Background Dietary polyphenols like quercetin and rutin are considered beneficial because of thei... more Background Dietary polyphenols like quercetin and rutin are considered beneficial because of their potential protective role in the pathogenesis of multiple diseases associated to oxidative stress such as cancer, coronary heart disease and atherosclerosis. However, many of these effects may depend on the concentration of the polyphenol utilized since high doses of some phenolic compounds may be prooxidant and negatively affect cell growth and viability. Aim of the study To test the potential chemoprotective effects of quercetin and rutin, two flavonols with high antioxidant capacity, on cell growth, viability and the response of the antioxidant defense system of a human hepatoma cell line (HepG2). Methods Cell growth was measured by diaminobenzoic acid and bromodeoxyuridine assays, cell toxicity by lactate dehydrogenase leakage assay, reduced glutathione was quantified by a fluorimetric assay, cellular malondialdehyde was analyzed by high–performance liquid chromatography, reactive oxygen species were quantified by the dichlorofluorescein assay, antioxidant enzyme activities were determined by spectrophotometric analysis and their gene expression by northern blot. Results Short-term exposure (4 h) to these flavonols had no antiproliferative nor cytotoxic effect. High doses of quercetin (50–100 µM) increased glutathione concentration and gene expression of Cu/Zn superoxide dismutase and catalase inhibiting the activity of the latter enzyme, whereas lower doses (0.1–1 µM) decreased gene expression of Cu/Zn superoxide dismutase and increased that of glutathione peroxidase. All doses of quercetin and rutin diminished reactive oxygen species and high doses (10–100 µM) decreased malondialdehyde concentration. Conclusion The results indicate that both natural antioxidants induce favorable changes in the antioxidant defense system of cultured HepG2 that prevent or delay conditions which favor cellular oxidative stress.
Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultraf... more Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultrafiltration, subsequently digested by simulating a gastric plus pancreatic digestive condition and partly characterized by CZE, gel-filtration and browning. The objective of the present study was to investigate the potential protective effect of the coffee melanoidin submitted to gastrointestinal digestion on cell viability (lactate dehydrogenase leakage) and redox status of cultured human hepatoma HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of antioxidant enzymes glutathione peroxidase (GPx) and reductase (GR) were used as markers of cellular oxidative status. Pretreatment of cultured HepG2 cells with 0.5–10 μg/mL digested coffee melanoidin (DCM) for 2 or 20 h completely prevented the increase in cell damage and GR and partly prevented the decrease of GSH and the increase of MDA and GPx evoked by t-BOOH in HepG2 cells. In contrast, increased ROS generation induced by t-BOOH was not prevented when cells were pretreated with DCM. The results show that treatment of HepG2 cells with concentrations of DCM within the expected physiological range confers the cells a significant protection against an oxidative insult.
... Faki et al., 1984). Increased starch digestibilities have also been reported by other authors... more ... Faki et al., 1984). Increased starch digestibilities have also been reported by other authors in germinated legumes (Kaur and Kapoor, 1990; Subbulakshmi et al., 1976;Urooj and Puttaraj, 1994; Veena et al., 1995). As to the ...
Journal of The Science of Food and Agriculture, 1994
The composition of mesquite pods (Prosopis pallida L) (PP), a legume cultivated in the large dese... more The composition of mesquite pods (Prosopis pallida L) (PP), a legume cultivated in the large desert areas of Peru, was studied. These fruits have at the present time very little practical or commercial use. Taking into account the morphological and compositional similarities to Mediterranean carob pods (Ceratonia siliqua L) (CS), which are widely used in the food industry, some applications of PP are considered. PP shows better nutritional properties than CS, mainly owing to its lower polyphenolic content and higher protein digestibility.
The present study was aimed at evaluating the in vivo effects in rats of a diet rich in antioxida... more The present study was aimed at evaluating the in vivo effects in rats of a diet rich in antioxidant dietary fiber (AODF) from grapes on antioxidant (glutathione) concentration, antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase and superoxide dismutase) ...
In a modified method for measuring Resistant Starch (RS) in dietary fiber residues all operations... more In a modified method for measuring Resistant Starch (RS) in dietary fiber residues all operations for obtaining fiber residues and determination of RS were performed in a 50 mL centrifugation tube. This minimized error sources and simplified previous methodology.
A comparative study between dietary fiber (DF) and polyphenols (PP) in terms of degradability and... more A comparative study between dietary fiber (DF) and polyphenols (PP) in terms of degradability and physiological properties was performed. Eight groups of Wistar rats were fed either a control diet free of DF and PP or diets containing DF constituents [cellulose (C), pectins (P), and ...
