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1.
Food Chem ; 314: 126183, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31972407

RESUMO

Phenolic compounds largely contribute to the nutraceutical properties of virgin olive oil (VOO), the organoleptic attributes and the shelf life due to their antioxidant capabilities. Due to the relevance of malaxation in the oil extraction process, we tested the effects of malaxation time on the concentrations of relevant phenolic compounds in VOO, and we evaluated the influence of performing malaxation under vacuum. An increase in malaxation time significantly decreased the concentrations of aglycone isomers of oleuropein and ligstroside but, conversely, increased the oleocanthal and oleacein contents. Additionally, malaxation under vacuum led to an increase in phenolic contents compared to standard conditions carried out at atmospheric pressure. Finally, we explored the possibility of predicting the VOO oxidative stability on the basis of the phenolic profile, and a model (R2 = 0.923; p < 0.0001) was obtained by combining the concentration of the VOO phenolic compounds and the main fatty acids.


Assuntos
Manipulação de Alimentos/métodos , Azeite de Oliva/química , Fenóis/análise , Fenóis/química , Aldeídos/análise , Aldeídos/química , Monoterpenos Ciclopentânicos/análise , Monoterpenos Ciclopentânicos/química , Ácidos Graxos/análise , Ácidos Graxos/química , Glucosídeos/análise , Glucosídeos/química , Iridoides/análise , Iridoides/química , Azeite de Oliva/análise , Oxirredução , Piranos/análise , Piranos/química , Temperatura , Fatores de Tempo
2.
Molecules ; 25(1)2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31877660

RESUMO

Methanol is metabolized in the body to highly toxic formaldehyde and formate when consumed accidentally. Methanol has been typically analyzed with gas chromatography-flame ionization detector (GC-FID). However, its retention time may overlap with other volatile compounds and lead to confusion. Alternative analysis of methanol using gas chromatography/mass spectrometry (GC/MS) also has limitations due to its similar molecular weight with oxygen and low boiling point. In this study, methanol and internal standard of deuterium-substituted ethanol were derivatized with 3,4-dihydro-2H-pyran under acid catalysis using concentrated hydrochloric acid. The reaction products including 2-methoxytetrahydropyran were extracted with solid-phase microextraction followed by GC/MS analysis. This method was successfully applied to measure the lethal concentration of methanol in the blood of a victim with a standard addition method to overcome the complex matrix effect of the biospecimen. Identification of the metabolite formate by ion chromatography confirmed the death cause to be methanol poisoning. This new method was a much more convenient and reliable process to measure methanol in complex matrix samples by reducing sample pretreatment effort and cost.


Assuntos
Benzenossulfonatos/análise , Metanol/química , Piranos/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Metanol/envenenamento
3.
Talanta ; 205: 120107, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450415

RESUMO

A comprehensive structural characterization of the complex family of isomeric forms related to Oleuropein aglycone (OA) detected in virgin olive oil (VOO) was performed by reverse phase liquid chromatography with electrospray ionization and Fourier-transform mass spectrometry (RPLC-ESI-FTMS), integrated by enzymatic/chemical reactions performed on Oleuropein, the natural precursor of OA. First, some of the OA-related isomers typically observed in VOO extracts were generated upon enzymatic hydrolysis of the glycosidic linkage of Oleuropein. This step mimicked the process occurring during olive drupes crushing in the first stage of oil production. The incubation of the enzymatic reaction mixture at a more acidic pH was subsequently performed, to simulate the conditions of olive paste malaxation during oil production. As a result, further isomeric forms were generated and the complex chromatographic profile typically observed for OA in olive oil extracts, including at least 13 different peaks/bands/groups of peaks, was carefully reproduced. Each of those chromatographic features could be subsequently assigned to specific types of OA-related isomers, belonging to one of four structurally different classes. Specifically, diastereoisomers/geometrical isomers corresponding to two different types of open-structure forms and to as many types of closed-structure, di-hydropyranic forms of OA, characterized by the presence of one or two carbonyl groups, according to the case, were evidenced. In addition, the presence of stable enolic/dienolic tautomers, providing an indirect structural confirmation for some OA isomers, was ascertained through RPLC-ESI-FTMS analyses performed under H/D exchange conditions, i.e. in the presence of deuterated water as one of the mobile phase solvents.


