The volatile compounds of Rumexinduratus leaves were studied for the first time. In order to achi... more The volatile compounds of Rumexinduratus leaves were studied for the first time. In order to achieve the most complete volatile profile four different extractive techniques (hydrodistillation, solid-phase microextraction, Soxhlet system and direct solvent extraction) were applied. The different extracts were analysed by gas chromatography/ion trap-mass spectrometry (GC/IT-MS) which allowed the identification of 81 compounds, distributed by several chemical classes: esters, terpenes, aldehydes, acids, norisoprenoids, ketones, naphthalene derivatives, steroids derivatives and alcohols, among others. The different techniques lead to different compounds' extraction. Using hexane and dichloromethane, 9 and 4 compounds were extracted, respectively. Hydrodistillation, solid-phase microextraction and Soxhlet extraction allowed the extraction of 43, 24 and 29 compounds, respectively. Hydrodistillation was revealed to be the most effective technique, allowing the extraction of a higher number of compounds, both in the hydrolat (20 compounds) and essential oil (34 compounds), having 11 compounds in common.
A comparative study was developed on the total fatty acids composition of twelve wild edible mush... more A comparative study was developed on the total fatty acids composition of twelve wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, Cantharellus cibarius, Amanita caesarea and Hydnum rufescens). In order to define qualitative and quantitative profiles, combined fatty acids were hydrolyzed with potassium hydroxide/methanol and all free compounds were derived to their methyl ester forms with methanolic boron trifluoride, followed by analysis by GC-MS. Thirty fatty acids were determined. As far as we know, the fatty acid profiles of A. caesarea and H. rufescens are described for the first time. As for the remaining species, a high number of new compounds were identified, which much improved the knowledge about their fatty acids profiles. In general, oleic, linoleic, palmitic and stearic acids were present in highest contents. Polyunsaturated and monounsaturated fatty acids, valuable healthy compounds for humans, predominated over saturated fatty acids for all the studied mushroom species. R. cyanoxantha presented the highest fatty acids amounts, while B. edulis was the poorest species. By Agglomerative Hierarchic Cluster Analysis the studied species were gathered in 5 groups, based in their fatty acid patterns.
The effect of some viticultural parameters on the grape carotenoid profile was investigated. Grap... more The effect of some viticultural parameters on the grape carotenoid profile was investigated. Grape cultivar, ripeness stage, sunlight and shade exposure, altitude, and vegetative height were studied. Differences between cultivars were observed in eight different black grape varieties: Touriga Brasileira (TBR), Tinta Barroca (TB), Tinta Amarela (TA), Souzão (S), Touriga Franca (TF), Touriga Nacional (TN), Tinta Roriz (TR), and Tinto Cão (TC), from the Douro region. TA and TBR clearly produced higher concentrations of carotenoids. Results showed that carotenoid content decreased during ripening. Decreases of lutein were observed until 66%, whereas beta-carotene slowly decreased, having a constant level until the harvest date. Carotenoid contents were consistently higher in grapes exposed to shade than in those exposed to direct sunlight in both studied white grape varieties, Maria Gomes (MG) and Loureiro (L). In the Douro Valley, high-elevation terraces, which presented a lower temperature and higher humidity during the maturation period, appeared to produce grapes with higher carotenoid values. Grapes grown with higher vegetative height seem to have higher carotenoid levels; furthermore, grapes grown with lower vegetative height had higher weight and sugar concentrations.
ABSTRACT: The aim of this work was the simultaneous determination of both ketoacids and dicarbon... more ABSTRACT: The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect α-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of α-keto-γ-(methylthio)butyric acid and β-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 wines analyzed (white wines, Madeira wines, and Port wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for α-keto-γ-(methylthio)butyric acid and 0.1 to 9.6 mg/L for β-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already reported.
