RESUMO
2-Hydroxy-3-pentanone and 3-hydroxy-2-pentanone are flavor molecules present in various foods, such as cheese, wine, durian, and honey, where they impart buttery, hay-like, and caramel-sweet aromas. However, their utilization as flavoring agents is constrained by a lack of developed synthesis methods. In this study, we present their synthesis from simple starting compounds available in natural quality, catalyzed by previously characterized ThDP-dependent carboligases. Additionally, we demonstrate that newly discovered homologues of pyruvate dehydrogenase from E. coli (EcPDH E1), namely LaPDH from Leclercia adecarboxylata, CnPDH from Cupriavidus necator, and TcPDH from Tanacetum cinerariifolium, exhibit promising potential for α-hydroxy pentanone synthesis in form of whole-cell biocatalysts. Enzyme stability at varying pH levels, kinetic parameters, and reaction intensification were investigated. CnPDH, for example, exhibits superior stability across different pH levels compared to EcPDH E1. Both α-hydroxy pentanones can be produced with CnPDH in satisfactory yields (74% and 59%, respectively).
Assuntos
Pentanonas , Pentanonas/metabolismo , Pentanonas/química , Escherichia coli/metabolismo , Aromatizantes/metabolismo , Aromatizantes/química , Cinética , Concentração de Íons de HidrogênioRESUMO
We here report a manganese-based oxidative cleavage of inactivated acetylacetonate, the mechanistic pathway of which resembles Dke1-catalyzed reactions of ß-diketone and α-keto acid. This oxidative transformation proceeds through an acetylacetonate-pyruvate-oxalate pathway, which can be terminated at the stage of pyruvate through ligand/solvent variation. XRD, time-dependent GC-MS, and isotope-labeling studies suggested that our system represents the same cleaving specificity and dioxygenase-like reactivity of Dke1.
Assuntos
Dioxigenases/metabolismo , Hidroxibutiratos/metabolismo , Cetonas/metabolismo , Manganês/metabolismo , Pentanonas/metabolismo , Dioxigenases/química , Hidroxibutiratos/química , Cetonas/química , Manganês/química , Estrutura Molecular , Pentanonas/químicaRESUMO
Cathinone derivatives are the most representative group within new drugs market, which have been described as neurotoxic. Since cathinones, as pentedrone and methylone, are available as racemates, it is our aim to study the neuronal cytotoxicity induced by each enantiomer. Therefore, a dopaminergic SH-SY5Y cell line was used to evaluate the hypothesis of enantioselectivity of pentedrone and methylone enantiomers on cytotoxicity, oxidative stress, and membrane efflux transport (confirmed by in silico studies). Our study demonstrated enantioselectivity of these cathinones, being the S-(+)-pentedrone and R-(+)-methylone the most oxidative enantiomers and also the most cytotoxic, suggesting the oxidative stress as main cytotoxic mechanism, as previously described in in vitro studies. Additionally, the efflux transporter multidrug resistance associated protein 1 (MRP1) seems to play, together with GSH, a selective protective role against the cytotoxicity induced by R-(-)-pentedrone enantiomer. It was also observed an enantioselectivity in the binding to P-glycoprotein (P-gp), another efflux protein, being the R-(-)-pentedrone and S-(-)-methylone the most transported enantiomeric compounds. These results were confirmed, in silico, by docking studies, revealing that R-(-)-pentedrone is the enantiomer with highest affinity to MRP1 and S-(-)-methylone and R-(-)-pentedrone are the enantiomers with highest affinity to P-gp. In conclusion, our data demonstrated that pentedrone and methylone present enantioselectivity in their cytotoxicity, which seems to involve different oxidative reactivity as well as different affinity to the P-gp and MRP1 that together with GSH play a protective role.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Alcaloides/toxicidade , Neurônios Dopaminérgicos/efeitos dos fármacos , Metanfetamina/análogos & derivados , Metilaminas/toxicidade , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pentanonas/toxicidade , Alcaloides/química , Alcaloides/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Relação Dose-Resposta a Droga , Glutationa/metabolismo , Humanos , Metanfetamina/química , Metanfetamina/metabolismo , Metanfetamina/toxicidade , Metilaminas/química , Metilaminas/metabolismo , Simulação de Acoplamento Molecular , Pentanonas/química , Pentanonas/metabolismo , Ligação Proteica , EstereoisomerismoRESUMO
