Gustavo A. Monti
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, CONICET-UNRC), Departamento de Química, Universidad Nacional de Río CuartoRío CuartoArgentina,Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA, CONICET-UNRC), Departamento de Tecnología Química, Universidad Nacional de Río CuartoRío CuartoArgentina
| | - R. Darío Falcone
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, CONICET-UNRC), Departamento de Química, Universidad Nacional de Río CuartoRío CuartoArgentina
| | - Fernando Moyano
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, CONICET-UNRC), Departamento de Química, Universidad Nacional de Río CuartoRío CuartoArgentina
| | - N. Mariano Correa
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, CONICET-UNRC), Departamento de Química, Universidad Nacional de Río CuartoRío CuartoArgentina
| |
Collapse
|
3
|
Małycha K, Burakowski A, Gliński J, Niu H, Bai SL, Orzechowski K. Characterization of isooctane/AOT/water reverse micelles by dielectric spectroscopy, dynamic light scattering and acoustic methods. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
4
|
Cobo Solis AK, Mariano Correa N, Molina PG. Electrochemical and photophysical behavior of 1-naphthol in benzyl-n-hexadecyldimethylammonium 1,4-bis(2-ethylhexyl)sulfosuccinate large unilamellar vesicles. Phys Chem Chem Phys 2016; 18:15645-53. [DOI: 10.1039/c6cp01979j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The behavior of 1-naphthol and its partition process in LUVs formed from a new catanionic surfactant were studied by electrochemical and spectroscopic techniques.
Collapse
Affiliation(s)
- Airam K. Cobo Solis
- Departamento de Química
- Facultad de Ciencias Exactas
- Físico-Químicas y Naturales
- Universidad Nacional de Río Cuarto
- Río Cuarto
| | - N. Mariano Correa
- Departamento de Química
- Facultad de Ciencias Exactas
- Físico-Químicas y Naturales
- Universidad Nacional de Río Cuarto
- Río Cuarto
| | - Patricia G. Molina
- Departamento de Química
- Facultad de Ciencias Exactas
- Físico-Químicas y Naturales
- Universidad Nacional de Río Cuarto
- Río Cuarto
| |
Collapse
|
5
|
Kotake-Nara E, Yonekura L, Nagao A. Glyceroglycolipids Affect Uptake of Carotenoids Solubilized in Mixed Micelles by Human Intestinal Caco-2 Cells. Lipids 2015; 50:847-60. [PMID: 26012480 DOI: 10.1007/s11745-015-4033-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 05/01/2015] [Indexed: 10/23/2022]
Abstract
We previously reported that phospholipids markedly affected the uptake of carotenoids solubilized in mixed micelles by human intestinal Caco-2 cells. In the present study, we found that two classes of dietary glyceroglycolipids and the corresponding lysoglyceroglycolipids affected uptake of β-carotene and lutein by differentiated Caco-2 cells. The levels of carotenoid uptake from micelles containing digalactosyldiacylglycerol or sulfoquinovosyldiacylglycerol were significantly lower than that from control micelles. On the other hand, the uptakes from micelles containing digalactosylmonoacylglycerol or sulfoquinovosylmonoacylglycerol were significantly higher than that from control micelles. In dispersed cells and Caco-2 cells with poor cell-to-cell adhesion, however, the levels of uptake from micelles containing these lyso-lipids were much lower than that from control micelles. The uptake levels from control micelles were markedly decreased depending on the development of cell-to-cell/cell-matrix adhesion in Caco-2 cells, but the uptake levels from the micelles containing these lyso-lipids were not substantially changed, suggesting that the intercellular barrier formed by cell-to-cell/cell-matrix adhesion inhibited the uptake from control micelles, but not from the lyso-lipid-containing micelles. The lyso-lipids appeared to enhance carotenoid uptake by decreasing the intercellular barrier integrity. The results showed that some types of glyceroglycolipids have the potential to modify the intestinal uptake of carotenoids.