3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is an amphetamine derivative drug with entactog... more 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is an amphetamine derivative drug with entactogenic, empathogenic and hallucinogenic properties, commonly consumed at rave parties in a polydrug abuse pattern, especially with cannabis, tobacco and ethanol. Since both MDMA and ethanol may cause deleterious effects to the liver, the evaluation of their putative hepatotoxic interaction is of great interest, especially considering that most of the MDMA users are regular ethanol consumers.Thus, the aim of the present study was to evaluate, in vivo, the acute hepatotoxic effects of MDMA (10 mg/kg i.p.) in CD-1 mice previously exposed to 12% ethanol as drinking fluid (for 8 weeks). Body temperature was continuously measured for 12 h after MDMA administration and, after 24 h, hepatic damage was evaluated.The administration of MDMA to non pre-treated mice resulted in sustained hyperthermia, which was significantly increased in ethanol pre-exposed mice. A correspondent higher increase of hepatic heat shock transcription factor (HSF-1) activation was also observed in the latter group. Furthermore, MDMA administration resulted in liver damage as confirmed by histological analysis, slight decrease in liver weight and increased plasma transaminases levels. These hepatotoxic effects were also exacerbated when mice were pre-treated with ethanol. The activities of some antioxidant enzymes (such as SOD, GPx and Catalase) were modified by ethanol, MDMA and their joint action. The hepatotoxicity resulting from the simultaneous exposure to MDMA and ethanol was associated with a higher activation of NF-κB, indicating a pro-inflammatory effect in this organ.In conclusion, the obtained results strongly suggest that the consumption of ethanol increases the hyperthermic and hepatotoxic effects associated with MDMA abuse.
Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-... more Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-DAD and HPLC-DAD-MS (ESP+) analysis. A total of 13 carotenoid and chlorophyll-derived compounds are formally reported in grapes, 3 are identified for the first time, pheophytins a and b and (13Z)-beta-carotene, and 3 others remain unknown. In Port wines 19 compounds with carotenoid or chlorophyll-like structures are present, 8 still unidentified. The young wines showed higher total carotenoid content and chlorophyll-like compounds compared to aged Ports, with lutein and beta-carotene as major carotenoids. Among samples analyzed of monovarietal Vitis vinifera L. cultivar wines produced with the five most important Douro varieties, Tinta Roriz contained the highest levels of carotenoids and Touriga Franca the lowest. The forced-aging study indicated that lutein was more sensitive to temperature than beta-carotene. Additionally, aged wines showed higher ratios of beta-carotene/lutein concentrations compared to new Ports. Rates of degradation of chlorophyll derivative compounds were higher than those for carotene and lutein.
The carotenoids degradation and the formation of volatiles were examined by simulating Port wine ... more The carotenoids degradation and the formation of volatiles were examined by simulating Port wine aging. A two year old red Port wine was saturated with oxygen, supplemented with lutein and β-carotene and kept at 60 °C during 87 h. A similar study was performed in a model wine solution. Results showed that the percentage decrease in lutein levels was, respectively, 79% and 95%, in the wine model solution and in the Port wine, and 55% and 10% for β-carotene, indicating that lutein was more sensitive to degradation than β-carotene. Two other unknown degradation carotenoid compounds were identified by HPLC/DAD (reverse phase λmax: 422; 445; 475 and 422; 445; 472) in the lutein supplemented wine. Levels of β-ionone and β-cyclocitral increased (2.5 times) in both, wine and wine model solution, supplemented with β-carotene. Along with these compounds, the same behaviour was observed in β-damascenone in the supplemented lutein wine and wine model solution. New insights were provided into the understanding of aroma modifications occurring during Port wine aging. The relationship between carotenoid molecules (β-carotene and lutein) and some volatiles has also been provided.
ABSTRACT The aim of this work was to characterize 8 representative grape varieties of the Douro R... more ABSTRACT The aim of this work was to characterize 8 representative grape varieties of the Douro Region using the carotenoid profile as it relates to aromatic compounds in the respective wines. Some other analyses, such as the determination of sugar, probable alcohol, pH, and total acidity, were also performed in an attempt to understand in which way the evaluated characteristics influenced by grape variety could contribute to the wine aroma. For the 3 y of the study, grape varieties with higher concentrations of carotenoids (Touriga Femea, Tinta Amarela, and Tinta Barroca) have lower values of free norisoprenoids, even with exceptions (Touriga Femea). Conversely, grape varieties with lower concentrations of carotenoids (Touriga Nacional, Sousao, and Tinto Cao) appear to have higher contents of free norisoprenoids, namely b-ionone for Touriga Nacional and vitispirane and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) for Sousao and Tinto Cao. Touriga Nacional, followed by Touriga Femea, was the wine variety with the highest values of total free terpenols (linalol, a-terpineol, nerol, and geraniol), the presence of which is responsible for the floral aroma.
