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1.
2.
Planta Med ; 84(12-13): 935-940, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29653457

RESUMO

Within the food and pharmaceutical industries, there is an increasing legislative requirement for the accurate labeling of the product's origin. A key feature of this is to indicate whether the product is of natural or synthetic origin. With reference to this context, we have investigated three alkaloids commonly exploited for human use: nicotine, atropine, and caffeine. We have measured by 13C nuclear magnetic resonance spectrometry the position-specific distribution of 13C at natural abundance within several samples of each of these target molecules. This technique is well suited to distinguishing between origins, as the distribution of the 13C isotope reflects the primary source of the carbon atoms and the process by which the molecule was (bio)synthesized. Our findings indicate that labeling can be misleading, especially in relation to a supplied compound being labeled as "synthetic" even though its 13C profile indicates a natural origin.


Assuntos
Alcaloides/análise , Espectroscopia de Ressonância Magnética/métodos , Alcaloides/metabolismo , Atropina/metabolismo , Cafeína/metabolismo , Isótopos de Carbono/análise , Nicotina/metabolismo
3.
Proc Natl Acad Sci U S A ; 112(27): 8296-301, 2015 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-26106160

RESUMO

Tramadol, previously only known as a synthetic analgesic, has now been found in the bark and wood of roots of the African medicinal tree Nauclea latifolia. At present, no direct evidence is available as to the biosynthetic pathway of its unusual skeleton. To provide guidance as to possible biosynthetic precursors, we have adopted a novel approach of retro-biosynthesis based on the position-specific distribution of isotopes in the extracted compound. Relatively recent developments in isotope ratio monitoring by (13)C NMR spectrometry make possible the measurement of the nonstatistical position-specific natural abundance distribution of (13)C (δ(13)Ci) within the molecule with better than 1‰ precision. Very substantial variation in the (13)C positional distribution is found: between δ(13)Ci = -11 and -53‰. Distribution is not random and it is argued that the pattern observed can substantially be interpreted in relation to known causes of isotope fractionation in natural products. Thus, a plausible biosynthetic scheme based on sound biosynthetic principals of precursor-substrate relationships can be proposed. In addition, data obtained from the (18)O/(16)O ratios in the oxygen atoms of the compound add support to the deductions made from the carbon isotope analysis. This paper shows how the use of (13)C NMR at natural abundance can help with proposing a biosynthetic route to compounds newly found in nature or those difficult to tackle by conventional means.


Assuntos
Vias Biossintéticas , Marcação por Isótopo/métodos , Espectroscopia de Ressonância Magnética/métodos , Tramadol/metabolismo , Carbono/metabolismo , Isótopos de Carbono/metabolismo , Espectrometria de Massas , Estrutura Molecular , Oxigênio/metabolismo , Isótopos de Oxigênio/metabolismo , Casca de Planta/química , Raízes de Plantas/química , Rubiaceae/química , Tramadol/química , Tramadol/isolamento & purificação , Madeira/química
4.
J Biol Chem ; 291(32): 16620-9, 2016 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-27288405

RESUMO

During the biosynthesis of natural products, isotopic fractionation occurs due to the selectivity of enzymes for the heavier or lighter isotopomers. As only some of the positions in the molecule are implicated in a given reaction mechanism, position-specific fractionation occurs, leading to a non-statistical distribution of isotopes. This can be accessed by isotope ratio monitoring (13)C NMR spectrometry. The solanaceous alkaloids S-(-)-nicotine and hyoscyamine (atropine) are related in having a common intermediate, but downstream enzymatic steps diverge, providing a relevant test case to: (a) elucidate the isotopic affiliation between carbon atoms in the alkaloids and those in the precursors; (b) obtain information about the kinetic isotope effects of as yet undescribed enzymes, thus to make predictions as to their possible mechanism(s). We show that the position-specific (13)C/(12)C ratios in the different moieties of these compounds can satisfactorily be related to their known precursors and to the known kinetic isotope effects of enzymes involved in their biosynthesis, or to similar reaction mechanisms. Thus, the pathway to the common intermediate, N-methyl-Δ(1)-pyrrolinium, is seen to introduce similar isotope distribution patterns in the two alkaloids independent of plant species, whereas the remaining atoms of each target compound, which are of different origins, reflect their specific metabolic ancestry. We further demonstrate that the measured (13)C distribution pattern can be used to deduce aspects of the reaction mechanism of enzymes still to be identified.