Assuntos
Acetatos/análise , Monoterpenos Ciclopentânicos/análise , Azeite de Oliva/análise , Piranos/análise , Acetatos/química , Acetatos/isolamento & purificação , Cromatografia de Fase Reversa/métodos , Monoterpenos Ciclopentânicos/química , Monoterpenos Ciclopentânicos/isolamento & purificação , Deutério , Análise de Fourier , Hidrólise , Iridoides/química , Isomerismo , Extração Líquido-Líquido , Olea/química , Piranos/química , Piranos/isolamento & purificação , Espectrometria de Massas em Tandem/métodos , beta-Glucosidase/química
4.
Food Chem ; 300: 125243, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357015

RESUMO

Fatty acids, phenolic compounds, and tocopherols of Coratina, Bosana, Semidana, and Tonda di Cagliari virgin olive oils, were measured over a 45-day harvest period. Phenolic composition was the primary factor distinguishing Bosana, Tonda di Cagliari, and Semidana, whereas fatty acids differentiated Coratina and the other cultivars. Harvest period principally influenced oleacein, oleocanthal, oleuropein and ligstroside aglycones, and flavonoids. High phenolic content was observed for Coratina (1039-688 mg/kg) and Bosana (788-592 mg/kg). A drastic decrease in phenolic content was observed in Semidana (529-134 mg/kg) and Tonda di Cagliari (507-142 mg/kg) during the harvest period. These two cultivars also had low MUFA/PUFA (6.0-4.0 and 4.9-3.2 respectively), suggesting that these varieties should be harvested earlier in the season. These results provide information to producers for improved management of the harvesting process, which is strongly affected by varietal factors.


Assuntos
Análise de Alimentos/métodos , Azeite de Oliva/análise , Azeite de Oliva/química , Agricultura , Aldeídos/análise , Monoterpenos Ciclopentânicos , Ácidos Graxos/análise , Flavonoides/análise , Análise de Alimentos/estatística & dados numéricos , Glucosídeos/análise , Iridoides/análise , Itália , Olea/química , Fenóis/análise , Piranos/análise , Especificidade da Espécie , Tocoferóis/análise
5.
Food Chem ; 298: 125011, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31261011

RESUMO

A scallop midgut gland certified reference material, NMIJ CRM 7520-a, was developed for validation and quality assurance during the inspection of shellfish for diarrhetic shellfish toxins. The candidate material was prepared by using naturally-toxic and nontoxic boiled midgut glands spiked with okadaic acid (OA). The homogeneity and stability of the material were found to be appropriate. For the characterization of OA and dinophysistoxin-1 (DTX1), nine participants were involved in a co-laboratory study based on the Japanese Official Testing Method, where the compounds were assayed by liquid chromatography-tandem mass spectrometry following alkaline hydrolysis. The analytical values were obtained by the standard addition method with a standard spiking solution calibrated using the standard-solution certified reference materials OA and DTX1. The certified concentrations with expanded uncertainties (coverage factor k = 2, approximate 95% confidence interval) were determined to be (0.205 ±â€¯0.061) mg/kg for OA and (0.45 ±â€¯0.11) mg/kg for DTX1.


Assuntos
Diarreia/complicações , Toxinas Marinhas/análise , Pectinidae/química , Piranos/análise , Frutos do Mar/análise , Animais , Calibragem , Cromatografia Líquida , Humanos , Intestinos/química , Toxinas Marinhas/normas , Toxinas Marinhas/toxicidade , Ácido Okadáico/análise , Piranos/normas , Piranos/toxicidade , Padrões de Referência , Intoxicação por Frutos do Mar/complicações , Espectrometria de Massas em Tandem
6.
BMC Complement Altern Med ; 19(1): 130, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31200712