NFAT-133 is a Streptomyces-derived aromatic polyketide compound with immunosuppressive, antidiabetic, and antitrypanosomal activities. It inhibits transcription mediated by nuclear factor of activated T cells (NFAT), leading to the suppression of interleukin-2 expression and T cell proliferation. It also activates the AMPK pathway in L6 myotubes and increases glucose uptake. In addition to NFAT-133, a number of its congeners, e.g., panowamycins and benwamycins, have been identified. However, little is known about their modes of formation in the producing organisms. Through genome sequencing of Streptomyces pactum ATCC 27456, gene inactivation, and genetic complementation experiments, the biosynthetic gene cluster of NFAT-133 and its congeners has been identified. The cluster contains a highly disordered genetic organization of type I modular polyketide synthase genes with several genes that are necessary for the formation of the aromatic core unit and tailoring processes. In addition, a number of new analogs of NFAT-133 were isolated and their chemical structures elucidated. It is suggested that the heptaketide NFAT-133 is derived from an octaketide intermediate, TM-123. The current study shows yet another unusual biosynthetic pathway involving a noncanonical polyketide synthase assembly line to produce a group of small molecules with valuable bioactivities.
Assuntos
Pentanóis/metabolismo , Pentanonas/metabolismo , Streptomyces/metabolismo , Biologia Computacional , Genes Bacterianos , Genoma Bacteriano , Espectroscopia de Ressonância Magnética , Família Multigênica , Policetídeo Sintases/genética , Streptomyces/enzimologia , Streptomyces/genéticaRESUMO
Dimethyl trisulfide (DMTS) is one of the main components responsible for hineka, the aroma associated with deteriorated Japanese sake during storage. The molecule 1,2-dihydroxy-5-(methylsulfinyl)pentan-3-one (DMTS-P1) has been previously identified as a major precursor compound of DMTS. Furthermore, it had been suggested that the yeast methionine salvage pathway is involved in the production of DMTS-P1. In sake brewing tests, DMTS-P1 and the DMTS producing potential (DMTS-pp; DMTS amount of sake after accelerated storage) were significantly reduced in mde1 or mri1 strain, which lack genes of the methionine salvage pathway. Industrial use of the gene-disrupting strains may not be accepted in the Japanese food industry. In order to obtain mde1 or mri1 mutants, we established a method to screen 5'-methylthioadenosine (MTA) non-utilizing strains using minimum culture medium containing methionine or MTA by ethyl methanesulfonate (EMS) mutagenesis with methionine-auxotrophic sake yeast haploid. As expected, mde1 and mri1 mutants were identified among the obtained mutants by an established screening method. The obtained strains had poor fermentation ability in sake brewing tests, so back-crossing was performed on the mutants to obtain mde1 or mri1 homozygous mutants. These strains had improved brewing characteristics, and DMTS-P1 and the DMTS-pp of the produced sake were significantly lower than those of the parent strains. These strains are expected to contribute to improving the maintenance of sake quality during storage.
Assuntos
Bebidas Alcoólicas/microbiologia , Hibridização Genética , Mutagênese , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Sulfetos/metabolismo , Fermentação , Haploidia , Odorantes/análise , Pentanonas/metabolismoRESUMO
The mechanism leading to aroma persistence during eating is not fully described. This study aims at better understanding the role of the oral mucosa in this phenomenon. Release of 14 volatile compounds from different chemical classes was studied after exposure to in vitro models of oral mucosa, at equilibrium by Gas-Chromatography-Flame Ionization Detection (GC-FID) and in dynamic conditions by Proton Transfer Reaction- Mass Spectrometry (PTR-MS). Measurements at equilibrium showed that mucosal hydration reduced the release of only two compounds, pentan-2-one and linalool (p < 0.05), and suggested that cells could metabolize aroma compounds from different chemical families (penta-2,3-dione, trans-2-hexen-1-al, ethyl hexanoate, nonan- and decan-2-one). Dynamic analyses for pentan-2-one and octan-2-one evidenced that the constituents of the mucosal pellicle influenced release kinetics differently depending on molecule hydrophobicity. This work suggests that mucosal cells can metabolize aroma compounds and that non-covalent interactions occur between aroma compounds and oral mucosa depending on aroma chemical structure.
