Theoretical studies and vibrational spectra of 1H -indole-3-acetic acid: Exploratory conformational analysis of dimeric species

Theoretical studies on 1H-indole-3-acetic acid (IAA) were performed to investigate the conformational properties of dimeric species and vibrational spectra. Experimental infrared spectra at 100 K and 297 K and Raman spectrum at 297 K were analyzed and compared against calculations performed at B3LYP/6-31G** level. A exploratory study of the conformational space of dimeric species was performed. Our analysis showed that dimeric forms predicted theoretically contribute distinctively to the assignments of experimental results. These structures are defined by the orientation of the acetyl moieties with respect to the plane of indole ring. The dimers are formed by two symmetrical IAA monomers (one of them with the acetyl moiety upward oriented, Re-face, and the other isomer having the acetyl moiety downward oriented, Si-face) in tail-to-tail way. The X-ray geometry and FTIR vibrational frequencies were compared with the results of DFT calculations. A conformational equilibrium involving the non-equivalent IAA dimers: CCT-CCT, A+A+T-A-A-T, A+A-T-A-A+T, and A+CT-A-CT was found. The relation of the conformational properties of the IAA molecule with the features of the vibrational spectra was described in detail. The band assignments were discussed as related to the conformations properties. Our analysis shows the significance of the theoretical study of the conformational space of the monomeric molecule in the rationalization of experimental results.Centro de Química InorgánicaFacultad de Ingenierí

Conformational and stereoelectronic investigation of tryptamine : An AIM/NBO study

Due to the free radical scavenger properties of Tryptamine (TRA), as well as of others indole derivatives, it is in our interest to explore deeply the stereoelectronic aspects that would be relevant in their stabilization and antioxidant activity. In this work the conformational space of TRA was scanned using molecular dynamics complemented with functional density calculations at B3LYP/6-31 + G** level. Twenty one conformers of lowest energy were obtained, their electronic distributions were analyzed at a higher calculation level, thus improving the basis set (B3LYP/6-311++G**). A topological study based on Bader’s theory (AIM: atoms in molecules) and natural bond orbital (NBO) framework was performed. The study was enriched by a deep analysis of maps of molecular electrostatic potential (MEP) through a coordinated NBO/AIM analysis. The conformational preferences were explained by hyperconjugative interactions, which were revealed by NBO data. Because radical scavenging by indolic compounds is strongly modulated by their functional residues our study was related to similar analysis done previously on Indole and 1H-indole-3-acetic acid (IAA). Therefore, the conformational space of TRA was studied from a new perspective focusing on a deep analysis of the geometric and electronic properties of TRA conformers. The changes of the electronic distribution introduced by the substituent and the conformational flexibility of the side chain were addressed. The results reported contribute to the understanding of the structure, stability and reactivity of TRA and others indole derivatives.Centro de Química Inorgánic

Conformational and stereoelectronic investigation of tryptamine : An AIM/NBO study

Due to the free radical scavenger properties of Tryptamine (TRA), as well as of others indole derivatives, it is in our interest to explore deeply the stereoelectronic aspects that would be relevant in their stabilization and antioxidant activity. In this work the conformational space of TRA was scanned using molecular dynamics complemented with functional density calculations at B3LYP/6-31 + G** level. Twenty one conformers of lowest energy were obtained, their electronic distributions were analyzed at a higher calculation level, thus improving the basis set (B3LYP/6-311++G**). A topological study based on Bader’s theory (AIM: atoms in molecules) and natural bond orbital (NBO) framework was performed. The study was enriched by a deep analysis of maps of molecular electrostatic potential (MEP) through a coordinated NBO/AIM analysis. The conformational preferences were explained by hyperconjugative interactions, which were revealed by NBO data. Because radical scavenging by indolic compounds is strongly modulated by their functional residues our study was related to similar analysis done previously on Indole and 1H-indole-3-acetic acid (IAA). Therefore, the conformational space of TRA was studied from a new perspective focusing on a deep analysis of the geometric and electronic properties of TRA conformers. The changes of the electronic distribution introduced by the substituent and the conformational flexibility of the side chain were addressed. The results reported contribute to the understanding of the structure, stability and reactivity of TRA and others indole derivatives.Centro de Química Inorgánic