RESUMO

BACKGROUND: Angoroside C, cinnamic acid, and harpagoside are bioactive constituents in Scrophularia ningpoensis. Currently, an infrared-assisted extraction (IRAE) method coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) for the analysis of bioactive constituents in this plant is lacking. METHODS: A method based on HPLC following IRAE has been developed for quantifying angoroside C, cinnamic acid, and harpagoside in Scrophularia ningpoensis. Four main factors, namely, extraction solvent, solid/liquid ratio, illumination time, and distance between the infrared lamp and the round-bottom flask, were optimized for extraction. Furthermore, conventional ultrasonic extraction (USE) and microwave-assisted extraction (MAE) were also investigated to validate the developed method. RESULTS: The optimal extraction conditions were as follows: ethanol concentration, 37.5%; solid/liquid ratio, 1:25; illumination time, 10 min; and distance between infrared lamp and round-bottom flask, 3 cm. The results of method validation demonstrated that the developed method meets the requirement of analysis. CONCLUSION: The results show that the IRAE-HPLC is a simple, accurate, and green analytical preparatory method for the potential extraction and quantification of angoroside C, cinnamic acid, and harpagoside in Scrophularia ningpoensis.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cinamatos/análise , Ácidos Cumáricos/análise , Glicosídeos/análise , Piranos/análise , Scrophularia/química , Trissacarídeos/análise
7.
Colloids Surf B Biointerfaces ; 180: 298-305, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31071569

RESUMO

Formulation of new liposoma-based systems can always be in the spotlight for their unique utilization as carriers. Some changes in the composition of lipids may give rise to new mixed liposomes exhibiting modified size and physico-chemical characteristics. Consequently, these display different encapsulating properties toward various molecules. In this work, we have explored the variations in the model lecithin liposomes with casein additive from their size, shape, microenvironment and dynamics in solution. It is observed that with introduction of casein, the size of the liposome is substantially reduced due to incorporation of the additive in its bilayer. Strong interaction between the hydrophobic side chains of casein and lipid bilayer, and electrostatic repulsion of head groups of lipid are responsible to result small casein-mixed liposomes. Spectral properties of coumarin-153 disclose that the microenvironment of the bi-layer of mixed system is predominantly hydrophobic in nature and much rigid too. Fluorescence-lifetime-imaging-microscopy indicates that casein mixed systems exhibit wider lifetime distribution than pure liposomes with predominance of longer lifetimes, entirely arising from the outer bilayer. This indicates that casein gets incorporated in the bilayer of the vesicle to cater rigid and more hydrophobic microenvironment with an effective decrease in size. It is found that such mixed system is very efficient to stabilize the hydrophobic drugs (curcumin and ß-carotene) for prolonged period than the pure liposome or casein-only. The findings are indeed important from the perspective of drug stabilization by liposomes, and is suggestive of possible utilization in oral drug delivery applications involving such size-reduced nano-encapsulates.


Assuntos
Caseínas/química , Interações Hidrofóbicas e Hidrofílicas , Lecitinas/química , Lipossomos/química , Substâncias Macromoleculares/química , Tamanho da Partícula , Piranos/análise , Espectrometria de Fluorescência , Estirenos/análise
8.
Environ Pollut ; 249: 171-180, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30884396

RESUMO

Lipophilic marine toxins in shellfish pose significant threats to the health of seafood consumers. To assess the contamination status of shellfish by lipophilic marine toxins in the Bohai Sea, nine species of shellfish periodically collected from five representative aquaculture zones throughout a year were analyzed with a method of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lipophilic marine toxins, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), yessotoxin (YTX), homo-yessotoxin (homo-YTX), azaspiracids (AZA2 and AZA3), gymnodimine (GYM), and 13-desmethyl spirolide C (13-DesMe-C), were detected in more than 95 percent of the shellfish samples. Toxins PTX2, YTX, 13-DesMe-C and GYM were predominant components detected in shellfish samples. Scallops, clams and mussels accumulated much higher level of lipophilic marine toxins compared to oysters. Toxin content in shellfish samples collected from different sampling locations showed site-specific seasonal variation patterns. High level of toxins was found during the stages from December to February and June to July in Hangu, while from March to April and August to September in Laishan. Some toxic algae, including Dinophysis acuminata, D. fortii, Prorocentrum lima, Gonyaulax spinifera and Lingulodinium polyedrum, were identified as potential origins of lipophilic marine toxins in the Bohai Sea. The results will offer a sound basis for monitoring marine toxins and protecting the health of seafood consumers.