Assuntos
Nicotiana/metabolismo , Nicotina/biossíntese , Tropanos/metabolismo , Radioisótopos de Carbono/química , Nicotina/química , Nicotiana/química , Tropanos/química
5.
Arch Biochem Biophys ; 635: 60-65, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29074162

RESUMO

Many O-methyl and N-methyl groups in natural products are depleted in 13C relative to the rest of the molecule. These methyl groups are derived from the C-1 tetrahydrofolate pool via l-methionine, the principle donor of methyl units. Depletion could occur at a number of steps in the pathway. We have tested the hypothesis that methionine biosynthesis is implicated in this depletion by using a combined experimental and theoretical approach. By using isotope ratio monitoring 13C NMR spectrometry to measure the position-specific distribution of 13C within l-methionine of natural origin, it is shown that the S-methyl group is depleted in 13C by ∼20‰ relative to the other positions in the molecule. In parallel, we have conducted a basic theoretical analysis of the reaction pathway of methionine synthase to assess whether the enzyme cobalamin-independent l-methionine synthase (EC 2.1.1.14)-that catalyzes the synthesis of l-methionine from 5-methyl-tetrahydrofolate and homocysteine-plays a role in causing this depletion. Calculation predicts a strong normal 13C kinetic isotope effect (1.087) associated with this enzyme. Hence, depletion in 13C in the S-methyl of l-methionine during biosynthesis can be identified as an important factor contributing to the general depletion seen in many O-methyl and N-methyl groups of natural products.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/ultraestrutura , Isótopos de Carbono/química , Metionina/química , Nitrogênio/química , Oxigênio/química , Sítios de Ligação , Simulação por Computador , Ativação Enzimática , Metilação , Modelos Químicos , Modelos Moleculares , Ligação Proteica , Especificidade por Substrato
6.
Arthroscopy ; 33(6): 1159-1166, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28162917

RESUMO

PURPOSE: The primary purpose of this study was to determine the effect of the preoperative position of the musculotendinous junction (MTJ) on rotator cuff healing after double-row arthroscopic rotator cuff repair. A secondary purpose was to evaluate how tendon length and MTJ position change when the rotator cuff heals. METHODS: Preoperative and postoperative magnetic resonance imaging (MRI) scans of 42 patients undergoing arthroscopic double-row rotator cuff repair were reviewed. Patients undergoing repairs with other constructs or receiving augmented repairs (platelet-rich fibrin matrix) who had postoperative MRI scans were excluded. Preoperative MRI scans were evaluated for anteroposterior tear size, tendon retraction, tendon length, muscle quality, and MTJ position with respect to the glenoid in the coronal plane. The position of the MTJ was referenced off the glenoid face as either lateral or medial. Postoperative MRI scans were evaluated for healing, tendon length, and MTJ position. RESULTS: Of 42 tears, 36 (86%) healed, with 27 of 31 small to medium tears (87%) and 9 of 11 large to massive tears (82%) healing. Healing occurred in 94% of tears that had a preoperative MTJ lateral to the face of the glenoid but only 56% of tears that had a preoperative MTJ medial to the glenoid face (P = .0135). The measured tendon length increased an average of 14.4 mm in patients whose tears healed compared with shortening by 6.4 mm in patients with tears that did not heal (P < .001). The MTJ lateralized an average of 6.1 mm in patients whose tears healed compared with medializing 1.9 mm in patients whose tears did not heal (P = .026). The overall follow-up period of the study was from April 2005 to September 2014 (113 months). CONCLUSIONS: The preoperative MTJ position is predictive of postoperative healing after double-row rotator cuff repair. The position of the MTJ with respect to the glenoid face is a reliable, identifiable marker on MRI scans that can be predictive of healing. LEVEL OF EVIDENCE: Level IV, retrospective review of case series; therapeutic study.