Assuntos
Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/metabolismo , Odorantes , Compostos Orgânicos Voláteis/análise , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/metabolismo , Ingestão de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Odorantes/análise , Pentanonas/análise , Pentanonas/metabolismo , SalivaRESUMO
Polyhydroxylated compounds are building blocks for the synthesis of carbohydrates and other natural products. Their synthesis is mainly achieved by different synthetic versions of aldol-coupling reactions, catalyzed either by organocatalysts, enzymes, or metal-organic catalysts. We have investigated the formation of 1,4-substituted 2,3-dihydroxybutan-1-one derivatives from para- and meta-substituted phenylacetaldehydes by three distinctly different strategies. The first involved a direct aldol reaction with hydroxyacetone, dihydroxyacetone, or 2-hydroxyacetophenone, catalyzed by the cinchona derivative cinchonine. The second was reductive cross-coupling with methyl- or phenylglyoxal promoted by SmI2, resulting in either 5-substituted 3,4-dihydroxypentan-2-ones or 1,4 bis-phenyl-substituted butanones, respectively. Finally, in the third case, aldolase catalysis was employed for synthesis of the corresponding 1,3,4-trihydroxylated pentan-2-one derivatives. The organocatalytic route with cinchonine generated distereomerically enriched syn-products (de = 60-99%), with moderate enantiomeric excesses (ee = 43-56%) but did not produce aldols with either hydroxyacetone or dihydroxyacetone as donor ketones. The SmI2-promoted reductive cross-coupling generated product mixtures with diastereomeric and enantiomeric ratios close to unity. This route allowed for the production of both 1-methyl- and 1-phenyl-substituted 2,3-dihydroxybutanones at yields between 40-60%. Finally, the biocatalytic approach resulted in enantiopure syn-(3 R,4 S) 1,3,4-trihydroxypentan-2-ones.
Assuntos
Butanonas/síntese química , Butanonas/metabolismo , Cinchona/química , Frutose-Bifosfato Aldolase/metabolismo , Pentanonas/síntese química , Pentanonas/metabolismo , Butanonas/química , Catálise , Estrutura Molecular , Pentanonas/química , EstereoisomerismoRESUMO
A new protocol based on lipase-catalyzed tandem reaction toward α,ß-enones/enoesters is presented. For the synthesis of the desired products the tandem process based on enzyme-catalyzed hydrolysis and Knoevenagel reaction starting from enol acetates and aldehyde is developed. The relevant impact of the reaction conditions including organic solvent, enzyme type, and temperature on the course of the reaction was revealed. It was shown that controllable release of the active methylene compound from the corresponding enol carboxylate ensured by enzymatic reaction diminishes significantly the formation of the unwanted co-products. Furthermore, this protocol was extended by including a second tandem chemoenzymatic transformation engaging various aldehyde precursors. After a careful optimization of the reaction conditions, the target products were obtained with yields up to 86 % and with excellent E/Z-selectivity.
Assuntos
Aldeídos/metabolismo , Lipase/metabolismo , Aldeídos/química , Animais , Biocatálise , Hidrólise , Lipase/química , Pancrelipase/metabolismo , Pentanonas/química , Pentanonas/metabolismo , Estereoisomerismo , SuínosRESUMO
Quorum sensing (QS) regulates population-dependent bacterial behaviours, such as toxin production, biofilm formation and virulence. Autoinducer-2 (AI-2) is to date the only signalling molecule known to foster inter-species bacterial communication across distantly related bacterial species. In this work, the synthesis of pure enantiomers of C4-propoxy-HPD and C4-ethoxy-HPD, known AI-2 analogues, has been developed. The optimised synthesis is efficient, reproducible and short. The (4S) enantiomer of C4-propoxy-HPD was the most active compound being approximately twice as efficient as (4S)-DPD and ten-times more potent than the (4R) enantiomer. Additionally, the specificity of this analogue to bacteria with LuxP receptors makes it a good candidate for clinical applications, because it is not susceptible to scavenging by LsrB-containing bacteria that degrade the natural AI-2. All in all, this study provides a new brief and effective synthesis of isomerically pure analogues for QS modulation that include the most active AI-2 agonist described so far.
