Characterization of anthocyanins in grape juices by ion trap liquid chromatography-mass spectrometry

A reverse phase HPLC and electrospray interface with ion trap mass spectrometer method was developed for the characterization of anthocyanins in Concord, Rubired, and Salvador grape juices. Rubired and Salvador grapes are hybrids from Vitis vinifera and Vitis rupestris. Concord grape is a grape from the native American cultivar Vitis labrusca. Individual anthocyanins in these three varieties were identified on the basis of UV-vis and MS spectra and further elucidated by MS/MS spectra. Anthocyanins in Salvador and Concord grapes were 3-O-glucosides, 3-O-(6' '-O-p-coumaroyl)glucosides, 3-O-(6' '-O-p-acetyl)glucosides, 3,5-O-diglucosides, and 3-O-(6' '-O-p-coumaroyl)-5-O-diglucosides of delphinidin, cyanidin, petunidin, peonidin, and malvidin. Vitisin B was detected in Salvador grape juice. Anthocyanins in Rubired grape juice were primarily anthocyanin diglucosides: peonidin 3,5-O-diglucoside, malvidin 3,5-O-diglucoside, peonidin 3-O-(6' '-O-p-coumaroyl)-5-O-diglucoside, and malvidin 3-O-(6' '-O-p-coumaroyl)-5-O-diglucoside are the four major anthocyanins. The presence of pelargonidin 3-O-glucoside, not previously reported, has been established for the first time in all three juices.     

Phenolic composition of the edible parts (flesh and skin) of Bordô grape (Vitis labrusca) using HPLC-DAD-ESI-MS/MS

The aim of this study was the detailed characterization of the phenolic composition and the determination of the antioxidant activity of the Bord? grape (Vitis labrusca) cultivated in South Brazil. The edible parts of Bord? grapes (flesh and skin) contained 1130 mg/kg of total phenolic compounds (as gallic acid), mainly located in the skins. Anthocyanin content in the skins was high, largely as 3,5-diglucosides (1359 mg/kg, as malvidin 3,5-diglucoside). Total flavonols accounted for 154 μmol/kg, mainly located in the skins and with myricetin 3-glucoside as the principal flavonol in both grape parts. Very low amounts of flavan-3-ol monomers and dimers and low amounts of polymeric proanthocyanidins, with a composition similar to that reported for V. vinifera grape varieties, were found in Bord? grape skins. Hydroxycinnamic acid derivatives mainly derived from caffeic acid and were found in the skins in high amounts, ten times higher than in the flesh (total amount: 483 μmol/kg). Finally, the Bord? grape cultivar can be considered a high resveratrol producer (10.91 mg/kg) and also exhibited a high value of total antioxidant capacity (37.6 ± 1.0 mmol/kg, as Trolox).     

Major flavonoids in grape seeds and skins: antioxidant capacity of catechin, epicatechin, and gallic acid

Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds.     

Antioxidant properties of pearled barley fractions

Two barley varieties (Falcon and AC Metcalfe) were separated by pearling into seven fractions and subsequently extracted with 80% methanol. The extracts, after solvent removal, were evaluated for their radical scavenging efficacy using Trolox equivalent antioxidant capacity (TEAC). The radical scavenging capacity of the extracts was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, oxygen radical absorbance capacity (ORAC(FL)), and superoxide radical assays and a photoinduced chemiluminescence technique. In both barley varieties the outermost fraction (F1) yielded the highest phenolic content. In general, Falcon had a significantly higher total phenolic content than AC Metcalfe. A similar trend was observed for TEAC, DPPH, and superoxide radical scavenging capacities of the extracts. The contents of water-soluble antioxidants of Falcon and AC Metcalfe were 1.15-12.98 and 2.20-12.25 micromol of Trolox equiv/(g of defatted material), while the corresponding lipid-soluble counterparts varied from 1.44 to 4.70 micromol of alpha-tocopherol equiv/(g of defatted material). Phenolic acids, namely, vanillic, caffeic, p-coumaric, ferulic, and sinapic acids, were identified by HPLC in barley fractions.     