Collapse
Affiliation(s)
- Eiichi Kotake-Nara
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki, 305-8642, Japan,
| | | | | |
Collapse
|
6
|
Ferreyra DD, Correa NM, Silber JJ, Falcone RD. The effect of different interfaces and confinement on the structure of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide entrapped in cationic and anionic reverse micelles. Phys Chem Chem Phys 2012; 14:3460-70. [DOI: 10.1039/c2cp23481e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
7
|
Quintana SS, Falcone RD, Silber JJ, Correa NM. Comparison between Two Anionic Reverse Micelle Interfaces: The Role of Water-Surfactant Interactions in Interfacial Properties. Chemphyschem 2011; 13:115-23. [DOI: 10.1002/cphc.201100638] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 10/21/2011] [Indexed: 11/12/2022]
|
8
|
Silva OF, Fernández MA, Silber JJ, de Rossi RH, Correa NM. Inhibited Phenol Ionization in Reverse Micelles: Confinement Effect at the Nanometer Scale. Chemphyschem 2011; 13:124-30. [DOI: 10.1002/cphc.201100634] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/05/2011] [Indexed: 11/11/2022]
|
9
|
Boscencu R, Ilie M, Socoteanu R. Spectroscopic behavior of some A(3)B type tetrapyrrolic complexes in several organic solvents and micellar media. Int J Mol Sci 2011; 12:5552-64. [PMID: 22016608 PMCID: PMC3189732 DOI: 10.3390/ijms12095552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/19/2011] [Accepted: 08/26/2011] [Indexed: 11/16/2022] Open
Abstract
The paper presents spectral studies of some unsymmetrical A3B tetrapyrrolic, porphyrin-type complexes with Cu(II) and Zn(II) in different solvents and micellar media aimed at estimating their properties in connection with the living cell. The results indicate that the position of the absorption and emission peaks is mostly influenced by the central metal ion and less by the environmental polarity or the peripheric substituents of the porphyrinic core. The comparison between the overall absorption and emission spectra of the compounds in methanol or cyclohexane vs. direct and reverse Triton X micellar systems, respectively, suggests for all compounds the localization at the interface between the polyethylene oxide chains and the tert-octyl-phenyl etheric residue of the Triton X-100 molecules. These findings could be important when testing the compounds embedded in liposomes or other delivery systems to the targeted cell.
Collapse
Affiliation(s)
- Rica Boscencu
- Faculty of Pharmacy, “Carol Davila” University of Medicine and Pharmacy, 6 Traian Vuia Street, Bucharest 020956, Romania; E-Mail:
| | - Mihaela Ilie
- Faculty of Pharmacy, “Carol Davila” University of Medicine and Pharmacy, 6 Traian Vuia Street, Bucharest 020956, Romania; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +4-021-3111152; Fax: +4-021-3111152
| | - Radu Socoteanu
- “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, 202 Splaiul Independenţei, Bucharest 060021, Romania; E-Mail:
| |
Collapse
|
10
|
Moyano F, Falcone R, Mejuto J, Silber J, Correa N. Cationic Reverse Micelles Create Water with Super Hydrogen-Bond-Donor Capacity for Enzymatic Catalysis: Hydrolysis of 2-Naphthyl Acetate by α-Chymotrypsin. Chemistry 2010; 16:8887-93. [DOI: 10.1002/chem.201000437] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
11
|
Salcedo CL, López de Mishima BA, Nazareno MA. Walnuts and almonds as model systems of foods constituted by oxidisable, pro-oxidant and antioxidant factors. Food Res Int 2010. [DOI: 10.1016/j.foodres.2010.02.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
12
|
Khoo HE, Ismail A, Mohd-Esa N, Idris S. Carotenoid content of underutilized tropical fruits. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2008; 63:170-175. [PMID: 18810641 DOI: 10.1007/s11130-008-0090-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This study was conducted to evaluate the total carotene content (TCC) and beta carotene (BC) in the selected underutilized tropical fruits. TCC of underutilized fruits estimated by spectrophotometric method was in the range of 1.4-19.8 mg/100 g edible portion. The TCC of these fruits decreased in the order: Jentik-jentik > Durian Nyekak 2 > Durian Nyekak 1 > Cerapu 2 > Cerapu 1 > Tampoi Kuning > Bacang 1 > Kuini > Jambu Mawar > Bacang 2 > Durian Daun > Bacang 3 > Tampoi Putih > Jambu Susu. BC contents estimated by HPLC method were highest in Jentik-jentik, followed by Cerapu 2, Durian Nyekak 2, Tampoi Kuning, Durian Nyekak 1, and Cerapu 1, which had a range of 68-92% of BC in TCC. These underutilized fruits have an acceptable amount of carotenoids that are potential antioxidant fruits.