Assuntos
Antibacterianos/farmacologia , Pentanonas/farmacologia , Percepção de Quorum/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Escherichia coli/fisiologia , Proteínas de Escherichia coli/metabolismo , Pentanonas/síntese química , Pentanonas/metabolismo , Estereoisomerismo , Vibrio/fisiologiaRESUMO
RATIONALE: New psychoactive substances (NPSs), including substituted cathinones and other stimulants, are synthesized, sold on the Internet, and ingested without knowledge of their pharmacological activity and/or toxicity. In vitro pharmacology plays a role in therapeutic drug development, drug-protein in silico interaction modeling, and drug scheduling. OBJECTIVES: The goal of this research was to determine mechanisms of action that may indicate NPS abuse liability. METHODS: Affinities to displace the radioligand [125I]RTI-55 and potencies to inhibit [3H]neurotransmitter uptake for 22 cathinones, 6 benzofurans and another stimulant were characterized using human embryonic kidney cells stably expressing recombinant human transporters for dopamine, norepinephrine, or serotonin (hDAT, hNET, or hSERT, respectively). Selected compounds were tested for potencies and efficacies at inducing [3H]neurotransmitter release via the transporters. Computational modeling was conducted to explain plausible molecular interactions established by NPS and transporters. RESULTS: Most α-pyrrolidinophenones had high hDAT potencies and selectivities in uptake assays, with hDAT/hSERT uptake selectivity ratios of 83-360. Other substituted cathinones varied in their potencies and selectivities, with N-ethyl-hexedrone and N-ethyl-pentylone having highest hDAT potencies and N-propyl-pentedrone having highest hDAT selectivity. 4-Cl-ethcathinone and 3,4-methylenedioxy-N-propylcathinone had higher hSERT selectivity. Benzofurans generally had low hDAT selectivity, especially 1-(2,3-dihydrobenzofuran-5-yl)-N-methylpropan-2-amine, with 25-fold higher hSERT potency. Consistent with this selectivity, the benzofurans were releasers at hSERT. Modeling indicated key amino acids in the transporters' binding pockets that influence drug affinities. CONCLUSIONS: The α-pyrrolidinophenones, with high hDAT selectivity, have high abuse potential. Lower hDAT selectivity among benzofurans suggests similarity to methylenedioxymethamphetamine, entactogens with lower stimulant activity.
Assuntos
Alcaloides/metabolismo , Benzofuranos/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Alcaloides/química , Benzofuranos/química , Estimulantes do Sistema Nervoso Central/química , Estimulantes do Sistema Nervoso Central/metabolismo , Estimulantes do Sistema Nervoso Central/farmacologia , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Metilaminas/metabolismo , Norepinefrina/metabolismo , Pentanonas/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Serotonina/metabolismo , Relação Estrutura-Atividade , Proteínas Vesiculares de Transporte de Aminas BiogênicasRESUMO
We report a case of intoxication with a mixture of three synthetic cannabinoids and a synthetic cathinone, which have been disclosed by a highly sensitive progressing technology. A man was found dead, and his forensic autopsy was performed at our department. After further examinations of his specimens, EAM-2201 and α-PVP have been newly found in his lung. The concentrations of EAM-2201 have not been reported yet in any authentic human specimens although its existence (not quantified) in blood was reported in 2015. Therefore, a sensitive quantitation method of these compounds in blood and solid tissues has been devised using the sensitive instrument. The limits of detection of these compounds were in the range of 3-10â¯pg/ml with their quantification range of 10-1000â¯pg/ml in blood. The femoral vein blood levels of EAM-2201 and AB-PINACA were 56.6⯱â¯4.2 and 12.6⯱â¯0.1â¯pg/ml, respectively, and AB-FUBINACA could be detected but not quantifiable in the blood specimens; α-PVP could not be detected. The standard addition method was employed for the quantification of these compounds in the lung, liver and kidney specimens. The lung levels of EAM-2201, AB-PINACA, AB-FUBINACA and α-PVP were 348⯱â¯34, 355⯱â¯30, 124⯱â¯12 and 59.0⯱â¯7.4â¯pg/g, respectively. In conclusion, in this study, the concentrations of EAM-2201 in authentic human specimens including blood and solid tissues and those of AB-PINACA and AB-FUBINACA in solid tissue specimens were quantified for the first time to our knowledge.