Cancer health disparities in racial/ethnic minorities in the United States

There are well-established disparities in cancer incidence and outcomes by race/ethnicity that result from the interplay between structural, socioeconomic, socio-environmental, behavioural and biological factors. However, large research studies designed to investigate factors contributing to cancer aetiology and progression have mainly focused on populations of European origin. The limitations in clinicopathological and genetic data, as well as the reduced availability of biospecimens from diverse populations, contribute to the knowledge gap and have the potential to widen cancer health disparities. In this review, we summarise reported disparities and associated factors in the United States of America (USA) for the most common cancers (breast, prostate, lung and colon), and for a subset of other cancers that highlight the complexity of disparities (gastric, liver, pancreas and leukaemia). We focus on populations commonly identified and referred to as racial/ethnic minorities in the USA—African Americans/Blacks, American Indians and Alaska Natives, Asians, Native Hawaiians/other Pacific Islanders and Hispanics/Latinos. We conclude that even though substantial progress has been made in understanding the factors underlying cancer health disparities, marked inequities persist. Additional efforts are needed to include participants from diverse populations in the research of cancer aetiology, biology and treatment. Furthermore, to eliminate cancer health disparities, it will be necessary to facilitate access to, and utilisation of, health services to all individuals, and to address structural inequities, including racism, that disproportionally affect racial/ethnic minorities in the USA.Fil: Zavala, Valentina A.. University of California; Estados UnidosFil: Bracci, Paige M.. University of California; Estados UnidosFil: Carethers, John M.. University of Michigan; Estados UnidosFil: Carvajal Carmona, Luis. University of California at Davis; Estados UnidosFil: Coggins, Nicole B.. University of California at Davis; Estados UnidosFil: Cruz Correa, Marcia R.. Universidad de Puerto Rico; Puerto RicoFil: Davis, Melissa. No especifíca;Fil: de Smith, Adam J.. University of California; Estados UnidosFil: Dutil, Julie. Ponce Research Institute; Puerto RicoFil: Figueiredo, Jane C.. Cedars Sinai Medical Center; Estados UnidosFil: Fox, Rena. University of California; Estados UnidosFil: Graves, Kristi D.. University Of Georgetown; Estados UnidosFil: Gomez, Scarlett Lin. University of California; Estados UnidosFil: Llera, Andrea Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Neuhausen, Susan L.. No especifíca;Fil: Newman, Lisa. No especifíca;Fil: Nguyen, Tung. University of California; Estados UnidosFil: Palmer, Julie R.. National Institutes of Health; Estados UnidosFil: Palmer, Nynikka R.. University of California; Estados UnidosFil: Pérez Stable, Eliseo J.. National Institutes of Health; Estados UnidosFil: Piawah, Sorbarikor. University of California; Estados UnidosFil: Rodriquez, Erik J.. National Institutes of Health; Estados UnidosFil: Sanabria Salas, María Carolina. Instituto Nacional de Cancerología; ColombiaFil: Schmit, Stephanie L.. University of Southern California; Estados UnidosFil: Serrano Gomez, Silvia J.. Instituto Nacional de Cancerología; ColombiaFil: Stern, Mariana Carla. University of Southern California; Estados UnidosFil: Weitzel, Jeffrey. No especifíca;Fil: Yang, Jun J.. St. Jude Children’s Research Hospital; Estados UnidosFil: Zabaleta, Jovanny. No especifíca;Fil: Ziv, Elad. University of California; Estados UnidosFil: Fejerman, Laura. University of California; Estados Unido

Detección de aminoácidos por cromatografía en capa delgada monodimensional

Se desarrolla un método que permite detectar con rapidez, y en forma sencilla en el laboratorio de análisis clínico, la presencia de aminoácidos en concentraciones patológicas en orina. Se incorpora una etapa de extracción en fase sólida (EFS) que limpia la muestra de potenciales interferentes y se somete al concentrado a una etapa ulterior de Cromatografía en Capa Delgada (CCD) monodimensional. Se utiliza silicagel como adsorbente y ninhidrina como revelador. Se determinan los Rf de las distintas fracciones de aminoácidos y se compara el perfil obtenido con el de muestras de referencia. La eficiencia de la extracción, la aceptable resolución y la repetibilidad alcanzada en la CCD contribuyen a la utilidad del método propuesto en el diagnóstico clínico de rutina

Aqueous solvent effects on the conformational space of tryptamine: Structural and electronic analysis

The TRA (3-[2-aminoethyl]indole) is an important neurotransmitter with a close structural and chemical similarity to the neurotransmitter serotonin (5-hydroxytryptamine), and to melatonin (5-methoxy-N-acetyltryptamine), which plays a key role in daily human behavior. Moreover, TRA, and other indolic compounds are very efficient antioxidants. In this work the conformational space of TRA was scanned in aqueous solution, simulating the solvent by the polarizable continuum model. Geometry optimizations were performed at B3LYP/6-31+G** level. Electronic distributions were analyzed at a better calculation level, thus improving the basis set (6-311++G**). A topological study based on Bader’s theory (atoms in molecules) and natural bond orbital (NBO) framework was performed. Structural changes found in solution were related with charge delocalization mechanisms, which explained the changes in the conformational relative population in aqueous phase. Solvent effects on molecular electrostatic potential (MEPs) were also quantified and rationalized through charge delocalization mechanisms, thus connecting changes in MEPs with changes in structure, bond polarization, orbital bonding populations, natural charges, and bond topological properties. Moreover, polarizabilities and dipolar moments were calculated. All conformers were taken into account. Our results are the first prediction of TRA polarizabilities. The results reported contribute to the understanding of the structure, stability and reactivity of TRA and other indole derivatives.Fil: Lobayan, Rosana M.. Universidad de la Cuenca del Plata; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; ArgentinaFil: Pérez Schmit, María C.. Universidad de la Cuenca del Plata; ArgentinaFil: Jubert, Alicia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Vitale, Arturo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