Collapse
Affiliation(s)
- Hock Eng Khoo
- Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | | | | | | |
Collapse
|
13
|
Silva OF, Silber JJ, de Rossi RH, Correa NM, Fernandez MA. On the Possibility That Cyclodextrins' Chiral Cavities Can Be Available on AOT n-Heptane Reverse Micelles. A UV−Visible and Induced Circular Dichroism Study. J Phys Chem B 2007; 111:10703-12. [PMID: 17705421 DOI: 10.1021/jp0724424] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The formation of reverse micelles (RMs) of sodium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT) in n-heptane including two different beta-cyclodextrin (beta-CD) derivatives (hydroxypropyl-beta-CD, hp-beta-CD, and decenyl succinyl-beta-CD, Mod-beta-CD) is reported. Both cyclodextrins can be incorporated into AOT RMs in different zones within the aggregate, while beta-CD cannot. Using UV-vis and induced circular dichroism (ICD) spectroscopy and different achiral molecular probes (some azo dyes, p-nitroaniline and ferrocene), it was possible to determine that Mod-beta-CD is located with its cavity at the oil side of the AOT RM interface, while for hp-beta-CD the cavity is inside the RM water pool. Among the molecular probes used, methyl orange (MO) was the only one which gave the ICD signal when dissolved in the AOT RMs with hp-beta-CD, so a detailed study of MO behavior in homogeneous media was also performed to compare with the microheterogeneous media. The solvatochromic behavior of the dye depends not only on the polarity of the media but also on other specific solvent properties. A Kamlet-Taft analysis shows that the MO absorption spectrum shifts to longer wavelength with an increase in the solvent polarity-polarizability (pi*) and the hydrogen donor ability (alpha) of the medium. MO appears to be almost 3 times more sensitive to the pi* parameter than to the alpha parameter. In addition, from the MO absorption spectral changes with the hp-beta-CD concentration, the association equilibrium constants in pure water (K11W) and inside the RMs (K11RM) were computed. The results show that K11W is almost 10 times larger than the value inside the RMs. The latter can be explained considering that MO resides anchored to the RM interface through hydrogen bond interaction with the hydration bound water. This study shows for the first time that the cyclodextrin chiral cavity is available for a guest in an organic medium such as the RMs; therefore, we have created a potentially powerful nanoreactor with two different confined regions in the same aggregate: the polar core of the RMs and the chiral hydrophobic cavity of cyclodextrin.
Collapse
Affiliation(s)
- O Fernando Silva
- Instituto de Investigaciones en Físico-Química de Córdoba (INFIQC), Facultad de Ciencias Químicas, Departamento de Química OrgAnica, Universidad Nacional de Córdoba, Ciudad Universitaria, (X5000HUA) Córdoba, Argentina
| | | | | | | | | |
Collapse
|
14
|
Montenegro MA, Nazareno MA, Durantini EN, Borsarelli CD. Singlet Molecular Oxygen Quenching Ability of Carotenoids in a Reverse-micelle Membrane Mimetic System¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750353smoqao2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
15
|
García-Río L, Godoy A, Rodríguez-Dafonte P. Influence of the Oil on the Properties of Microemulsions as Reaction Media. European J Org Chem 2006. [DOI: 10.1002/ejoc.200600086] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
16
|
Correa NM, Levinger NE. What Can You Learn from a Molecular Probe? New Insights on the Behavior of C343 in Homogeneous Solutions and AOT Reverse Micelles. J Phys Chem B 2006; 110:13050-61. [PMID: 16805613 DOI: 10.1021/jp0572636] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The behavior of C343, a common molecular probe utilized in solvation dynamics experiments, was studied in homogeneous media and in aqueous and nonaqueous reverse micelles (RMs). In homogeneous media, the Kamlet and Taft solvatochromic comparison method quantified solute-solvent interactions from the absorption and emission bands showing that the solvatochromic behavior of the dye depends not only on the polarity of the medium but also on the hydrogen-bonding