Assuntos
Lesões do Manguito Rotador/fisiopatologia , Manguito Rotador/fisiopatologia , Técnicas de Sutura , Adulto , Artroscopia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Estudos Retrospectivos , Manguito Rotador/diagnóstico por imagem , Manguito Rotador/cirurgia , Lesões do Manguito Rotador/diagnóstico por imagem , Lesões do Manguito Rotador/cirurgia , Resultado do Tratamento , Cicatrização
7.
J Biol Chem ; 290(7): 4118-28, 2015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25538251

RESUMO

During the anaerobic fermentation of glucose to ethanol, the three micro-organisms Saccharomyces cerevisiae, Zymomonas mobilis, and Leuconostoc mesenteroides exploit, respectively, the Embden-Meyerhof-Parnas, the Entner-Doudoroff, and the reductive pentose phosphate pathways. Thus, the atoms incorporated into ethanol do not have the same affiliation to the atomic positions in glucose. The isotopic fractionation occurring in each pathway at both the methylene and methyl positions of ethanol has been investigated by isotopic quantitative (13)C NMR spectrometry with the aim of observing whether an isotope redistribution characteristic of the enzymes active in each pathway can be measured. First, it is found that each pathway has a unique isotope redistribution signature. Second, for the methylene group, a significant apparent kinetic isotope effect is only found in the reductive pentose phosphate pathway. Third, the apparent kinetic isotope effects related to the methyl group are more pronounced than for the methylene group. These findings can (i) be related to known kinetic isotope effects of some of the enzymes concerned and (ii) give indicators as to which steps in the pathways are likely to be influencing the final isotopic composition in the ethanol.


Assuntos
Radioisótopos de Carbono/farmacocinética , Etanol/metabolismo , Fermentação/fisiologia , Glucose/metabolismo , Leuconostoc/metabolismo , Redes e Vias Metabólicas/fisiologia , Saccharomyces cerevisiae/metabolismo , Zymomonas/metabolismo , Glicólise , Espectroscopia de Ressonância Magnética , Via de Pentose Fosfato , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Distribuição Tecidual
8.
Nat Prod Rep ; 33(9): 1034-43, 2016 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-27346294

RESUMO

Covering up to 2016Nauclea latifolia (syn. Sarcocephalus latifolius, Rubiaceae), commonly called the African pincushion tree, is a plant widely used in folk medicine in different regions of Africa for treating a variety of illnesses, including malaria, epilepsy and pain. N. latifolia has not only drawn the interest of traditional healers but also of phytochemists, who have identified a range of bioactive indole alkaloids in its tissue. More recently, following up on the traditional use of extracts in pain management, a bio-guided purification from the roots of the tree led to the identification of the active ingredient as tramadol, available as a synthetic analgesic since the 1970s. The discovery of this compound as a natural phytochemical was highlighted worldwide. This review focuses on the correlation between extracted compounds and pharmacological activities, paying special attention to infectious diseases and neurologically-related disorders. A critical analysis of the data reported so far on the natural origin of tramadol and its proposed biosynthesis is also presented.