Background Dietary polyphenols like quercetin and rutin are considered beneficial because of thei... more Background Dietary polyphenols like quercetin and rutin are considered beneficial because of their potential protective role in the pathogenesis of multiple diseases associated to oxidative stress such as cancer, coronary heart disease and atherosclerosis. However, many of these effects may depend on the concentration of the polyphenol utilized since high doses of some phenolic compounds may be prooxidant and negatively affect cell growth and viability. Aim of the study To test the potential chemoprotective effects of quercetin and rutin, two flavonols with high antioxidant capacity, on cell growth, viability and the response of the antioxidant defense system of a human hepatoma cell line (HepG2). Methods Cell growth was measured by diaminobenzoic acid and bromodeoxyuridine assays, cell toxicity by lactate dehydrogenase leakage assay, reduced glutathione was quantified by a fluorimetric assay, cellular malondialdehyde was analyzed by high–performance liquid chromatography, reactive oxygen species were quantified by the dichlorofluorescein assay, antioxidant enzyme activities were determined by spectrophotometric analysis and their gene expression by northern blot. Results Short-term exposure (4 h) to these flavonols had no antiproliferative nor cytotoxic effect. High doses of quercetin (50–100 µM) increased glutathione concentration and gene expression of Cu/Zn superoxide dismutase and catalase inhibiting the activity of the latter enzyme, whereas lower doses (0.1–1 µM) decreased gene expression of Cu/Zn superoxide dismutase and increased that of glutathione peroxidase. All doses of quercetin and rutin diminished reactive oxygen species and high doses (10–100 µM) decreased malondialdehyde concentration. Conclusion The results indicate that both natural antioxidants induce favorable changes in the antioxidant defense system of cultured HepG2 that prevent or delay conditions which favor cellular oxidative stress.
Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultraf... more Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultrafiltration, subsequently digested by simulating a gastric plus pancreatic digestive condition and partly characterized by CZE, gel-filtration and browning. The objective of the present study was to investigate the potential protective effect of the coffee melanoidin submitted to gastrointestinal digestion on cell viability (lactate dehydrogenase leakage) and redox status of cultured human hepatoma HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of antioxidant enzymes glutathione peroxidase (GPx) and reductase (GR) were used as markers of cellular oxidative status. Pretreatment of cultured HepG2 cells with 0.5–10 μg/mL digested coffee melanoidin (DCM) for 2 or 20 h completely prevented the increase in cell damage and GR and partly prevented the decrease of GSH and the increase of MDA and GPx evoked by t-BOOH in HepG2 cells. In contrast, increased ROS generation induced by t-BOOH was not prevented when cells were pretreated with DCM. The results show that treatment of HepG2 cells with concentrations of DCM within the expected physiological range confers the cells a significant protection against an oxidative insult.
... Faki et al., 1984). Increased starch digestibilities have also been reported by other authors... more ... Faki et al., 1984). Increased starch digestibilities have also been reported by other authors in germinated legumes (Kaur and Kapoor, 1990; Subbulakshmi et al., 1976;Urooj and Puttaraj, 1994; Veena et al., 1995). As to the ...
Journal of The Science of Food and Agriculture, 1994
The composition of mesquite pods (Prosopis pallida L) (PP), a legume cultivated in the large dese... more The composition of mesquite pods (Prosopis pallida L) (PP), a legume cultivated in the large desert areas of Peru, was studied. These fruits have at the present time very little practical or commercial use. Taking into account the morphological and compositional similarities to Mediterranean carob pods (Ceratonia siliqua L) (CS), which are widely used in the food industry, some applications of PP are considered. PP shows better nutritional properties than CS, mainly owing to its lower polyphenolic content and higher protein digestibility.
The present study was aimed at evaluating the in vivo effects in rats of a diet rich in antioxida... more The present study was aimed at evaluating the in vivo effects in rats of a diet rich in antioxidant dietary fiber (AODF) from grapes on antioxidant (glutathione) concentration, antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase and superoxide dismutase) ...
In a modified method for measuring Resistant Starch (RS) in dietary fiber residues all operations... more In a modified method for measuring Resistant Starch (RS) in dietary fiber residues all operations for obtaining fiber residues and determination of RS were performed in a 50 mL centrifugation tube. This minimized error sources and simplified previous methodology.
A comparative study between dietary fiber (DF) and polyphenols (PP) in terms of degradability and... more A comparative study between dietary fiber (DF) and polyphenols (PP) in terms of degradability and physiological properties was performed. Eight groups of Wistar rats were fed either a control diet free of DF and PP or diets containing DF constituents [cellulose (C), pectins (P), and ...
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