properties of the solvent. Specifically, in the ground state the molecule displays a bathochromic shift with the polarity polarizability (pi) and the H-bond acceptor (beta) ability of the solvents and a hypsochromic shift with the hydrogen donor ability (alpha) of the media. The carboxylic acid group causes C343 to display greater sensitivity to the beta than to the pi polarity parameter; this sensitivity increases in the excited state, while the dependence on alpha vanishes. This demonstrates that C343 forms a stable H-bond complex with solvents with high H-bond acceptor ability (high beta) and low H-bond donor character (low alpha). Spectroscopy in nonpolar solvents reveals J-aggregate formation. With information from the Kamlet-Taft analysis, C343 was used to explore RMs composed of water or polar solvents/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/isooctane using absorption, emission, and time-resolved spectroscopies. Sequestered polar solvents included ethylene glycol (EG), formamide (FA), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA). Dissolved in the AOT RM systems at low concentration, C343 exists as a monomer, and when introduced to the RM samples in its protonated form, C343 remains protonated driving it to reside in the interface rather than the water pool. The solvathochromic behavior of the dye depends the specific polar solvent encapsulated in the RMs, revealing different types of interactions between the solvents and the surfactant. EG and water H-bond with the AOT sulfonate group destroying their bulk H-bonded structures. While water remains well segregated from the nonpolar regions, EG appears to penetrate into the oil side of the interface. In aqueous AOT RMs, C343 interacts with neither the sulfonate group nor the water, perhaps because of intramolecular H-bonding in the dye. DMF and DMA interact primarily through dipole-dipole forces, and the strong interactions with AOT sodium counterions destroy their bulk structure. FA also interacts with the Na+ counterions but retains its H-bond network present in bulk solvent. Surprisingly, FA appears to be the only polar solvent other than water forming a "polar-solvent pool" with macroscopic properties similar to the bulk.
Collapse
Affiliation(s)
- N Mariano Correa
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
| | | |
Collapse
|
17
|
Zingaretti L, Mariano Correa N, Boscatto L, Chiacchiera SM, Durantini EN, Bertolotti SG, Rivarola CR, Silber JJ. Distribution of amines in water/AOT/n-hexane reverse micelles: influence of the amine chemical structure. J Colloid Interface Sci 2005; 286:245-52. [PMID: 15848423 DOI: 10.1016/j.jcis.2004.12.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 12/20/2004] [Indexed: 10/25/2022]
Abstract
The distribution of different aliphatic and aromatic amines: n-butylamine (n-BA), isobutylamine (i-BA), tert-butylamine (t-BA), piperidine (PIP), N,N-dimethylaniline (DMA) and N-methylaniline (MA) in water/sodium 1,4-bis(2-ethylhexyl)sulfosuccinate(AOT)/n-hexane reverse micelles was investigated by steady-state fluorescence measurements. The partition constants were measured by an indirect method based on the effect that amine partitioning exert on the bimolecular rate of the reaction between a microphase incorporated fluorophore (Ru(bpy)2+(3)) and the quencher, (Fe(CN)3-(6)). For MA, that can act as a quencher of the fluorophore a direct method was used. The results show that primary amines have larger partition constants than the secondary ones. For tertiary amines the distribution constants were practically negligible. Laser flash photolysis experiments confirmed that tertiary amines, both aliphatic and aromatic, are not incorporated to the micellar pseudophase. The effect of the amine structure on the partition constant was analyzed through linear solvation free energy relationships (LSER) using solute parameters and compared with those obtained for alcohols. Hydrogen bond interactions with the AOT polar heads appear to be the main driving force for the distribution of amines between the organic and micellar pseudophases, whereas the size of the alkyl or aromatic group tends to hinder it.