Assuntos
Alcaloides/intoxicação , Canabinoides/intoxicação , Indazóis/intoxicação , Indóis/intoxicação , Naftalenos/intoxicação , Pentanonas/intoxicação , Pirrolidinas/intoxicação , Valina/análogos & derivados , Alcaloides/sangue , Alcaloides/metabolismo , Autopsia , Canabinoides/sangue , Canabinoides/metabolismo , Medicina Legal , Humanos , Indazóis/sangue , Indazóis/metabolismo , Indóis/sangue , Indóis/metabolismo , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Masculino , Naftalenos/sangue , Naftalenos/metabolismo , Pentanonas/sangue , Pentanonas/metabolismo , Pirrolidinas/sangue , Pirrolidinas/metabolismo , Distribuição Tecidual , Valina/sangue , Valina/metabolismo , Valina/intoxicaçãoRESUMO
Vicinal diketones produced during wine fermentation influence the organoleptic qualities of wine. Diacetyl and 2,3-pentanedione are well known for their contribution to butter or butterscotch-like flavours. We developed an analysis method to quantify vicinal diketones and their precursors, α-acetolactate and α-acetohydroxybutyrate, under oenological conditions. Five-fold dilution of the sample in a phosphate-citrate buffer (pH7.0) strongly attenuated matrix effects between the beginning and end of alcoholic fermentation and protected the sample from spontaneous precursor decarboxylation. The use of diacetyl-d6 as an internal reference improved precision by eliminating differences in the derivatization and extraction yields between the internal standard and the analytes. We obtained unexpected results for alcoholic fermentation by Saccharomyces cerevisiae using this approach. Indeed, the level of diacetyl and 2,3-pentanedione throughout fermentation were very low. However, we observed a large quantity of both precursors. The production dynamics of α-acetolactate were unconventional and there were two distinct phases of accumulation. The first corresponded to the growth phase, and the second to glucose depletion. There was a rapid decrease of precursor levels at the end of fermentation, but there was still a significant amount of α-acetolactate. The amount of precursor remaining at the end of fermentation constitutes a potential source of diacetyl during wine maturation. α-Acetohydroxybutyrate accumulated during the growth phase followed by a continuous decrease of its concentration during the stationary phase. Residual quantities of α-acetohydroxybutyrate found in wine at the end of fermentation does not constitute a sufficient source of 2,3-pentanedione to affect the aromatic profile.
Assuntos
Fermentação , Microbiologia de Alimentos/métodos , Cetonas/metabolismo , Odorantes/análise , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Vinho/microbiologia , Cromatografia Gasosa-Espectrometria de Massas , Hidroxibutiratos/metabolismo , Lactatos/metabolismo , Pentanonas/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Olfato , Paladar , Fatores de TempoRESUMO
Workplace drug testing in Australia is usually adherent to one of two standards, AS/NZS 4308:2008 for urine or AS 4760:2006 for oral fluid. These standards prescribe the drugs tested, devices used and testing methodology followed by the testing agency. However, they are not comprehensive and for many years workers have been able to consume novel psychoactive substances to avoid detection and without consequences. Here, we present a validated method for the detection of 32 Synthetic Stimulant and Hallucogenic drugs, commonly sold as bath salts, in oral fluid. These drugs are cathinone, ephedrone, methylone, flephedrone, MDA, PMA, methedrone, TMA, MDMA, butylone, mephedrone, MDEA, MEC, pentedrone, MBDB, MTA, Alpha-PVP, MPBP, 2C-B, MDPV, DOB, 2C-T-2, TFMPP, DOET, 2C-T-7, naphyrone, MDAI, FMA, DMA, 25C-NBOMe, 25B-NBOMe and 25T4-NBOMe. Sample preparation was undertaken using a simple protein precipitation in acetonitrile. Chromatographic separation was achieved in 7.5 min on a Kinetex F5 column (50 mm × 3 mm × 2.6 µm) using 0.1% formic acid in water and acetonitrile as the mobile phases. The method was validated with limit of detection (1 ng/mL), limit of quantitation (2.5 ng/mL), selectivity, linearity (2.5-500 ng/mL), accuracy (85.3-108.4% of the target concentration) and precision (1.9-14%). This method was applied to 12 samples previously submitted for routine testing and two were found to contain 2-CB and DOB (5 and 4 ng/mL) and, MPBP and TFMPP (both at 4 ng/mL). This method provides for the rapid detection of a large number of compounds in oral fluid which is readily applicable to routine testing laboratories.