Volatile sulfur compounds of 15 young port wines and 12 old port wines were determined. As there ... more Volatile sulfur compounds of 15 young port wines and 12 old port wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol. The synergistic effects of increasing temperature and O(2) at lower pH had the largest impact. Dimethyl sulfide was formed during the experimental period in the presence of O(2). Dimethyl sulfone had the same behavior. Methionol decreased significantly in the presence of O(2), but no methional was formed. 2-Mercaptoethanol, considered to be an important "off-flavor" in dry wines, also decreased during the experimental period (54 days) in the presence of O(2), and the respective disulfide was formed. These results corroborate the fact that old port wine (barrel aged) never develops "off-flavors" associated with the presence of methionol (cauliflower), 2-mercaptoethanol (rubber/burnt), or methional (cooked potato). In fact, temperature and oxygen are the major factors in the consumption of these molecules. However, some notes of "quince" and "metallic" can appear during port wine aging, and these can be associated with the presence of dimethyl sulfide.
Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat... more Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the anti-thrombogenic properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2–3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the charge-transfer complexes with m/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ.
The negative effects of oxygen on white wine quality and the various factors which influence it (... more The negative effects of oxygen on white wine quality and the various factors which influence it (including temperature, dissolved oxygen, pH, and free SO(2)) are well documented both at the sensory and compositional levels. What is less defined is the quantitative relationship between these parameters and the kinetics of the development of the negative effects of oxidation. The experiment presented here attempts to generate data which can be used to predictively model the oxidative degradation of white wines. Bottled wines were submitted to extreme conditions (45 degrees C temperature, O(2) saturation) during 3 months witth samples taken every 15 days for both sensorial and chemical analysis (GC-O/FPD/MS, 420 nm). The synergistic effects of increasing temperature and O(2) at lower pH are evident, both on the decrease in levels of terpene alcohols and norisoprenoids (which impart floral aromas), and on the development of off-flavors such as "honey-like", "boiled-potato", and…
The volatile compounds of Rumexinduratus leaves were studied for the first time. In order to achi... more The volatile compounds of Rumexinduratus leaves were studied for the first time. In order to achieve the most complete volatile profile four different extractive techniques (hydrodistillation, solid-phase microextraction, Soxhlet system and direct solvent extraction) were applied. The different extracts were analysed by gas chromatography/ion trap-mass spectrometry (GC/IT-MS) which allowed the identification of 81 compounds, distributed by several chemical classes: esters, terpenes, aldehydes, acids, norisoprenoids, ketones, naphthalene derivatives, steroids derivatives and alcohols, among others. The different techniques lead to different compounds' extraction. Using hexane and dichloromethane, 9 and 4 compounds were extracted, respectively. Hydrodistillation, solid-phase microextraction and Soxhlet extraction allowed the extraction of 43, 24 and 29 compounds, respectively. Hydrodistillation was revealed to be the most effective technique, allowing the extraction of a higher number of compounds, both in the hydrolat (20 compounds) and essential oil (34 compounds), having 11 compounds in common.
A comparative study was developed on the total fatty acids composition of twelve wild edible mush... more A comparative study was developed on the total fatty acids composition of twelve wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, Cantharellus cibarius, Amanita caesarea and Hydnum rufescens). In order to define qualitative and quantitative profiles, combined fatty acids were hydrolyzed with potassium hydroxide/methanol and all free compounds were derived to their methyl ester forms with methanolic boron trifluoride, followed by analysis by GC-MS. Thirty fatty acids were determined. As far as we know, the fatty acid profiles of A. caesarea and H. rufescens are described for the first time. As for the remaining species, a high number of new compounds were identified, which much improved the knowledge about their fatty acids profiles. In general, oleic, linoleic, palmitic and stearic acids were present in highest contents. Polyunsaturated and monounsaturated fatty acids, valuable healthy compounds for humans, predominated over saturated fatty acids for all the studied mushroom species. R. cyanoxantha presented the highest fatty acids amounts, while B. edulis was the poorest species. By Agglomerative Hierarchic Cluster Analysis the studied species were gathered in 5 groups, based in their fatty acid patterns.