Assuntos
Alcaloides Indólicos , Rubiaceae/química , Tramadol/farmacologia , Árvores/química , Analgésicos Opioides/uso terapêutico , Animais , Alcaloides Indólicos/química , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Malária/tratamento farmacológico , Medicina Tradicional , Estrutura Molecular , Raízes de Plantas/química , Tramadol/química , Tramadol/isolamento & purificação , Tramadol/metabolismo
9.
Planta Med ; 82(11-12): 967-72, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27224268

RESUMO

The seeds of Carapa procera are exploited extensively in West African ethnopharmacy for the treatment of several pathologies, including inflammation. They also are effective as insect antifeedants and as a mosquito repellent. With the aim of identifying bioactive principles, an ethyl acetate extract of the defatted seeds was made and fractionated. Two principle compounds were isolated. One of these, 5,6-dehydro-7-deacetoxy-7-oxogedunin (1), while known from another genus of the Meliaceae, is newly identified from the genus Carapa and its X-ray structure is described for the first time. In addition, 1 displayed strong anti-clonogenic activity at 10 µM. The other compound, mexicanolide (2), is known from this species and showed neither cytotoxicity nor anti-clonogenicity. These differences in efficacy are discussed in relation to known structure-activity relationships of limonoids.


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Limoninas/isolamento & purificação , Meliaceae/química , Extratos Vegetais/isolamento & purificação , Triterpenos/isolamento & purificação , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Limoninas/química , Limoninas/farmacologia , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Sementes/química , Triterpenos/química , Triterpenos/farmacologia
10.
Anal Chem ; 87(15): 7550-4, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26158226

RESUMO

The intramolecular (13)C composition of a molecule retains evidence relevant to its (bio)synthetic history and can provide valuable information in numerous fields ranging from biochemistry to environmental sciences. Isotope ratio monitoring by (13)C NMR spectrometry (irm-(13)C NMR) is a generic method that offers the potential to conduct (13)C position-specific isotope analysis with a precision better than 1‰. Until now, determining absolute values also required measurement of the global (or bulk) (13)C composition (δ(13)Cg) by mass spectrometry. In a radical new approach, it is shown that an internal isotopic chemical reference for irm-(13)C NMR can be used instead. The strategy uses (1)H NMR to quantify both the number of moles of the reference and of the studied compound present in the NMR tube. Thus, the sample preparation protocol is greatly simplified, bypassing the previous requirement for precise purity and mass determination. The key to accurate results is suppressing the effect of radiation damping in (1)H NMR which produces signal distortion and alters quantification. The methodology, applied to vanillin with dimethylsulfone as an internal standard, has an equivalent accuracy (<1‰) to that of the conventional approach. Hence, it was possible to clearly identify vanillin from different origins based on the (13)C isotopic profiles.

11.
Anal Chem ; 87(13): 6600-6, 2015 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-26067163

RESUMO

The natural xanthines caffeine, theobromine, and theophylline are of major commercial importance as flavor constituents in coffee, cocoa, tea, and a number of other beverages. However, their exploitation for authenticity, a requirement in these commodities that have a large origin-based price-range, by the standard method of isotope ratio monitoring by mass spectrometry (irm-MS) is limited. We have now developed a methodology that overcomes this deficit that exploits the power of isotopic quantitative (13)C nuclear magnetic resonance (NMR) spectrometry combined with chemical modification of the xanthines to enable the determination of positional intramolecular (13)C/(12)C ratios (δ(13)Ci) with high precision. However, only caffeine is amenable to analysis: theobromine and theophylline present substantial difficulties due to their poor solubility. However, their N-methylation to caffeine makes spectral acquisition feasible. The method is confirmed as robust, with good repeatability of the δ(13)Ci values in caffeine appropriate for isotope fractionation measurements at natural abundance. It is shown that there is negligible isotope fractionation during the chemical N-methylation procedure. Thus, the method preserves the original positional δ(13)Ci values. The method has been applied to measure the position-specific variation of the (13)C/(12)C distribution in caffeine. Not only is a clear difference between caffeine isolated from different sources observed, but theobromine from cocoa is found to show a (13)C pattern distinct from that of caffeine.