Collapse
Affiliation(s)
- Lilian Zingaretti
- Departamento de Química, Universidad Nacional de Río Cuarto, Agencia Postal No. 3, 5800 Río Cuarto, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Correa NM, Zorzan DH, Chiarini M, Cerichelli G. Reverse Micellar Aggregates: Effect on Ketone Reduction. 1. Substrate Role. J Org Chem 2004; 69:8224-30. [PMID: 15549791 DOI: 10.1021/jo049173n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The reduction of three aromatic ketones, acetophenone (AF), 4-methoxyacetophenone (MAF), and 3-chloroacetophenone (CAF), by NaBH(4) was followed by UV-vis spectroscopy in reverse micellar systems of water/AOT/isooctane at 25.0 degrees C (AOT is sodium 1,4-bis-2-ethylhexylsulfosuccinate). The first-order rate constants, k(obs), increase with the concentration of surfactant due to the substrate incorporation at the reverse micelle interface, where the reaction occurs. For all the ketones the reactivity is lower at the micellar interface than in water, probably reflecting the low affinity of the anionic interface for BH(4)(-). Kinetic profiles upon water addition show maxima in k(obs) at W(0) approximately 5 probably reflecting a strong interaction between water and the ionic headgroup of AOT; at W(0) < 5 by increasing W(0) BH(4)(-) is repelled from the anionic interface once the water pool forms. The order of reactivity was CAF >> AF > MAF. Application of a kinetic model based on the pseudophase formalism, which considers distribution of the ketones between the continuous medium and the interface, and assumes that reaction take place only at the interface, gives values of the rate constants at the interface of the reverse micellar system. At W(0) = 5, we conclude that NaBH(4) is wholly at the interface, and at W(0) = 10 and 15, where there are free water molecules, the partitioning between the interface and the water pool has to be considered. The results were used to estimate the ketone and borohydride distribution constants between the different pseudophases as well as the second-order reaction rate constant at the micellar interface.
Collapse
Affiliation(s)
- N Mariano Correa
- Dipartimento di Chimica, Ingegneria Chimica e Materiali. Facoltà di Scienze MM FF NN Università degli Studi dell'Aquila, 67100 L'Aquila, Italy
| | | | | | | |
Collapse
|
19
|
Correa NM, Zorzan DH, D'Anteo L, Lasta E, Chiarini M, Cerichelli G. Reverse Micellar Aggregates: Effect on Ketone Reduction. 2. Surfactant Role. J Org Chem 2004; 69:8231-8. [PMID: 15549792 DOI: 10.1021/jo049172v] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kinetics of the reduction of 3-chloroacetophenone (CAF) with sodium borohydride (NaBH(4)) were followed by UV-vis spectroscopy at 27.0 degrees C in different reverse micellar media, toluene/BHDC/water and toluene/AOT/water, and compared with results in an isooctane/AOT/water reverse micellar system. AOT is sodium 1,4-bis-2-ethylhexylsulfosuccinate, and BHDC is benzyl-n-hexadecyl dimethylammonium chloride. The kinetic profiles were investigated as a function of variables such as surfactant and NaBH(4) concentration and the amount of water dispersed in the reverse micelles, W(0) = [H(2)O]/[surfactant]. In all cases, the first-order rate constant, k(obs), increases with the concentration of surfactant as a consequence of incorporating the substrate into the interface of the reverse micelles where the reaction takes place. The reaction is faster at the cationic interface than at the anionic one probably because the negative ion BH(4)(-) is part of the cationic interface. The effect of the external solvent on the reaction shows that reduction is favored in the isooctane/AOT/water reverse micellar system than that with an aromatic solvent. This is probably due to BH(4)(-) being more in the water pool of the toluene/AOT/water reverse micellar system. The kinetic profile upon water addition depends largely on the type of interface. In the BHDC system, k(obs) increases with W(0) in the whole range studied while in AOT the kinetic profile has a maximum at W(0) approximately 5, probably reflecting the fact that BH(4)(-) is part of the cationic interface while, in the anionic one, there is a strong interaction between water and the polar headgroup of AOT below W(0) = 5 and, above that, BH(4)(-) is repelled from the interface once the water pool has formed. Application of a kinetic model based on the pseudophase formalism, which considers the distribution of the ketone between the continuous medium and the interface and assumes that reaction takes place only at the interface, has enabled us to estimate rate constants at the interface of the reverse micellar systems. At W(0) < 10, it was considered that NaBH(4) is wholly at the interface and, at W(0) >/= 10, where there are free water molecules, also the partitioning between the interface and the water pool was taken into account. The results were used to evaluate CAF and NaBH(4) distribution constants between the different pseudophases as well as the second-order reaction rate constant of the reduction reaction in the micellar interface.
