Showing papers by "Francisco A. Tomás-Barberán published in 2000"
TL;DR: HPLC-DAD and HPLC-MS analyses of the juices revealed that commercial juices contained the pomegranate tannin punicalagin while only traces of this compound were detected in the experimental juice obtained from arils in the laboratory, which shows that pomesgranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind.
Abstract: The antioxidant activity of pomegranate juices was evaluated by four different methods (ABTS, DPPH, DMPD, and FRAP) and compared to those of red wine and a green tea infusion. Commercial pomegranate juices showed an antioxidant activity (18-20 TEAC) three times higher than those of red wine and green tea (6-8 TEAC). The activity was higher in commercial juices extracted from whole pomegranates than in experimental juices obtained from the arils only (12-14 TEAC). HPLC-DAD and HPLC-MS analyses of the juices revealed that commercial juices contained the pomegranate tannin punicalagin (1500-1900 mg/L) while only traces of this compound were detected in the experimental juice obtained from arils in the laboratory. This shows that pomegranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind. This could account for the higher antioxidant activity of commercial juices compared to the experimental ones. In addition, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins were detected and quantified in the pomegranate juices.
2,139 citations
TL;DR: In this paper, the occurrence in foods of flavanones, chalcones and dihydrochalcones is reviewed. But no data for plasma or tissue levels, but both endogenous and gut flora metabolites of both classes of compound are found in urine.
Abstract: This paper reviews the occurrence in foods of flavanones, chalcones and dihydrochalcones. The major dietary sources of flavanones and dihydrochalcones are citrus fruits and apples respectively. These compounds may make a greater contribution to the total daily intake of flavonoids than the more extensively studied flavonols. There are no data for plasma or tissue levels, but both endogenous and gut flora metabolites of both classes of compound are found in urine. For these reasons, these compounds deserve greater attention in epidemiological studies.
355 citations
Abstract: Quantitative data for hydroxybenzoic acids (naturally occurring and permitted additives) and their conjugates in foods and beverages are summarised. Tea, rosaceous fruits, red wines and potatoes are important sources for which more comprehensive compositional data are required. Their absorption, metabolism, toxicological evaluation and possible biological significance are discussed. There are insufficient data to properly define the dietary burdens, but it would seem that ellagic acid and gallic acid from natural sources may dominate in many cases, although the intake of added benzoic acid may be of a similar magnitude. It is pointed out that an additional, previously overlooked and possibly significant burden, particularly of benzoic acid itself, might arise as a result of the gut flora metabolism of larger-mass dietary phenols.
© 2000 Society of Chemical Industry
251 citations
TL;DR: The results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.
Abstract: In the skin of cv. Napoleon table grapes, the anthocyanins malvidin 3-glucoside (and its acetyl and p-coumaroyl derivatives), cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and delphinidin 3-glucoside were identified by HPLC-DAD-MS. In addition, quercetin 3-glucoside and 3-glucuronide, caffeoyltartaric, piceid, and resveratrol were also detected. The content of most phenolics remained quite constant during postharvest refrigerated storage (10 days at 0 degrees C) while the resveratrol derivatives increased 2-fold. Postharvest treatments of grapes with UVC and UVB light induced a large increase in resveratrol derivatives (3- and 2-fold, respectively). This means that a serving of mature Napoleon grapes (200 g) provides approximately 1 mg of resveratrol, which is in the range of the amount supplied by a glass of red wine. This can be increased to 2 or 3 mg of resveratrol per serving in grapes that have been irradiated with UVB or UVC, respectively. These results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.
230 citations
TL;DR: Honey samples contaminated with Eucalyptus as revealed by their pollen analysis and the lack of tricetin or their glycosides in heather floral nectar remains to be established if myricetin, tricETin, and luteolin originate from Eucallyptus floralNectar where the corresponding glycoside should be present.
Abstract: European Eucalyptus honeys showed a common and characteristic HPLC profile in which the flavonoids myricetin (3,5,7,3‘,4‘,5‘-hexahydroxyflavone), tricetin (5,7,3‘,4‘,5‘-pentahydroxyflavone), quercetin (3,5,7,3‘,4‘-pentahydroxyflavone), luteolin (5,7,3‘,4‘-tetrahydroxyflavone), and kaempferol (3,5,7,4‘-tetrahydroxyflavone) were identified. Their contents, and relative amounts, in the analyzed honey samples were quite constant and supported their floral origin. In addition, ellagic acid and the propolis-derived flavonoids pinobanksin, pinocembrin, and chrysin were detected in most samples. The contents of these nonfloral phenolics were much more variable as could be expected for their propolis origin. Myricetin, tricetin, and luteolin had not been identified as floral markers in any other honey sample previously analyzed in our laboratory (chestnut, citrus, rosemary, lavender, acacia, rapeseed, sunflower, heather, lime tree, etc.) or reported in the literature, suggesting that these could be useful markers....