Assuntos
Espectroscopia de Ressonância Magnética Nuclear de Carbono-13/métodos , Xantinas/química , Metilação
12.
Environ Sci Technol ; 49(21): 12782-8, 2015 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-26443423

RESUMO

Position-specific isotope effects (PSIEs) have been measured by isotope ratio monitoring (13)C nuclear magnetic resonance spectrometry during the evaporation of 10 liquids of different polarities under 4 evaporation modes (passive evaporation, air-vented evaporation, low pressure evaporation, distillation). The observed effects are used to assess the validity of the Craig-Gordon isotope model for organic liquids. For seven liquids the overall isotope effect (IE) includes a vapor-liquid contribution that is strongly position-specific in polar compounds but less so in apolar compounds and a diffusive IE that is not position-specific, except in the alcohols, ethanol and propan-1-ol. The diffusive IE is diminished under forced evaporation. The position-specific isotope pattern created by liquid-vapor IEs is manifest in five liquids, which have an air-side limitation for volatilization. For the alcohols, undefined processes in the liquid phase create additional PSIEs. Three other liquids with limitations on the liquid side have a lower, highly position-specific, bulk diffusive IE. It is concluded that evaporation of organic pollutants creates unique position-specific isotope patterns that may be used to assess the progress of remediation or natural attenuation of pollution and that the Craig-Gordon isotope model is valid for the volatilization of nonpolar organic liquids with air-side limitation of the volatilization rate.


Assuntos
Isótopos de Carbono/análise , Modelos Teóricos , Acetona/química , Isótopos de Carbono/química , Meio Ambiente , Gases , Heptanos/química , Hidrocarbonetos Bromados/química , Metanol/química , Éteres Metílicos/química , Modelos Químicos , Compostos Orgânicos/análise , Compostos Orgânicos/química , Pressão , Volatilização
13.
Proc Natl Acad Sci U S A ; 109(44): 18204-9, 2012 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-23074255

RESUMO

The stable carbon isotope (13)C is used as a universal tracer in plant eco-physiology and studies of carbon exchange between vegetation and atmosphere. Photosynthesis fractionates against (13)CO(2) so that source sugars (photosynthates) are on average (13)C depleted by 20‰ compared with atmospheric CO(2). The carbon isotope distribution within sugars has been shown to be heterogeneous, with relatively (13)C-enriched and (13)C-depleted C-atom positions. The (13)C pattern within sugars is the cornerstone of (13)C distribution in plants, because all metabolites inherit the (13)C abundance in their specific precursor C-atom positions. However, the intramolecular isotope pattern in source leaf glucose and the isotope fractionation associated with key enzymes involved in sugar interconversions are currently unknown. To gain insight into these, we have analyzed the intramolecular isotope composition in source leaf transient starch, grain storage starch, and root storage sucrose and measured the site-specific isotope fractionation associated with the invertase (EC 3.2.1.26) and glucose isomerase (EC 5.3.1.5) reactions. When these data are integrated into a simple steady-state model of plant isotopic fluxes, the enzyme-dependent fractionations satisfactorily predict the observed intramolecular patterns. These results demonstrate that glucose and sucrose metabolism is the primary determinant of the (13)C abundance in source and sink tissue and is, therefore, of fundamental importance to the interpretation of plant isotopic signals.


Assuntos
Isótopos de Carbono/análise , Hexoses/química , Plantas/química , Cromatografia Líquida de Alta Pressão , Modelos Teóricos , Fotossíntese , Folhas de Planta/química
14.
Amino Acids ; 45(6): 1365-72, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24072506