The effect of some viticultural parameters on the grape carotenoid profile was investigated. Grap... more The effect of some viticultural parameters on the grape carotenoid profile was investigated. Grape cultivar, ripeness stage, sunlight and shade exposure, altitude, and vegetative height were studied. Differences between cultivars were observed in eight different black grape varieties: Touriga Brasileira (TBR), Tinta Barroca (TB), Tinta Amarela (TA), Souzão (S), Touriga Franca (TF), Touriga Nacional (TN), Tinta Roriz (TR), and Tinto Cão (TC), from the Douro region. TA and TBR clearly produced higher concentrations of carotenoids. Results showed that carotenoid content decreased during ripening. Decreases of lutein were observed until 66%, whereas beta-carotene slowly decreased, having a constant level until the harvest date. Carotenoid contents were consistently higher in grapes exposed to shade than in those exposed to direct sunlight in both studied white grape varieties, Maria Gomes (MG) and Loureiro (L). In the Douro Valley, high-elevation terraces, which presented a lower temperature and higher humidity during the maturation period, appeared to produce grapes with higher carotenoid values. Grapes grown with higher vegetative height seem to have higher carotenoid levels; furthermore, grapes grown with lower vegetative height had higher weight and sugar concentrations.
ABSTRACT: The aim of this work was the simultaneous determination of both ketoacids and dicarbon... more ABSTRACT: The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect α-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of α-keto-γ-(methylthio)butyric acid and β-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 wines analyzed (white wines, Madeira wines, and Port wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for α-keto-γ-(methylthio)butyric acid and 0.1 to 9.6 mg/L for β-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already reported.
3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is an amphetamine derivative drug with entactog... more 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is an amphetamine derivative drug with entactogenic, empathogenic and hallucinogenic properties, commonly consumed at rave parties in a polydrug abuse pattern, especially with cannabis, tobacco and ethanol. Since both MDMA and ethanol may cause deleterious effects to the liver, the evaluation of their putative hepatotoxic interaction is of great interest, especially considering that most of the MDMA users are regular ethanol consumers.Thus, the aim of the present study was to evaluate, in vivo, the acute hepatotoxic effects of MDMA (10 mg/kg i.p.) in CD-1 mice previously exposed to 12% ethanol as drinking fluid (for 8 weeks). Body temperature was continuously measured for 12 h after MDMA administration and, after 24 h, hepatic damage was evaluated.The administration of MDMA to non pre-treated mice resulted in sustained hyperthermia, which was significantly increased in ethanol pre-exposed mice. A correspondent higher increase of hepatic heat shock transcription factor (HSF-1) activation was also observed in the latter group. Furthermore, MDMA administration resulted in liver damage as confirmed by histological analysis, slight decrease in liver weight and increased plasma transaminases levels. These hepatotoxic effects were also exacerbated when mice were pre-treated with ethanol. The activities of some antioxidant enzymes (such as SOD, GPx and Catalase) were modified by ethanol, MDMA and their joint action. The hepatotoxicity resulting from the simultaneous exposure to MDMA and ethanol was associated with a higher activation of NF-κB, indicating a pro-inflammatory effect in this organ.In conclusion, the obtained results strongly suggest that the consumption of ethanol increases the hyperthermic and hepatotoxic effects associated with MDMA abuse.
Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-... more Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-DAD and HPLC-DAD-MS (ESP+) analysis. A total of 13 carotenoid and chlorophyll-derived compounds are formally reported in grapes, 3 are identified for the first time, pheophytins a and b and (13Z)-beta-carotene, and 3 others remain unknown. In Port wines 19 compounds with carotenoid or chlorophyll-like structures are present, 8 still unidentified. The young wines showed higher total carotenoid content and chlorophyll-like compounds compared to aged Ports, with lutein and beta-carotene as major carotenoids. Among samples analyzed of monovarietal Vitis vinifera L. cultivar wines produced with the five most important Douro varieties, Tinta Roriz contained the highest levels of carotenoids and Touriga Franca the lowest. The forced-aging study indicated that lutein was more sensitive to temperature than beta-carotene. Additionally, aged wines showed higher ratios of beta-carotene/lutein concentrations compared to new Ports. Rates of degradation of chlorophyll derivative compounds were higher than those for carotene and lutein.