Collapse
Affiliation(s)
- N Mariano Correa
- Dipartimento di Chimica Ingegneria Chimica e Materiali. Facoltà di Scienze MM FF NN, Università degli Studi dell'Aquila, L'Aquila 67100, Italy
| | | | | | | | | | | |
Collapse
|
20
|
|
21
|
Szymula M, Radzki S. A study of molecular complex formation between propyl gallate and ascorbic acid in the microemulsion phase of sodium dodecyl sulfate, pentanol and water system. Colloids Surf B Biointerfaces 2004; 35:249-57. [PMID: 15261038 DOI: 10.1016/s0927-7765(03)00103-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2003] [Indexed: 11/22/2022]
Abstract
The association between two water-soluble antioxidants, i.e. ascorbic acid and propyl gallate have been studied by absorption spectroscopy in microemulsion formed in sodium dodecyl sulfate/pentanol/water micellar system. It has been shown that propyl gallate forms 1:1 molecular complex with ascorbic acid in every solution. Evolution of the absorption spectra during the study of molecular complex formation goes through well-defined isosbestic points. The association constants were calculated using curve-fitting procedure. The observed interactions are stronger in the less polar solvents.
Collapse
Affiliation(s)
- M Szymula
- Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie-Skłodowska University, M. Curie-Skłodowska Sq. 3, 20-031 Lublin, Poland.
| | | |
Collapse
|
22
|
Scalise I, Durantini EN. Photodynamic effect of metallo 5-(4-carboxyphenyl)-10,15,20-tris(4-methylphenyl) porphyrins in biomimetic AOT reverse micelles containing urease. J Photochem Photobiol A Chem 2004. [DOI: 10.1016/s1010-6030(03)00317-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
23
|
Montenegro MA, Nazareno MA, Durantini EN, Borsarelli CD. Singlet molecular oxygen quenching ability of carotenoids in a reverse-micelle membrane mimetic system. Photochem Photobiol 2002; 75:353-61. [PMID: 12003124 DOI: 10.1562/0031-8655(2002)075<0353:smoqao>2.0.co;2] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The influence of the medium heterogeneity upon the bimolecular rate constants for the physical quenching, kq, and chemical quenching, kr, of singlet molecular oxygen O2(1deltag) by seven natural and three synthetic carotenoids (CAR) with different substituent patterns was studied in a reverse micelle system of sodium bis(2-ethylhexyl)sulfosuccinate, hexane and water. Because O2(1deltag) was generated inside the water pools of the reverse micelles by photosensitization of the water-soluble dye rose bengal and the CAR are mainly located in the external hexane pseudophase, the quenching process was interpreted using a pseudophase model for the partition of 02(1deltag) between the water pools and the organic pseudophases. The kq values were mainly dependent on the extent of the double-bond conjugation of the CAR, as demonstrated by a good empirical relationship between log(k(q)) and the energy E(S) of the longest wavelength transition pi-->pi* of the CAR. In contrast, the kr values were almost independent of the extent of the double-bond-conjugated system and about four orders of magnitude lower than kq. However, in all cases, CAR photobleaching was observed with the formation of various oxidation products, depending on the photosensitization time. Chromatographic and spectroscopic product analysis for the reaction products of beta-carotene with O2(1deltag) indicated the formation of the beta-carotene-5,8-endoperoxide as the primary oxidation product.
Collapse
Affiliation(s)
- Mariana A Montenegro
- Instituto de Ciencias Químicas, Facultad de Agronomía y Agroindustrias, Universidad Nacional de Santiago del Estero, Santiago del Estero, Argentina
| | | | | | | |
Collapse
|