Assuntos
Toxinas Marinhas/análise , Frutos do Mar/análise , Poluentes Químicos da Água/análise , Animais , Bivalves/química , China , Cromatografia Líquida/métodos , Dinoflagelados , Furanos/análise , Compostos Heterocíclicos com 3 Anéis/análise , Hidrocarbonetos Cíclicos/análise , Iminas/análise , Ácido Okadáico/análise , Ostreidae/química , Oxocinas/análise , Piranos/análise , Alimentos Marinhos/análise , Frutos do Mar/estatística & dados numéricos , Compostos de Espiro/análise , Espectrometria de Massas em Tandem
9.
Food Res Int ; 116: 447-454, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30716967

RESUMO

'Brava' and 'Mansa de Figueiredo' extra-virgin olive oils (EVOOs) are two varieties identified from north-western Spain. A systematic phenolic characterization of the studied oils was undertaken by LC-ESI-IT-MS. In addition, the role of dietary polyphenols from these EVOOs has been evaluated against the inhibition of key enzymes (α-glucosidase and α-amylase) in the management of diabetes mellitus (DM). Oleuropein and ligstroside derivatives comprised 83% and 67% of the total phenolic compounds in 'Brava' and 'Mansa de Figueiredo' EVOOs, respectively. The main secoiridoids from oleuropein were DOA (3,4-DHPEA-EDA, 59 and 22 mg kg-1, respectively) and the main isomer of OlAgl (3,4-DHPEA-EA, 74 and 23 mg kg-1). The main secoiridoids from ligstroside were D-LigAgl (p-HPEA-EDA or oleocanthal, 23 and 167 mg kg-1) and the main isomer of LigAgl (p-HPEA-EA, 214 and 114 mg kg-1). For α-glucosidase, both EVOO extracts displayed stronger inhibitory activity (IC50 values of 60 ±â€¯8 and 118 ±â€¯9 µg mL-1, respectively) than the commercial inhibitor acarbose (IC50 = 356 ±â€¯21 µg mL-1). Nevertheless, for α-amylase, only 'Brava' extracts showed anti-α-amylase capacity. A daily VOO intake lower than the requirements of EFSA seem to be enough to reach both 50% for α-glucosidase and 25% for α-amylase inhibition. These findings support the potential health benefits derived from Galician EVOOs that might be probably linked to the outstanding high concentration levels of phenolic acids and flavonoids.


Assuntos
Azeite de Oliva/química , Extratos Vegetais/análise , Extratos Vegetais/farmacologia , alfa-Amilases/efeitos dos fármacos , alfa-Glucosidases/efeitos dos fármacos , Aldeídos/análise , Monoterpenos Ciclopentânicos/análise , Diabetes Mellitus Tipo 2 , Flavonoides , Glucosídeos/análise , Inibidores de Glicosídeo Hidrolases/farmacologia , Hipoglicemiantes/farmacologia , Iridoides/análise , Fenóis/análise , Fenóis/farmacologia , Piranos/análise , Espanha
10.
Toxins (Basel) ; 11(2)2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30717091

RESUMO

Blooms of the dinoflagellate Dinophysis acuminata occur every year in an important mussel cultivation area in Port Underwood, Marlborough Sounds, New Zealand. Annual maximum cell numbers range from 1500⁻75,000 cells L-1 and over 25 years of weekly monitoring the D. acuminata bloom has never failed to exhibit peaks in abundance at some time between spring and autumn. During winter (June⁻August) the dinoflagellate is often undetectable, or at low levels (≤100 cells L-1), and the risk of diarrhetic shellfish poisoning (DSP)-toxin contamination over this period is negligible. Bloom occurrence may be coupled to the abundance of D. acuminata prey (Mesodinium sp.) but the mechanism by which it maintains its long-term residence in this hydrologically dynamic environment is unknown. The toxin profile of D. acuminata is dominated by pectenotoxin-2 (PTX-2) and dinophysistoxin-1 (DTX-1), but the cellular toxin content is low. It is rare that free DTX-1 is detected in mussels as this is invariably exclusively present as fatty acid-esters. In only five out of >2500 mussel samples over 16 years have the levels of total DTX-1 marginally exceeded the regulated level of 0.16 mg kg-1. It is also rare that free PTX-2 is detected in mussels, as it is generally only present in its hydrolysed non-toxic PTX-2 seco acid form. The D. acuminata alert level of 1000 cells L-1 is often exceeded without DTX-1 residues increasing appreciably, and this level is considered too conservative.