RESUMO

Since exclusively breast-suckled infants obtain their nutrient only from their mother's milk, it might be anticipated that a correlation will exist between the (15)N/(14)N isotope ratios of amino acids of protein of young infants and those supplied by their mother. The work presented here aimed to determine whether amino nitrogen transfer from human milk to infant hair protein synthesized within the first month of life conserves the maternal isotopic signature or whether post-ingestion fractionation dominates the nitrogen isotope spectrum. The study was conducted at 1 month post-birth on 100 mother-infant pairs. Isotope ratios (15)N/(14)N and (13)C/(12)C were measured using isotope ratio measurement by Mass Spectrometry (irm-MS) for whole maternal milk, and infant hair and (15)N/(14)N ratios were also measured by GC-irm-MS for the N-pivaloyl-O-isopropyl esters of amino acids obtained from the hydrolysis of milk and hair proteins. The δ(15)N and δ(13)C (‰) were found to be significantly higher in infant hair than in breast milk (δ(15)N, P < 0.001; δ(13)C, P < 0.001). Furthermore, the δ(15)N (‰) of individual amino acids in infant hair was also significantly higher than that in maternal milk (P < 0.001). By calculation, the observed shift in isotope ratio was shown not to be accounted for by the amino acid composition of hair and milk proteins, indicating that it is not simply due to differences in the composition in the proteins present. Rather, it would appear that each pool-mother and infant-turns over independently, and that fractionation in infant N-metabolism even in the first month of life dominates over the nutrient N-content.


Assuntos
Aminoácidos/análise , Cabelo/química , Proteínas do Leite/química , Leite Humano/química , Adulto , Feminino , Humanos , Lactente , Isótopos de Nitrogênio/análise
15.
Rapid Commun Mass Spectrom ; 27(12): 1345-53, 2013 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-23681812

RESUMO

RATIONALE: In isotope tracer experiments used in nutritional studies, it is frequently desirable both to determine the (15)N/(14)N ratios of target compounds and to quantify these compounds. This report shows how this can be achieved in a single chromatographic run for protein amino acids using an isotope ratio mass spectrometer. METHODS: Protein hydrolysis by acidic digestion was used to release amino acids, which were then derivatized as their N-pivaloyl-O-isopropyl esters. Suitable conditions for sample preparation were established for both hair and milk proteins. The N-pivaloyl-O-isopropyl esters of amino acids were separated by gas chromatography (GC) on a 60 m ZB-WAX column linked via a combustion interface to an isotope ratio mass spectrometer. The (15)N/(14)N ratios were obtained from the m/z 28, 29 and 30 peak intensities and the quantities from the Area All (Vs) integrated peak areas. RESULTS: It is shown from a five-point calibration curve that both parameters can be measured reliably within the range of 1.0 to 2.0 mg/mL for the major amino acids derived from the hydrolysis of human maternal milk or hair samples. The method was validated in terms of inter-day and inter-user repeatability for both parameters for 14 amino acids. The amino acid percentage composition showed a good correlation with literature values. The method was applied to determine the variability in a population of lactating mothers and their infants. CONCLUSIONS: It has been established that δ(15)N values can be simultaneously determined for a complex mixture of amino acids at variable concentrations. It is shown that the percentage composition obtained correlates well with that obtained by calculation from the protein composition or from literature values. This procedure should provide a significant saving in analysis time, especially in those cases where the GC run-time is necessarily long. It allows the satisfactory determination of the variation within a sample population.


Assuntos
Aminoácidos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Cabelo/química , Leite Humano/química , Isótopos de Nitrogênio/análise , Proteínas/química , Adulto , Feminino , Humanos , Lactente , Lactação , Masculino , Adulto Jovem
16.
Phytother Res ; 27(6): 835-40, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22899281

RESUMO

The leaves of Chromolaena odorata (Asteraceae) are exploited extensively in West and Central African ethnopharmacy for the treatment of a wide range of conditions, despite this being a non-native species established in the last 50 years. With the objective of seeking bioactive principles, the nonvolatile compounds, an ethanolic (80% v/v) extract was made and fractionated. From the hexane-soluble fraction, three compounds were isolated. Two of these, 5-hydroxy-7,4'-dimethoxyflavanone and 2'-hydroxy-4,4',5',6'-tetramethoxychalcone, have previously been identified in C. odorata leaves. The third was fully characterised spectroscopically and found to be 1,6-dimethyl-4-(1-methylethyl)naphthalene (cadalene), not previously isolated from the Asteraceae. All three compounds were tested for their cytotoxicity and anticancer properties. 2'-Hydroxy-4,4',5',6'-tetramethoxychalcone was found to be both cytotoxic and anticlonogenic at 20 µm in cell lines Cal51, MCF7 and MDAMB-468, and to act synergistically with the Bcl2 inhibitor ABT737 to enhance apoptosis in Cal51 breast cancer cells.