Carotenoid, tocopherol, phenolic acid, and antioxidant properties of Maryland-grown soft wheat

Consumers' desires to either reduce the risk of or manage a specific health condition through improved diet have stimulated the research of agricultural products for their potential health beneficial components such as tocopherols and natural antioxidants. Soft wheat is one of the major crops in Maryland, with little information available about its potentially beneficial components. This study examined eight selected Maryland-grown soft wheat varieties or experimental lines for their potential beneficial components including tocopherols, carotenoids, total phenolics and phenolic acids and their antioxidant properties, including Fe(2+) chelating capacity and free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*) ), radical cation ABTS(*)(+), and oxygen radical (ORAC). The results showed that all tested soft wheat grain samples contained alpha-tocopherol, with a range of 3.4-10.1 microg/g. Lutein was the primary carotenoid present in the grain samples at a level of 0.82-1.14 microg/g, along with significant amounts of zeaxanthin and beta-carotene. Vanillic, syringic, p-coumaric, and ferulic acids were found in soluble free, soluble conjugated, and insoluble bound forms in the grain extracts, with ferulic acid as the predominant phenolic acid. The eight soft wheat varieties differed in their antioxidant properties. The tested wheat grain samples exhibited ED(50) values against DPPH(*) of 23-27 mg of grain equiv/mL, ORAC of 32.9-48 micromol of Trolox equiv (TE)/g, and ABTS(*)(+) scavenging capacity of 14.3-17.6 micromol of TE/g. These data suggest the possibility of producing soft wheat varieties rich in selected health beneficial factors for optimum human nutrition though breeding programs.     

Anthocyanins, flavonols, and free radical scavenging activity of Chinese bayberry (Myrica rubra) extracts and their color properties and stability

Characterization of anthocyanins and flavonols and radical scavenging activity assays of extracts from four Chinese bayberry (Myrica rubra) varieties with different fruit colors were carried out. One dominant anthocyanin and three major flavonols were isolated by HPLC, and cyanidin-3-O-glucoside and two of three flavonols, myricetin and quercetin-3-O-rutinoside, were identified by cochromatography with authentic standards. Both DPPH* and ABTS*(+) cation assays indicated that the black varieties (Biji and Hunan) demonstrated much higher radical scavenging activities than the pink (Fenhong) and yellow (Shuijing) varieties, which may be attributed to much higher levels of anthocyanins, flavonoids, and total phenolics in the black varieties. Biji and Hunan had 6.49 and 6.52 mM Trolox equivalent antioxidant capacity (TEAC) per 100 g of fresh weight, whereas the pink (Fenhong) and yellow (Shuijing) bayberries had 1.32 and 1.31 mM TEAC/100 g. Different fruit color was reflected by the surface color and pigment extract color. Color stability of the pigment was dependent on pH, and the pigment was more stable at low pH (pH approximately 1.5). The lightness (L) increased while the chroma (C value) decreased with increase of pH until pH 5, but higher pH caused a small decrease for L and an increase for C.     

Inhibitory effects of muscadine anthocyanins on α-glucosidase and pancreatic lipase activities

Inhibitory effects of the Noble muscadine grape extracts and the representative phytochemicals for anthocyanins (i.e., cyanidin and cyanidin-3,5-diglucoside) on two enzymes, that is, α-glucosidase and pancreatic lipase, were investigated regarding their antidiabetic activities. The study demonstrated that the anthocyanin extracts and the selected chemicals obeyed the competitive mode against the enzymes. The methanolic extracts of whole fruit and skin of the muscadine showed inhibitory activities against the α-glucosidase with their IC(50) values at 1.50 and 2.73 mg/mL, and those against the lipase at 16.90 and 11.15 mg/mL, respectively, which indicated that the muscadine extracts possessed strong antidiabetic activities. Particularly, the ethyl acetate (EtoAc) extract and the butanol (BuOH) extract exhibited much higher inhibitory activities against both enzymes than the CHCl(3) and water extracts, while the majority of anthocyanins existed in the BuOH fractions. Moreover, cyanidin exhibited a much stronger antidiabetic activity than cyanidin-3,5-diglucoside, suggesting that anthocyanins may have higher inhibitory activities after being digested. Further chromatographic analysis by high-performance liquid chromatography-mass spectrometry identified five individual anthocyanins, including cyanidin, delphinidin, petunidin, peonidin, and malvidin glycosides.     

Phytochemical quantification and total antioxidant capacities of emmer (Triticum dicoccon Schrank) and einkorn (Triticum monococcum L.) wheat landraces

In this study, samples of 18 ancient wheat (12 emmer, 6 einkorn) and 2 bread wheat varieties grown in different regions of Turkey were examined for their total phenolics and flavonoids, phenolic acids, lutein, total yellow pigment, and total radical scavenging capacities against ABTS cation. Results showed that health beneficial phytochemicals and total antioxidant capacities were generally significantly different in emmer and einkorn wheat groups. Remarkably higher total antioxidant activity (18.31 +/- 1.31 micromol Trolox equiv/g), total phenolics (6.33 +/- 0.98 micromol gallic acid equiv/g), ferulic acid (662.95 +/- 61.07 microg/g), and flavonoids (1.61 +/- 0.34 micromol catechin equiv/g) content were detected in emmer wheat samples (n = 12), suggesting that they may have high potential for utilization as a novel grain, rich in natural antioxidants. In addition, quite high levels of lutein (7.33 +/- 2.43 microg/g) of einkorn samples (n = 6) hold the potential of developing high-lutein bakery products to considerably raise the dietary intake of carotenoids. These findings for ancient wheat varieties are considered to be very useful in breeding programs for selecting and breeding wheat varieties for higher concentration and better composition of health-beneficial phytochemicals.     