Assuntos
Alcaloides/análise , Drogas Ilícitas/metabolismo , Psicotrópicos/metabolismo , Saliva/metabolismo , Detecção do Abuso de Substâncias/métodos , Anisóis/análise , Austrália , Benzilaminas/análise , Dimetoxifeniletilamina/análogos & derivados , Dimetoxifeniletilamina/metabolismo , Humanos , Drogas Ilícitas/análise , Metanfetamina/análogos & derivados , Metanfetamina/metabolismo , Pentanonas/análise , Pentanonas/metabolismo , Fenetilaminas/análise , Propiofenonas/metabolismo , Pirrolidinas/análise , Pirrolidinas/metabolismoRESUMO
Acyloins are useful organic compounds with reactive adjacent hydroxyl group and carbonyl group. Current research is usually constrained to acetoin (i.e. 3-hydroxy-2-butanone) and the biological production of other acyloins was scarcely reported. In this study, two hydroxy-pentanone metabolites (3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone) of Bacillus sp. H15-1 were identified by gas chromatography-mass spectrometry and authentic standards. Then the complete genome of this strain was sequenced and de novo assembled to a single circular chromosome of 4,162,101bp with a guanine-cytosine content of 46.3%, but no special genes were found for the biosynthesis of the hydroxy-pentanones. Since hydroxy-pentanones are the homologues of acetoin, the two genes alsD and alsS (encoding α-acetolactate decarboxylase and α-acetolactate synthase, respectively) responsible for acetoin formation in this strain were respectively expressed in Escherichia coli. The purified enzymes were found to be capable of transforming pyruvate and 2-oxobutanoate to the two hydroxy-pentanones. This study extends the knowledge on the biosynthesis of acyloins and provides helpful information for further utilizing Bacillus sp. H15-1 as a source of valuable acyloins.
Assuntos
Bacillus/genética , Escherichia coli/genética , Genoma Bacteriano/genética , Pentanonas/metabolismo , Acetoína/metabolismo , Bacillus/enzimologia , Escherichia coli/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Engenharia Metabólica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
A stable isotope dilution assay was developed for quantitation of 4-methyl-4-sulfanylpentan-2-one (4MSP) in hops. The approach included the use of 4-(13C)methyl-4-sulfanyl(1,3,5-13C3)pentan-2-one as internal standard, selective isolation of hop thiols by mercurated agarose, and GC×GC-TOFMS analysis. Application of the method to 53 different hop samples revealed 4MSP concentrations between <1 and 114 µg/kg. Notably high concentrations were associated with United States varieties such as Citra, Eureka, Simcoe, and Apollo, whereas 4MSP was absent from traditional German and English varieties. Further experiments showed that besides the variety, also harvest year and storage vitally influenced 4MSP concentrations, whereas the impact of provenance was less pronounced. Hop processing such as drying and pelletizing had only a minor impact on 4MSP concentrations. Like the majority of other hop volatiles, 4MSP is predominantly located in the lupulin glands.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Humulus/química , Técnicas de Diluição do Indicador , Pentanonas/química , Extratos Vegetais/química , Compostos de Sulfidrila/química , Humulus/classificação , Humulus/crescimento & desenvolvimento , Humulus/metabolismo , Pentanonas/metabolismo , Extratos Vegetais/metabolismo , Compostos de Sulfidrila/metabolismoRESUMO
The toxic effects of diethylketone (DEK) in aqueous solution with different concentrations of Al3+, Cd2+, Ni2+ and Mn2+ were evaluated at lab-scale. It was established that Streptococcus equisimilis is able to efficiently remove DEK with different concentrations with heavy metals. It was proved that this joint-system has excellent capacity to biodegrade high concentrations of DEK in the presence of Al3+, Cd2+, Ni2+ and Mn2+. With the exception of Al3+, the uptake for all metals increased as the initial concentration of each metal in the mixed solution increased. The breakthrough curves are best described by the Adams and Bohart model for Cd2+, by the Yoon and Nelson model for Ni2+ and by the Wolborska model for Mn2+.