Assuntos
Dinoflagelados , Furanos/análise , Toxinas Marinhas/análise , Perna (Organismo) , Piranos/análise , Poluentes da Água/análise , Animais , Monitoramento Ambiental , Proliferação Nociva de Algas , Nova Zelândia , Frutos do Mar/análise , Intoxicação por Frutos do Mar
11.
Chem Res Toxicol ; 32(2): 304-311, 2019 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-30640474

RESUMO

Glucose degradation products (GDPs) are formed from glucose and other reducing sugars during heat treatment, for example, in heat-sterilized peritoneal dialysis fluids or foods. Because of their reactive mono- and dicarbonyl structure, they react readily with proteins, resulting in the formation of advanced glycation end products (AGEs), loss of protein functionality, and cytotoxicity. Among the GDPs, 3,4-dideoxyglucosone-3-ene (3,4-DGE) exerts the strongest effects despite its relatively low concentration levels. The goal of the present study was therefore to identify the structure of specific protein modifications deriving from 3,4-DGE. A nonapeptide containing the reactive amino acids lysine, arginine, and cysteine was incubated with 3,4-DGE and the dominant GDPs 3-deoxyglucosone (3-DG) and 3-deoxygalactosone (3-DGal) in concentrations as present in peritoneal dialysis fluids (235 µM 3-DG, 100 µM 3-Gal, and 11 µM 3,4-DGE). Glycation rate and product formation were determined by ultra-HPLC-MS/MS (UHPLC-MS/MS). 3,4-DGE showed the strongest glycation activity. After 2 h of incubation, 3,4-DGE had modified 57% of the nonapeptide, whereas 3-DG had modified only 2% and 3-DGal had modified 29% of the peptide. A stable 3,4-DGE-derived cysteine modification was isolated. Its structure was determined by comprehensive NMR and MS experiments to be [6-hydroxy-2-(hydroxymethyl)-5-oxo-5,6-dihydro-2 H-pyran-3-yl]-cysteine (HHPC), which represents a novel cysteine-AGE derived from 3,4-DGE. The results indicate that 3,4-DGE might contribute to a severe loss of protein functionality by forming cysteine-specific AGEs, such as HHPC.


Assuntos
Cisteína/química , Cistina/análise , Soluções para Diálise/química , Piranos/análise , Pironas/química , Cromatografia Líquida de Alta Pressão , Cistina/química , Desoxiglucose/análogos & derivados , Desoxiglucose/análise , Galactose/análogos & derivados , Galactose/análise , Produtos Finais de Glicação Avançada/análise , Peptídeos/química , Piranos/química , Espectrometria de Massas em Tandem
12.
J Asian Nat Prod Res ; 21(10): 939-946, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29966449

RESUMO

Two new 2H-pyranones and two new isocoumarin derivatives, maculanslines A-D (1-4), together with seven known compounds (5-11), were isolated from the plant pathogenic fungus Leptosphaena maculans. Their planar structures and absolute configuration were elucidated by comprehensive spectroscopic techniques including high-resolution electrospray ionization mass spectrum, 1D and 2D nuclear magnetic resonance, as well as electronic circular dichroism. All 11 compounds were tested for their inhibitory activity against α-glucosidase. Compound 1 showed moderate inhibitory activity against α-glucosidase with IC50 of 74.35 µM.


Assuntos
Fungos/química , Isocumarinas/análise , Piranos/análise , Dicroísmo Circular , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Isocumarinas/isolamento & purificação , Isocumarinas/farmacologia , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Doenças das Plantas , Piranos/farmacologia , Espectrometria de Massas por Ionização por Electrospray
13.
Nat Prod Res ; 33(21): 3171-3175, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30303396