Determination of free flavan-3-ol content in barley (Hordeum vulgare L.) air-classified flours: comparative study of HPLC-DAD/MS and spectrophotometric determinations

The determination of free flavan-3-ol compounds in barley flours (cv. Gotic) and two resulting milling fractions (fine fraction 57% and coarse fraction 43%, w/w) obtained by air classification of dehulled grain is herein described. The determinations were carried out using reversed phase high-performance liquid chromatography coupled with both diode array detection and ESI-MS compared with conventional spectrophotometric determinations (total phenolic compounds by the Folin-Ciocalteu method and free radical scavenging activity with the DPPH assay). Significant correlations among the HPLC quantification, the spectrophotometric data, and the antioxidant capacity of extracts were revealed by Pearson's analysis. Nine flavan-3-ols were identified by HPLC-MS. Catechins and their derivatives were found to make a substantial contribution to the antioxidant power of extracts. The coarse fraction showed larger concentrations of flavan-3-ols (221%) with respect to the fine fraction. This was confirmed by the antioxidant activity of the analyzed flours. The coarse fraction showed the greatest antioxidant activity (1200.1 +/- 66.2 micromol of Trolox equiv/100 g of flour) with respect to whole meal and fine fraction (1025.9 +/- 18.3 and 761.7 +/- 55.3 micromol of Trolox equiv/100 g of flour, respectively).     

Vitamin C equivalent antioxidant capacity (VCEAC) of phenolic phytochemicals

To express the antioxidant capacity of plant foods in a more familiar and easily understood manner (equivalent to vitamin C mg/100 g), two stable radical species, ABTS(*)(-) and DPPH(*), commonly used for antioxidant activity measurements, were employed independently to evaluate their efficacies using apple polyphenolic extracts and seven polyphenolic standards including synthetic Trolox. Their antioxidant activities were expressed as vitamin C equivalent antioxidant capacity (VCEAC) in mg/100 g apple or mg/100 mL of the reference chemical compounds in 10 and 30 min using the ABTS(*)(-) and DPPH(*) scavenging assays, respectively. The antioxidant capacity of Gala apples and seven phenolic standards, determined by both ABTS(*)(-) and DPPH(*) scavenging assays, showed a dose-response of the first-order. Fresh Gala apples had a VCEAC of 205.4 +/- 5.6 mg/100 g using the ABTS assay, and the relative VCEACs of phenolic standards were as follows: gallic acid > quercetin > epicatechin > catechin > vitamin C > rutin > chlorogenic acid > Trolox. With the DPPH radical assay, the VCEAC of fresh Gala apples was 136.0 +/- 6.6 mg/100 g, and the relative VCEACs of seven phenolic standards were, in decreasing order, as follows: gallic acid > quercetin > epicatechin > catechin > or = vitamin C > Trolox > rutin > chlorogenic acid. Because the ABTS assay can be used in both organic and aqueous solvent systems, employs a specific absorbance at a wavelength remote from the visible region, and requires a short reaction time, it is a more desirable method than the DPPH assay. Therefore, it is recommended that antioxidant capacity be expressed as vitamin C mg/100 g equivalent (VCEAC) using the ABTS assay.     

Chemical compositions, antioxidant capacities, and antiproliferative activities of selected fruit seed flours

Seed flours from black raspberry, red raspberry, blueberry, cranberry, pinot noir grape, and chardonnay grape were examined for their total fat content, fatty acid composition, total phenolic content (TPC), total anthocyanin content (TAC), radical scavenging capacities against the peroxyl (ORAC) and stable DPPH radicals, chelating capacity against Fe(2+), and antiproliferative activities using the HT-29 colon cancer cell line. Significant levels of fat were detected in the fruit seed flours and their fatty acid profiles may differ from those of the respective seed oils. Cranberry seed flour had the highest level of alpha-linolenic acid (30.9 g/100 g fat) and the lowest ratio of n-6/n-3 fatty acids (1.2/1). The ORAC value of the chardonnay seed flour was 1076.4 Trolox equivalents mumol/g flour, and its TPC was 186.3 mg gallic acid equivalents/g flour. These values were 3-12 times higher than the other tested fruit seed flours. Furthermore, the ORAC value was significantly correlated to the TPC under the experimental conditions (P < 0.05). These fruit seed flours also differed in their TAC values and Fe(2+)-chelating capacities. In addition, black raspberry, cranberry, and chardonnay grape seed flour extracts were evaluated for their antiproliferative effects using HT-29 colon cancer cells. All three tested seed flour extracts significant inhibited HT-29 cell proliferation. The data from this study suggest the potential of developing the value-added use of these fruit seed flours as dietary sources of natural antioxidants and antiproliferative agents for optimal human health.     