178 citations
TL;DR: The present results confirm the use of flavonoid analysis as an objective method for the botanical origin determination of eucalyptus honey and suggest that species-specific differences can be detected with this analysis.
Abstract: The HPLC analyses of Australian unifloral Eucalyptus honeys have shown that the flavonoids myricetin (3,5,7,3',4', 5'-hexahydroxyflavone), tricetin (5,7,3',4',5'-pentahydroxyflavone), quercetin (3,5,7,3',4'-pentahydroxyflavone), luteolin (5,7,3', 4'-tetrahydroxyflavone), and kaempferol (3,5,7, 4'-tetrahydroxyflavone) are present in all samples. These compounds were previously suggested as floral markers of European Eucalyptus honeys. The present results confirm the use of flavonoid analysis as an objective method for the botanical origin determination of eucalyptus honey. Honeys from E. camaldulensis (river red gum honey) contain tricetin as the main flavonoid marker, whereas in honeys from E. pilligaensis (mallee honey), luteolin is the main flavonoid marker, suggesting that species-specific differences can be detected with this analysis. The main difference between the flavonoid profiles of Australian and European Eucalyptus honeys is that in the Australian honeys, the propolis-derived flavonoids (pinobanksin (3,5, 7-trihydroxyflavanone), pinocembrin (5,7-dihydroxyflavanone), and chrysin (5,7-dihydroxyflavone)) are seldom found and in much smaller amounts.
125 citations
TL;DR: The flavonol content of commercial capers produced in different Mediterranean countries has been analysed and brining extracted most of the kaempferol 3-rhamnosyl rutinoside present in the original buds, this being a minor constituent in pickled capers.
Abstract: The flavonol content of commercial capers (pickled flower buds of Capparis spinosa L., C. sicula Veill. in Duham. and C. orientalis Veill. in Duham.) produced in different Mediterranean countries (Spain, Italy, Greece, Turkey and Morocco) has been analysed. The content of quercetin 3-rutinoside, kaempferol 3-rutinoside; and kaempferol 3-rhamnosyl-rutinoside as well as the aglycones (quercetin and kaempferol) were evaluated by HPLC coupled with a diode-array detector. The free aglycones were not detected in the original flower buds, indicating that they were produced during the brining process. In addition, brining extracted most of the kaempferol 3-rhamnosyl rutinoside present in the original buds, this being a minor constituent in pickled capers. The average content of flavonoid glycosides in commercial capers was 5.18 mg/g fresh weight. When this value is converted to the corresponding aglycones (quercetin and kaempferol), capers provide an average of 3.86 mg/g fresh weight. A serving of capers (10 g) will provide 65 mg of flavonoid glycosides or the equivalent 40 mg of quercetin as aglycone.
97 citations
TL;DR: In this article, a review of the antioxidant activity of phenolic metabolites is presented, as well as their bioavailability, absorption and metabolism in animals and humans, and the changes in flavonoids and other phenolic antioxidants during the post-harvest life of fruit and vegetables are evaluated.
Abstract: Flavonoids and other phenolic metabolites have important biological activities related to their antioxidant properties and, especially, to their free-radical scavenging ability. It has been suggested that dietary phenolics might be beneficial agents for the prevention of cardiovascular diseases and cancer, a suggestion supported by epidemiological and experimental studies. In the present review, the antioxidant activity of flavonoids and other phenolic metabolites is reviewed, as well as their bioavailability, absorption and metabolism in animals and humans. In addition, the flavonoid content and that of other phenolics in different fruits and vegetables is reviewed. The changes in flavonoids and other phenolic antioxidants during the postharvest life of fruit and vegetables are evaluated. The effect of storage, technological treatments (controlled atmospheres, UV irradiation, heat shocks, etc.), and processing (minimal processing, juice manufacturing, drying, cooking, canning, etc.) on the content of the biologically active phenolics is also reviewed.
96 citations