Theoretical studies and vibrational spectra of 1H -indole-3-acetic acid: Exploratory conformational analysis of dimeric species

Theoretical studies on 1H-indole-3-acetic acid (IAA) were performed to investigate the conformational properties of dimeric species and vibrational spectra. Experimental infrared spectra at 100 K and 297 K and Raman spectrum at 297 K were analyzed and compared against calculations performed at B3LYP/6-31G** level. A exploratory study of the conformational space of dimeric species was performed. Our analysis showed that dimeric forms predicted theoretically contribute distinctively to the assignments of experimental results. These structures are defined by the orientation of the acetyl moieties with respect to the plane of indole ring. The dimers are formed by two symmetrical IAA monomers (one of them with the acetyl moiety upward oriented, Re-face, and the other isomer having the acetyl moiety downward oriented, Si-face) in tail-to-tail way. The X-ray geometry and FTIR vibrational frequencies were compared with the results of DFT calculations. A conformational equilibrium involving the non-equivalent IAA dimers: CCT-CCT, A+A+T-A-A-T, A+A-T-A-A+T, and A+CT-A-CT was found. The relation of the conformational properties of the IAA molecule with the features of the vibrational spectra was described in detail. The band assignments were discussed as related to the conformations properties. Our analysis shows the significance of the theoretical study of the conformational space of the monomeric molecule in the rationalization of experimental results.Centro de Química InorgánicaFacultad de Ingenierí

Aqueous solvent effects on the conformational space of tryptamine: structural and electronic analysis

The TRA (3-[2-aminoethyl]indole) is an important neurotransmitter with a close structural and chemical similarity to the neurotransmitter serotonin (5-hydroxytryptamine), and to melatonin (5-methoxy-N-acetyltryptamine), which plays a key role in daily human behavior. Moreover, TRA, and other indolic compounds are very efficient antioxidants. In this work the conformational space of TRA was scanned in aqueous solution, simulating the solvent by the polarizable continuum model. Geometry optimizations were performed at B3LYP/6-31+G** level. Electronic distributions were analyzed at a better calculation level, thus improving the basis set (6-311++G**). A topological study based on Bader’s theory (atoms in molecules) and natural bond orbital (NBO) framework was performed. Structural changes found in solution were related with charge delocalization mechanisms, which explained the changes in the conformational relative population in aqueous phase. Solvent effects on molecular electrostatic potential (MEPs) were also quantified and rationalized through charge delocalization mechanisms, thus connecting changes in MEPs with changes in structure, bond polarization, orbital bonding populations, natural charges, and bond topological properties. Moreover, polarizabilities and dipolar moments were calculated. All conformers were taken into account. Our results are the first prediction of TRA polarizabilities. The results reported contribute to the understanding of the structure, stability and reactivity of TRA and other indole derivatives.Centro de Química Inorgánic

Electronic structure and conformational properties of 1H-indole-3-acetic acid

The conformational space of 1H-Indole-3-Acetic Acid (IAA) was scanned using molecular dynamics at semiempirical level, and complemented with functional density calculations at B3LYP/6-31G**level, 14 conformers of lowest energy were obtained. Electronic distributions were analyzed at a higher calculation level, thus improving the basis set (B3LYP/6-311++G**). A topological study based on Bader's theory (AIM: atoms in molecules) and natural bond orbital (NBO) framework performed with the aim to analyze the stability and reactivity of the conformers allowed the understanding of electronic aspects relevant in the study of the antioxidant properties of IAA. Intramolecular hydrogen bonds were found and were characterized as blue-shifting hydrogen bonding interactions. Furthermore, molecular electrostatic potential maps (MEPs) were obtained and analyzed in the light of AIM and NBO results, thus showing subtle but essential features related not only to reactivity but also with intramolecular weak interactions, charge delocalization and structure stabilization. © 2010 Springer-Verlag.Fil: Pérez Schmit, María C.. Universidad de la Cuenca del Plata; ArgentinaFil: Jubert, Alicia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Vitale, Arturo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Programa de Radicales Libres; ArgentinaFil: Lobayan, Rosana Maria. Universidad de la Cuenca del Plata; Argentin