Assuntos
Silicatos de Alumínio/química , Poluentes Ambientais/metabolismo , Pentanonas/metabolismo , Streptococcus/metabolismo , Eliminação de Resíduos Líquidos/métodos , Adsorção , Alumínio/química , Alumínio/metabolismo , Biodegradação Ambiental , Argila , Poluentes Ambientais/química , Metais Pesados/química , Metais Pesados/metabolismo , Pentanonas/química , Projetos Piloto , Eliminação de Resíduos Líquidos/instrumentaçãoRESUMO
BACKGROUND: The present paper details a new technique based on spraying nebulized water on vine canopy to counteract the negative impact of the current wave of hot summers with temperatures above 30 °C, which usually determine negative effects on vine yield, grape composition and wine quality. RESULTS: The automatized spraying system was able to maintain air temperature at below 30 °C (the threshold temperature to start spraying) for all of August 2013, when in the canopy of uncooled vines the temperature was as high as 36 °C. The maintenance of temperature below 30 °C reduced leaf stress linked to high temperature and irradiance regimes as highlighted by the decrease of H2 O2 content and catalase activity in the leaves. A higher amount of total polyphenols and organic acids and lower sugars characterized the grapes of cooled vines. Wine from these grapes had a higher content of some volatile thiols like 3-sulfanylhexanol (3SH) and 3-sulfanylhexylacetate (3SHA), and lower content of 4-methyl-4-sulfanylpentan-2-one (4MSP). CONCLUSION: Under conditions of high temperature and irradiance regimes, water nebulization on the vine canopy can represent a valid solution to reduce and/or avoid oxidative stress and associated effects in the leaves, ensure a regular berry ripening and maintain high wine quality. The consumption of water during nebulization was acceptable, being 180 L ha-1 min-1 , which lasted an average of about 1 min to reduce the temperature below the threshold value of 30 °C. A total of 85-90 hL (from 0.8 to 0.9 mm) of water per hectare per day was required. © 2016 Society of Chemical Industry.
Assuntos
Agricultura/métodos , Frutas/metabolismo , Folhas de Planta , Temperatura , Vitis/metabolismo , Água , Vinho/análise , Ácidos/metabolismo , Aerossóis , Metabolismo dos Carboidratos , Catalase/metabolismo , Aquecimento Global , Humanos , Peróxido de Hidrogênio/metabolismo , Luz , Estresse Oxidativo , Pentanonas/metabolismo , Polifenóis/metabolismo , Estações do Ano , Compostos de Sulfidrila/metabolismo , Vinho/normasRESUMO
BACKGROUND: Regulated deficit irrigation (RDI) is used in hedgerow olive orchards to achieve a sustainable balance between water savings, tree vigor and oil production. Its effects on the presence of compounds responsible for the taste of the oil and its nutritional value are controversial. The present 3-year study was conducted in an 'Arbequina' orchard (1667 trees ha-1 ) under a full irrigation (FI) treatment (470.1 mm year-1 of water) and two RDI treatments scaled to replace 60% and 30%, respectively, of FI. The quality parameters, antioxidant contents and volatiles of the extracted virgin olive oil (VOO) were analyzed. RESULTS: In general, oils from the 30% RDI treatment had higher contents of pigments and phenolic compounds, a higher oleic/linoleic ratio and the highest oxidative stability, despite their lower tocopherol content. FI oils showed higher (E)-2-hexenal, 1-penten-3-one, ocimene, E-2-pentenal and pentene dimer contents than 30RDI oils, but lower contents of (E)-2-pentenol and volatile esters. CONCLUSION: The results of the present study suggest that a RDI strategy supplying 30% of the total irrigation needs induces an increase in natural antioxidants in VOO. Neither yield, nor the rest of the quality parameters were affected by the reduced irrigation. However, abundant autumn precipitation can over-ride these effects of 30% RDI treatment on oil quality. © 2016 Society of Chemical Industry.