The carotenoids degradation and the formation of volatiles were examined by simulating Port wine ... more The carotenoids degradation and the formation of volatiles were examined by simulating Port wine aging. A two year old red Port wine was saturated with oxygen, supplemented with lutein and β-carotene and kept at 60 °C during 87 h. A similar study was performed in a model wine solution. Results showed that the percentage decrease in lutein levels was, respectively, 79% and 95%, in the wine model solution and in the Port wine, and 55% and 10% for β-carotene, indicating that lutein was more sensitive to degradation than β-carotene. Two other unknown degradation carotenoid compounds were identified by HPLC/DAD (reverse phase λmax: 422; 445; 475 and 422; 445; 472) in the lutein supplemented wine. Levels of β-ionone and β-cyclocitral increased (2.5 times) in both, wine and wine model solution, supplemented with β-carotene. Along with these compounds, the same behaviour was observed in β-damascenone in the supplemented lutein wine and wine model solution. New insights were provided into the understanding of aroma modifications occurring during Port wine aging. The relationship between carotenoid molecules (β-carotene and lutein) and some volatiles has also been provided.
ABSTRACT The aim of this work was to characterize 8 representative grape varieties of the Douro R... more ABSTRACT The aim of this work was to characterize 8 representative grape varieties of the Douro Region using the carotenoid profile as it relates to aromatic compounds in the respective wines. Some other analyses, such as the determination of sugar, probable alcohol, pH, and total acidity, were also performed in an attempt to understand in which way the evaluated characteristics influenced by grape variety could contribute to the wine aroma. For the 3 y of the study, grape varieties with higher concentrations of carotenoids (Touriga Femea, Tinta Amarela, and Tinta Barroca) have lower values of free norisoprenoids, even with exceptions (Touriga Femea). Conversely, grape varieties with lower concentrations of carotenoids (Touriga Nacional, Sousao, and Tinto Cao) appear to have higher contents of free norisoprenoids, namely b-ionone for Touriga Nacional and vitispirane and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) for Sousao and Tinto Cao. Touriga Nacional, followed by Touriga Femea, was the wine variety with the highest values of total free terpenols (linalol, a-terpineol, nerol, and geraniol), the presence of which is responsible for the floral aroma.
Volatile sulfur compounds of 15 young port wines and 12 old port wines were determined. As there ... more Volatile sulfur compounds of 15 young port wines and 12 old port wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol. The synergistic effects of increasing temperature and O(2) at lower pH had the largest impact. Dimethyl sulfide was formed during the experimental period in the presence of O(2). Dimethyl sulfone had the same behavior. Methionol decreased significantly in the presence of O(2), but no methional was formed. 2-Mercaptoethanol, considered to be an important "off-flavor" in dry wines, also decreased during the experimental period (54 days) in the presence of O(2), and the respective disulfide was formed. These results corroborate the fact that old port wine (barrel aged) never develops "off-flavors" associated with the presence of methionol (cauliflower), 2-mercaptoethanol (rubber/burnt), or methional (cooked potato). In fact, temperature and oxygen are the major factors in the consumption of these molecules. However, some notes of "quince" and "metallic" can appear during port wine aging, and these can be associated with the presence of dimethyl sulfide.
Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat... more Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the anti-thrombogenic properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2–3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the charge-transfer complexes with m/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ.
The negative effects of oxygen on white wine quality and the various factors which influence it (... more The negative effects of oxygen on white wine quality and the various factors which influence it (including temperature, dissolved oxygen, pH, and free SO(2)) are well documented both at the sensory and compositional levels. What is less defined is the quantitative relationship between these parameters and the kinetics of the development of the negative effects of oxidation. The experiment presented here attempts to generate data which can be used to predictively model the oxidative degradation of white wines. Bottled wines were submitted to extreme conditions (45 degrees C temperature, O(2) saturation) during 3 months witth samples taken every 15 days for both sensorial and chemical analysis (GC-O/FPD/MS, 420 nm). The synergistic effects of increasing temperature and O(2) at lower pH are evident, both on the decrease in levels of terpene alcohols and norisoprenoids (which impart floral aromas), and on the development of off-flavors such as "honey-like", "boiled-potato", and…
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