RESUMO

Olive mill wastewaters (OMWs) are important by-products of olive oil production. The wide availability and the forbidding economic costs of OMWs disposal have generated interest in their possible exploitation as a sustainable source of polyphenols. The development and optimisation of improved analytical methods for the detailed characterisation of polyphenol molecular profiles after production and during storage conditions are thus required. A new analytical method based on reverse-phase HPLC separation of polyphenols in OMWs on an embedded-polar group (EPG) stationary phase is proposed as an alternative to conventional C18 columns. The procedure was used for the quantitation of 11 polyphenols, using diode-array detection (DAD), and achieving quantitation limits equal to or lower than 0.1 µg g-1. The same chromatographic set-up, coupled with high resolution tandem mass spectrometry (HPLC/ESI-Q-ToF), allowed us to identify hydroxytyrosyl esters of elenolic acid, whose relative abundance is proposed for monitoring the ageing of OMWs during storage.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Azeite de Oliva , Fenóis/análise , Piranos/análise , Águas Residuárias/análise , Cromatografia Líquida de Alta Pressão/instrumentação , Indústria de Processamento de Alimentos , Polifenóis/análise , Espectrometria de Massas em Tandem/métodos , Águas Residuárias/química
14.
Phytochemistry ; 158: 149-155, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30576968

RESUMO

From two species of Sutera (S. foetida and S. cordata) (Scrophulariaceae tribe Limoselleae) were isolated three known secoiridoid glucosides (12-14) as well as four iridoid congeners (8-11), all biosynthetically derived from iridodial glucoside (and/or deoxyloganic acid). In addition, two previously unknown compounds were found, namely a terpenoid glucoside lactone (suterolide, 21) and the phenylethanoid glycoside 2''''-O-acetyl-angoroside A (19) as well as verbascoside, echinacoside and tubuloside A(15-17, respectively). Two other species, Jamesbrittenia dissecta and Lyperia antirrhinoides, previously considered to belong to the same genus (Sutera) were shown to be members of two different genera, respectively. Significantly, these two species contained iridoids derived from 8-epi-iridodial (and 8-epideoxyloganic acid), namely aucubin (2), melittoside (3) and acetylharpagide (4). In addition we investigated Melanospermum transvaalense, Lyperia tristis and Microdon dubius likewise from Limoselleae and all of these contained iridoid glucosides from the 8-epi-pathway. Thus, secoiridoid distribution confirms the DNA-based circumscription of Sutera and its sister-group relationship with Manulea. In addition, the results show that the clade including these two genera has a biosynthetic pathway to iridoids fundamentally different from the rest of the tribe and from the whole family Scrophulariaceae.


Assuntos
Glucosídeos Iridoides/química , Scrophulariaceae/química , Scrophulariaceae/classificação , Glucosídeos/análise , Glucosídeos/química , Glicosídeos/análise , Glicosídeos/química , Glucosídeos Iridoides/análise , Glucosídeos Iridoides/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Fenóis/análise , Fenóis/química , Filogenia , Piranos/análise , Piranos/química , Scrophulariaceae/genética , Espectrometria de Massas por Ionização por Electrospray
15.
Molecules ; 23(12)2018 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-30567348

RESUMO

Three phenylethanoid glycosides, echinacoside (1), salidroside (3), and acteoside (6), and three secoiridoid glycosides, isonuezhenide (2), nuezhenoside G13 (4), and specnuezhenide (5), have been extracted and separated by a combined method of ultrahigh pressure extraction (UPE) and high-speed counter-current chromatography (HSCCC) from Ligustri Lucidi Fructus. For the UPE, the optimal extraction was developed with conditions including solvent of 90% ethanol, sample to solvent ratio of 1:20 g/mL, pressure of 200 MPa, and time of 2 min, which rendered the yields of compounds 4 and 5 were 15.0 and 78.0 mg/g, respectively. For the HSCCC separation, the strategy of changing flow rates between 1.0 and 2.0 mL/min allowed the acquisition for 2.7 mg of compound 1, 4.5 mg of compound 2, 6.8 mg of compound 3, 5.9 mg of compound 4, 11.2 mg of compound 5, and 2.2 mg of compound 6 in one separation run under the solvent system of ethyl acetate:n-butanol:water (2:1:3, v/v) from 200 mg of the UPE extract. The structures of these phenylethanoid and secoiridoid glycosides were elucidated by extensive spectroscopic methods.