Assuntos
Irrigação Agrícola/métodos , Qualidade dos Alimentos , Frutas/química , Frutas/crescimento & desenvolvimento , Olea/química , Olea/crescimento & desenvolvimento , Azeite de Oliva/análise , Aldeídos/análise , Aldeídos/metabolismo , Antioxidantes/análise , Antioxidantes/metabolismo , Conservação dos Recursos Naturais , Produção Agrícola , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , União Europeia , Frutas/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Valor Nutritivo , Olea/metabolismo , Azeite de Oliva/normas , Oxirredução , Pentanonas/análise , Pentanonas/metabolismo , Pigmentos Biológicos/análise , Pigmentos Biológicos/biossíntese , Espanha , Tocoferóis/análise , Tocoferóis/metabolismo , Regulação para Cima , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismoRESUMO
The purpose of this work was to study the potential of gas chromatography-ion mobility spectrometry (GC-IMS) to differentiate lactic acid bacteria (LAB) through target identification and fingerprints of volatile metabolites. The LAB selected were used as reference strains for their influence in the flavour of cheese. The four strains of LAB can be distinguished by the fingerprints generated by the volatile organic compounds (VOCs) emitted. 2-butanone, 2-pentanone, 2-heptanone and 3-methyl-1-butanol were identified as relevant VOCs for Lactobacillus casei and Lactobacillus paracasei subsp. paracasei. 2-Butanone and 3-methyl-1-butanol were identified in Lactococcus lactis subsp. lactis and Lactococcus cremoris subsp. cremoris. The IMS signals monitoring during a 24-30h period showed the growth of the LAB in vitro. The results demonstrated that GC-IMS is a useful technology for bacteria recognition and also for screening the aromatic potential of new isolates of LAB.
Assuntos
Queijo/microbiologia , Cromatografia Gasosa/métodos , Ácido Láctico/metabolismo , Lacticaseibacillus casei/isolamento & purificação , Lactococcus lactis/isolamento & purificação , Análise Espectral/métodos , Butanonas/metabolismo , Microbiologia de Alimentos , Cetonas/metabolismo , Lacticaseibacillus casei/metabolismo , Lactococcus lactis/metabolismo , Pentanóis/metabolismo , Pentanonas/metabolismoRESUMO
The grassy characteristic aroma perceived in brewed sake made from low-glutelin rice (Oryza sativa L. Mizuhonoka) was examined by gas chromatography-olfactometry and gas chromatography-mass spectrometry. By comparing the odor properties and Kovats retention indices to those of standard compounds, 4-mercapto-4-methylpentan-2-one (4MMP) was found to contribute to the characteristic aroma. Sake brewing using Mizuhonoka, low-glutelin rice, and Gin-ohmi (a control) revealed that 4MMP concentrations in Mizuhonoka sake samples were higher than those in Gin-ohmi samples over the fermentation period. The concentration in final Mizuhonoka sake was twice that of Gin-ohmi. To investigate the mechanism of 4MMP formation, the putative precursors, 4-S-cycteinyl-4-methylpentan-2-one (cys-4MMP) and 4-S-glutathionyl-4-methylpentan-2-one (glut-4MMP), in sake and its materials (rice and koji) were analyzed by ultra-performance liquid chromatography tandem mass-spectrometry. Cys-4MMP was not detected in all samples, while glut-4MMP was present in sake and its materials. The glut-4MMP concentration in sake was lower than that in Gin-ohmi over nearly the entire fermentation period, suggesting that conversion of the precursors to 4MMP was more effective in the mash of low-glutelin rice Mizuhonoka than in Gin-ohmi. The release of 4MMP during alcoholic fermentation from a model medium containing its precursors was examined. While no 4MMP release was observed in the control (no addition), with the addition of its precursors, the release of 4MMP increased as fermentation progressed. It was suggested that 4MMP was generated from both cys- and glut-4MMP by sake yeast. The perception threshold of 4MMP in sake was determined as 1.2 ng/L.