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Eduardo Lissi - One of the best experts on this subject based on the ideXlab platform.
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protective effect of Boldo and tea infusions on the visible light mediated pro oxidant effects of vitamin b2 riboflavin
Photochemistry and Photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
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Protective Effect of Boldo and Tea Infusions on the Visible Light–mediated Pro-oxidant Effects of Vitamin B2, Riboflavin¶
Photochemistry and photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
J.m. Del Valle - One of the best experts on this subject based on the ideXlab platform.
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Effect of Boldo (Peumus boldus M.) pretreatment on kinetics of supercritical CO2 extraction of essential oil
Journal of Food Engineering, 2012Co-Authors: Edgar Uquiche, Elizabeth Huerta, Alicia Sandoval, J.m. Del ValleAbstract:Abstract This work examined the effect of the solid matrix on supercritical carbon dioxide (SC CO 2 ) extraction of essentials oils from Boldo leaves ( Peumus boldus M.) subjected to rapid decompression of a CO 2 -impregnated sample, conventional milling, and low-temperature milling. Low-temperature conditioning prior to milling decreased heat-driven losses of volatile compounds during milling, as attested by a higher extract yield for low-temperature (10.8 g extract/kg extract-free substrate) than conventionally (9.63 g/kg) milled sample. Extract yield was even larger for the rapidly decompressed sample (11.4 g/kg). Results of SC CO 2 extraction experiments carried out at 40 °C and 10 MPa were adjusted to a diffusional model using the effective diffusivity of the extract in the solid matrix ( D e ) and a single partition of essential oils between solid substrate and SC CO 2 as best-fitting parameters. A microstructural factor ( F M ), which was estimated as the ratio between the binary diffusion coefficient of the essential oil in SC-CO 2 under extraction conditions and D e , was used to characterize the effect of sample pretreatment on extraction rates. Values of F M for rapidly decompressed (202) and low-temperature milled (1740) samples were smaller than value for conventionally milled samples (2200), which revealed that the two first treatments disrupted secretory cavities in Boldo leaves more effectively than the third. This was confirmed by light microscopy observations. The work included also measurements using oregano bracts ( Origanum vulgare L.) as the substrate to confirm literature reports on the SC CO 2 extraction of pretreated bracts and to serve as a reference to our main results with Boldo leaves. Trends with oregano coincided with those of Boldo.
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Antioxidant Activity of Crude Extract, Alkaloid Fraction, and Flavonoid Fraction from Boldo (Peumus boldus Molina) Leaves
Journal of Food Science, 2006Co-Authors: Nathalie Quezada, J.m. Del Valle, M. Asencio, José Miguel Aguilera, Bernardino GómezAbstract:ABSTRACT: Boldo is an endemic plant from Chile widely used in folk medicine, whose biological (mainly antioxidant) activity has been attributed to the presence of the alkaloid boldine. The aim of this study was to determine the contribution of the flavonoid and other crude fractions from Boldo leaves to the antioxidant activity of extracts. The main constituent in the flavonoid fraction was also isolated. The antioxidant activity and reducing power of crude Boldo extract and fractions were measured and compared with natural and synthetic antioxidants. The antioxidant activity of Boldo leaf extracts came mainly from the flavonoid fraction (44.1%) followed by the alkaloid fraction (15.6%), with catechin and boldine being the main contributors of the antioxidant activity of these 2 fractions (60.9% and 35.6% of the total activity, respectively). On the basis of these results, we propose to use catechin and boldine as markers for the antioxidant activity of Boldo leaves. Tailor-made antioxidants to be used in foods can be prepared by enriching these 2 fractions.
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Solubility of Boldo leaf antioxidant components (Boldine) in high-pressure carbon dioxide
Fluid Phase Equilibria, 2005Co-Authors: Juan C. De La Fuente, Natalie Quezada, J.m. Del ValleAbstract:Abstract This work contributes to the development of an enrichment process for antioxidant compounds in aqueous alcoholic extracts of Boldo (Peumus boldus M.) leaves by using high-pressure CO2 as the solvent. Specifically we measured the high-pressure solubility (y2, molar fraction) of a selected bioactive compound in Boldo leaves (boldine) in CO2 as a function of system temperature (298 K ≤ T ≤ 333 K) and pressure (8 MPa ≤ P ≤ 40 MPa). Experimental data was correlated by using a density-based model which is valid for solvent densities >607 kg/m3. Predicted solubility values are low (4 × 10−7 ≤ y2 ≤ 6 × 10−5) but comparable with those of nitrogen-containing organic compounds with similar molecular weight (327.4 Da) and solubility parameter (28.3 MPa0.5 at 313 K) as boldine.
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Recovery of antioxidants from Boldo (Peumus boldus M.) by conventional and supercritical CO2 extraction
Food Research International, 2004Co-Authors: J.m. Del Valle, C. Godoy, M. Asencio, José Miguel AguileraAbstract:Abstract Boldo ( Peumus boldus M.) is a native plant from Chile that has been used is traditional medicine to treat digestive and/or hepatobiliary disorders. An attempt was made in this work to extract antioxidant compounds from Boldo using conventional solvents and supercritical carbon dioxide (SCCO 2 ). Yield of soluble solids (SS), boldine, and compounds with antioxidant activity varied depending on part plant, solvent and extraction conditions. Following 24 h extraction, the highest yield was 33.4% (w/w, dry basis) of SS with 70:30 ethanol/water (v/v) mixture at 70 °C. Yield of alcoholic extractions increased as the temperature was raised from 20 to 70 °C, but the total antioxidant activity (free radical DPPH method) was maximal in Boldo leaf extracts with aqueous ethanol at 50 °C (1648 TEAC/g dry leaf). Boldine concentration was maximal (12%) in Boldo bark extracted with acidulated water, and decreased with extraction time when methanol or ethanol/water mixtures were used. No boldine was detected in Boldo leaf extracts. The contribution of boldine to the antioxidant activity of Boldo extracts was low, specially when using aqueous ethanol as solvent, and/or Boldo leaf instead of Boldo bark as substrate. Yield of SCCO 2 extraction was ≈3% SS. Only non-polar compounds with limited antioxidant activity (0.08 TEAC/g extract) were extracted by SCCO 2 .
Eduardo Silva - One of the best experts on this subject based on the ideXlab platform.
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protective effect of Boldo and tea infusions on the visible light mediated pro oxidant effects of vitamin b2 riboflavin
Photochemistry and Photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
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Protective Effect of Boldo and Tea Infusions on the Visible Light–mediated Pro-oxidant Effects of Vitamin B2, Riboflavin¶
Photochemistry and photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
J.r. De La Fuente - One of the best experts on this subject based on the ideXlab platform.
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protective effect of Boldo and tea infusions on the visible light mediated pro oxidant effects of vitamin b2 riboflavin
Photochemistry and Photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
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Protective Effect of Boldo and Tea Infusions on the Visible Light–mediated Pro-oxidant Effects of Vitamin B2, Riboflavin¶
Photochemistry and photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
Else Lemp - One of the best experts on this subject based on the ideXlab platform.
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protective effect of Boldo and tea infusions on the visible light mediated pro oxidant effects of vitamin b2 riboflavin
Photochemistry and Photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.
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Protective Effect of Boldo and Tea Infusions on the Visible Light–mediated Pro-oxidant Effects of Vitamin B2, Riboflavin¶
Photochemistry and photobiology, 2002Co-Authors: Eduardo Silva, M. Jopia, Ana María Edwards, Else Lemp, J.r. De La Fuente, Eduardo LissiAbstract:The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.