Assuntos
Apoptose/efeitos dos fármacos , Chromolaena/química , Extratos Vegetais/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Chalconas/química , Chalconas/farmacologia , Flavanonas/química , Flavanonas/farmacologia , Humanos , Naftalenos/química , Naftalenos/farmacologia , Extratos Vegetais/química , Folhas de Planta/química
17.
Nat Prod Rep ; 29(4): 476-86, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22337171

RESUMO

This paper discusses the biochemical and physiological factors underlying the site-specific, non-random distribution of ¹³C/¹²C isotope ratios within plant metabolites, which can be determined by isotopic ¹³C NMR spectrometry. It focuses on the key metabolite glucose and on enzyme activities and physiological processes that are responsible for the carbon isotope patterns in glucose from different biological origins. It further considers how intramolecular ¹³C/¹²C isotope ratios in glucose can be exploited to understand fundamental aspects of plant biological chemistry, how these are related to environmental parameters and how these influence metabolites beyond central sugar metabolism. It does not purport to be an extensive overview of intramolecular isotopic patterns. Rather, the aim is to show how a full understanding of ¹³C/¹²C fractionations occurring during plant metabolism can only be possible once the factors that define intramolecular isotope values are better delineated.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Sacarose/química , Isótopos de Carbono/análise , Estrutura Molecular , Sacarose/análise
18.
Pediatr Res ; 71(5): 598-604, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22398698

RESUMO

INTRODUCTION: Protein intake in fetal life or infancy may play a key role in determining early growth rate, a determinant of later health and disease. Previous work has indicated that hair isotopic composition is influenced by diet and protein intake. METHODS: This study analyzes the isotopic composition of hair obtained from 239 mother/newborn pairs randomly selected within a larger cohort enrolled in a study of pre- and postnatal determinants of the child's development and health. The isotopic compositions in nitrogen (δ(15)N) and in carbon (δ(13)C) were determined by isotope ratio mass spectrometry. RESULTS: Mother and newborn hair δ(15)N were tightly correlated (Pearson r = 0.88). The mean δ(15)N and δ(13)C values of hair from newborn infants were significantly higher than those for the mothers: 9.7 ± 0.7 vs. 8.8 ± 0.6‰ (P < 0.0001) for δ(15)N and -20.0 ± 0.4 vs. -20.4 ± 0.4‰ (P < 0.0001) for δ(13)C. Maternal hair δ(15)N at parturition was slightly and positively correlated with estimates of protein intake (r = 0.14, P = 0.04). DISCUSSION: Hair δ(15)N of the fetus is both highly dependent on and systematically higher than that of the mother. Whether quantitative and qualitative protein intake, disease, or hormonal status alter hair δ(15)N at birth remains to be determined.


Assuntos
Isótopos de Carbono/análise , Cabelo/química , Isótopos de Nitrogênio/análise , Adulto , Estudos de Coortes , Feminino , Humanos , Recém-Nascido , Masculino , Espectrometria de Massas
19.
Anal Bioanal Chem ; 402(9): 2985-98, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22349323