Assuntos
Glicosídeos/análise , Cromatografia Líquida de Alta Pressão , Distribuição Contracorrente , Glucosídeos/análise , Glicosídeos Iridoides/análise , Ligustrum/química , Fenóis/análise , Extratos Vegetais/análise , Piranos/análise
16.
Food Chem ; 266: 192-199, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30381176

RESUMO

Despite the evident influence of the cultivar on olive oil composition, few studies have been devoted to exploring the variability of phenols in a representative number of monovarietal olive oils. In this study, oil samples from 80 cultivars selected for their impact on worldwide oil production were analyzed to compare their phenolic composition by using a method based on LC-MS/MS. Secoiridoid derivatives were the most concentrated phenols in virgin olive oil, showing high variability that was significantly due to the cultivar. Multivariate analysis allowed discrimination between four groups of cultivars through their phenolic profiles: (i) richer in aglycon isomers of oleuropein and ligstroside; (ii) richer in oleocanthal and oleacein; (iii) richer in flavonoids; and (iv) oils with balanced but reduced phenolic concentrations. Additionally, correlation analysis showed no linkage among aglycon isomers and oleocanthal/oleacein, which can be explained by the enzymatic pathways involved in the metabolism of both oleuropein and ligstroside.


Assuntos
Variação Biológica da População , Olea/química , Azeite de Oliva/análise , Fenóis/análise , Compostos Fitoquímicos/análise , Aldeídos/análise , Cromatografia Líquida , Monoterpenos Ciclopentânicos , Flavonoides/análise , Glucosídeos/análise , Iridoides/análise , Análise Multivariada , Piranos/análise , Espectrometria de Massas em Tandem
17.
Toxins (Basel) ; 10(12)2018 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-30477142

RESUMO

Causative species of Harmful Algal Bloom (HAB) and toxins in commercially exploited molluscan shellfish species are monitored weekly from four classified shellfish production areas in Perú (three in the north and one in the south). Okadaic acid (OA) and pectenotoxins (PTXs) were detected in hand-picked cells of Dinophysis (D. acuminata-complex and D. caudata) and in scallops (Argopecten purpuratus), the most important commercial bivalve species in Perú. LC-MS analyses revealed two different toxin profiles associated with species of the D. acuminata-complex: (a) one with OA (0.3⁻8.0 pg cell-1) and PTX2 (1.5⁻11.1 pg cell-1) and (b) another with only PTX2 which included populations with different toxin cell quota (9.3⁻9.6 pg cell-1 and 5.8⁻9.2 pg cell-1). Toxin results suggest the likely presence of two morphotypes of the D. acuminata-complex in the north, and only one of them in the south. Likewise, shellfish toxin analyses revealed the presence of PTX2 in all samples (10.3⁻34.8 µg kg-1), but OA (7.7⁻15.2 µg kg-1) only in the northern samples. Toxin levels were below the regulatory limits established for diarrhetic shellfish poisoning (DSP) and PTXs (160 µg OA kg-1) in Perú, in all samples analyzed. This is the first report confirming the presence of OA and PTX in Dinophysis cells and in shellfish from Peruvian coastal waters.


Assuntos
Dinoflagelados/citologia , Furanos/análise , Toxinas Marinhas/análise , Ácido Okadáico/análise , Pectinidae/química , Piranos/análise , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Peru
18.
Toxins (Basel) ; 10(10)2018 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-30274219

RESUMO

Diarrhetic shellfish toxins produced by the dinoflagellate genus Dinophysis are a major problem for the shellfish industry worldwide. Separate species of the genus have been associated with the production of different analogues of the okadaic acid group of toxins. To evaluate the spatial and temporal variability of Dinophysis species and toxins in the important shellfish-harvesting region of the Scottish west coast, we analysed data collected from 1996 to 2017 in two contrasting locations: Loch Ewe and the Clyde Sea. Seasonal studies were also undertaken, in Loch Ewe in both 2001 and 2002, and in the Clyde in 2015. Dinophysis acuminata was present throughout the growing season during every year of the study, with blooms typically occurring between May and September at both locations. The appearance of D. acuta was interannually sporadic and, when present, was most abundant in the late summer and autumn. The Clyde field study in 2015 indicated the importance of a temperature front in the formation of a D. acuta bloom. A shift in toxin profiles of common mussels (Mytilus edulis) tested during regulatory monitoring was evident, with a proportional decrease in okadaic acid (OA) and dinophysistoxin-1 (DTX1) and an increase in dinophysistoxin-2 (DTX2) occurring when D. acuta became dominant. Routine enumeration of Dinophysis to species level could provide early warning of potential contamination of shellfish with DTX2 and thus determine the choice of the most suitable kit for effective end-product testing.