RESUMO

Natural abundance deuterium 2D NMR spectroscopy in weakly ordering, polypeptide chiral liquid crystals is a powerful technique that enables determination of enantiotopic isotopic ratios ((2)H/(1)H)( i ) at the methylene groups of long-chain fatty acids. This technique has been used to study the bioconversion of linoleic acid to vernoleic acid with the objective of establishing the in-vivo site-specific fractionation of (2)H associated with this process. The fractionation pattern was investigated in Euphorbia lagascae and Vernonia galamensis, plants that use different enzyme systems to perform the Δ(12)-epoxidation: a cytochrome P450 monooxygenase in the former and a di-iron dioxygenase in the latter. The specific interest in this study was to ascertain whether different ((2)H/(1)H)( i ) isotopic ratios in substrate and product might reflect distinct features of the nature of the reaction centre. However, both the linoleate (substrate) samples and both vernoleate (product) samples isolated from the seed oils of the two plants had remarkably similar (2)H isotope profiles, with selection against (2)H in the positions around the Δ(12)-epoxidation site. This is interpreted as indicating that, despite differences in the form in which the activated Fe is presented and in the architecture of the active site, the ((2)H/(1)H)( i ) isotopic pattern is determined by features common to the reaction. It is suggested that the effects acting as the overall determinants of the final ((2)H/(1)H)( i ) distribution in the product are the encumbrance of the active site pocket and constraints to conformational readjustment during the linoleate to vernoleate transformation.


Assuntos
Sistema Enzimático do Citocromo P-450/química , Dioxigenases/química , Compostos de Epóxi/química , Euphorbia/enzimologia , Ácido Linoleico/química , Espectroscopia de Ressonância Magnética/métodos , Ácidos Oleicos/química , Óleos de Plantas/química , Proteínas de Plantas/química , Vernonia/enzimologia , Sistema Enzimático do Citocromo P-450/metabolismo , Deutério/química , Dioxigenases/metabolismo , Cristais Líquidos/química , Estrutura Molecular , Oxirredução , Proteínas de Plantas/metabolismo , Solventes/química , Especificidade por Substrato
20.
Mil Med ; 187(3-4): e282-e289, 2022 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-33242087

RESUMO

INTRODUCTION: Musculoskeletal injuries are an endemic amongst U.S. Military Service Members and significantly strain the Department of Defense's Military Health System. The Military Health System aims to provide Service Members, military retirees, and their families the right care at the right time. The Military Orthopedics Tracking Injuries and Outcomes Network (MOTION) captures the data that can optimize musculoskeletal care within the Military Health System. This report provides MOTION structural framework and highlights how it can be used to optimize musculoskeletal care. MATERIALS AND METHODS: MOTION established an internet-based data capture system, the MOTION Musculoskeletal Data Portal. All adult Military Health System patients who undergo orthopedic surgery are eligible for entry into the database. All data are collected as routine standard of care, with patients and orthopedic surgeons inputting validated global and condition-specific patient reported outcomes and operative case data, respectively. Patients have the option to consent to allow their standard of care data to be utilized within an institutional review board approved observational research study. MOTION data can be merged with other existing data systems (e.g., electronic medical record) to develop a comprehensive dataset of relevant information. In pursuit of enhancing musculoskeletal injury patient outcomes MOTION aims to: (1) identify factors which predict favorable outcomes; (2) develop models which inform the surgeon and military commanders if patients are behind, on, or ahead of schedule for their targeted return-to-duty/activity; and (3) develop predictive models to better inform patients and surgeons of the likelihood of a positive outcome for various treatment options to enhance patient counseling and expectation management. RESULTS: This is a protocol article describing the intent and methodology for MOTION; thus, to date, there are no results to report. CONCLUSIONS: MOTION was established to capture the data that are necessary to improve military medical readiness and optimize medical resource utilization through the systematic evaluation of short- and long-term musculoskeletal injury patient outcomes. The systematic enhancement of musculoskeletal injury care through data analyses aligns with the National Defense Authorization Act (2017) and Defense Health Agency's Quadruple Aim, which emphasizes optimizing healthcare delivery and Service Member medical readiness. This transformative approach to musculoskeletal care can be applied across disciplines within the Military Health System.


Assuntos
Serviços de Saúde Militar , Militares , Doenças Musculoesqueléticas , Sistema Musculoesquelético , Ortopedia , Adulto , Humanos , Doenças Musculoesqueléticas/epidemiologia , Doenças Musculoesqueléticas/terapia , Sistema Musculoesquelético/lesões
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