Assuntos
Bivalves/química , Dinoflagelados/isolamento & purificação , Toxinas Marinhas/análise , Ácido Okadáico/análise , Piranos/análise , Poluentes da Água/análise , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Escócia , Alimentos Marinhos/análise , Intoxicação por Frutos do Mar
19.
J Sep Sci ; 41(23): 4272-4280, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30298978

RESUMO

An analytical method for the analysis of relevant secoiridoid-based components in olive oil, oleacein and oleuropein aglycone, is described using for the first time deuterated surrogates. 0.2 g of sample was necessary to perform the analysis using liquid-liquid extraction and ultrasound-assisted extraction with a mixture of methanol/water (4:1, v/v). To avoid the formation of by-products, normal-phase ultra high performance liquid chromatography was chosen for the chromatographic separation. The selected mobile phase was a gradient mixture of tetrahydrofurane and hexane, and an ACE Excel 3 CN-ES column as stationary phase. The detection and quantification was performed with a SYNAPT G2-Si mass spectrometer. The calibration curves for oleacein and oleuropein aglycone were linear and quadratic, respectively. The validation was done at three levels of concentration. Relative errors from 0.1 to 10.5% and relative standard deviations lower than 9% were obtained. The method was applied to study different samples of olive oil.


Assuntos
Acetatos/análise , Aldeídos/análise , Azeite de Oliva/química , Fenóis/análise , Piranos/análise , Cromatografia Líquida de Alta Pressão , Monoterpenos Ciclopentânicos , Espectrometria de Massas , Estrutura Molecular
20.
Cell Physiol Biochem ; 49(2): 743-757, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30176657

RESUMO

BACKGROUND/AIMS: Okadaic acid (OA) and the structurally related compounds dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2) are marine phycotoxins that cause diarrheic shellfish poisoning (DSP) in humans due to ingestion of contaminated shellfish. In order to guarantee consumer protection, the regulatory authorities have defined the maximum level of DSP toxins as 160 µg OA equivalent kg-1 shellfish meat. For risk assessment and overall toxicity determination, knowledge of the relative toxicities of each analogue is required. In absence of enough information from human intoxications, oral toxicity in mice is the most reliable data for establishing Toxicity Equivalence Factors (TEFs). METHODS: Toxins were administered to mice by gavage, after that the symptomatology and mice mortality was registered over a period of 24 h. Organ damage data were collected at necropsy and transmission electron microscopy (TEM) was used for ultrastructural studies. Toxins in urine, feces and blood were analyzed by HPLC-MS/MS. The evaluation of in vitro potencies of OA, DTX1 and DTX2 was performed by the protein phosphatase 2A (PP2A) inhibition assay. RESULTS: Mice that received DSP toxins by gavage showed diarrhea as the main symptom. Those toxins caused similar gastrointestinal alterations as well as intestine ultrastructural changes. However, DSP toxins did not modify tight junctions to trigger diarrhea. They had different toxicokinetics and toxic potency. The lethal dose 50 (LD50) was 487 µg kg-1 bw for DTX1, 760 µg kg-1 bw for OA and 2262 µg kg-1 bw for DTX2. Therefore, the oral TEF values are: OA = 1, DTX1 = 1.5 and DTX2 = 0.3. CONCLUSION: This is the first comparative study of DSP toxins performed with accurate well-characterized standards and based on acute toxicity data. Results confirmed that DTX1 is more toxic than OA by oral route while DTX2 is less toxic. Hence, the current TEFs based on intraperitoneal toxicity should be modified. Also, the generally accepted toxic mode of action of this group of toxins needs to be reevaluated.


Assuntos
Peso Corporal/efeitos dos fármacos , Ácido Okadáico/toxicidade , Piranos/toxicidade , Administração Oral , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Coração/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/ultraestrutura , Camundongos , Miocárdio/ultraestrutura , Ácido Okadáico/análise , Ácido Okadáico/urina , Proteína Fosfatase 2/antagonistas & inibidores , Proteína Fosfatase 2/metabolismo , Piranos/análise , Piranos/urina , Estômago/efeitos dos fármacos , Estômago/patologia , Espectrometria de Massas em Tandem , Testes de Toxicidade
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