Radical-scavenging activities of citrus essential oils and their components: detection using 1,1-diphenyl-2-picrylhydrazyl

Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).     

High-amylose corn exhibits better antioxidant activity than typical and waxy genotypes

The consumption of fruits, vegetables, and whole grains rich in antioxidative phytochemicals is associated with a reduced risk of chronic diseases such as cancer, coronary heart disease, diabetes, Alzheimer's disease, cataract, and aged-related functional decline. For example, phenolic acids are among the main antioxidative phytochemicals in grains that have been shown to be beneficial to human health. Corn (Zea mays L.) is a major staple food in several parts of the world; thus, the antioxidant activity of several corn types was evaluated. The 2,2-Diphenyl-1-picryhydrazyl free radical (DPPH*) scavenging activity, total phenolic content (TPC), antioxidant capacity of lipid-soluble substances (ACL), oxygen radical absorbance capacity (ORAC), and phenolic acid compositions of typical and mutant genotypes (typical-1, waxy, typical-2, and high-amylose) were investigated. The DPPH* scavenging activity at 60 min was 34.39-44.51% in methanol extracts and 60.41-67.26% in HCl/methanol (1/99, v/v) extracts of corn. The DPPH* scavenging activity of alkaline hydrolysates of corn ranged from 48.63 to 64.85%. The TPC ranged from 0.67 to 1.02 g and from 0.91 to 2.15 g of ferulic acid equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The TPC of alkaline hydrolysates ranged from 2.74 to 6.27 g of ferulic acid equiv/kg of corn. The ACL values were 0.41-0.80 and 0.84-1.59 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The ORAC values were 10.57-12.47 and 18.76-24.92 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. ORAC values of alkaline hydrolysates ranged from 42.85 to 68.31 g of Trolox equiv/kg of corn. The composition of phenolic acids in alkaline hydrolysates of corn was p-hydroxybenzoic acid (5.08-10.6 mg/kg), vanillic acid (3.25-14.71 mg/kg), caffeic acid (2.32-25.73 mg/kg), syringic acid (12.37-24.48 mg/kg), p-coumaric acid (97.87-211.03 mg/kg), ferulic acid (1552.48-2969.10 mg/kg), and o-coumaric acid (126.53-575.87 mg/kg). Levels of DPPH* scavenging activity, TPC, ACL, and ORAC in HCl/methanol extracts were obviously higher than those present in methanol extracts. There was no significant loss of antioxidant capacity when corn was dried at relatively high temperatures (65 and 93 degrees C) postharvest as compared to drying at ambient temperatures (27 degrees C). Alkaline hydrolysates showed very high TPC, ACL, and ORAC values when compared to methanol and HCl/methanol extracts. High-amylose corn had a better antioxidant capacity than did typical (nonmutant) corn genotypes.     

Phenolic content and antioxidant capacity of muscadine grapes

Fruits of 10 cultivars of muscadine grapes (five bronze skin and five purple skin) grown in southern Georgia were separated into skin, seed, and pulp. Each fruit part and the leaves from the corresponding varieties were extracted for HPLC analysis of major phenolics. Total phenolics were determined colorimetrically using Folin-Ciocalteu reagent. Total anthocyanins were determined according to a pH-differential method, using a UV-visible spectrophotometer. Antioxidant capacity was determined by the Trolox equivalent antioxidant capacity (TEAC) assay. Gallic acid, (+)-catechin, and epicatechin were the major phenolics in seeds, with average values of 6.9, 558.4, and 1299.4 mg/100 g of fresh weight (FW), respectively. In the skins, ellagic acid, myricetin, quercetin, kaempferol, and trans-resveratrol were the major phenolics, with respective average values of 16.5, 8.4, 1.8, 0.6, and 0.1 mg/100 g of FW. Contrary to previous results, ellagic acid and not resveratrol was the major phenolic in muscadine grapes. The HPLC solvent system used coupled with fluorescence detection allowed separation of ellagic acid from resveratrol and detection of resveratrol. Reported here for the first time are the phenolic content and antioxidant capacity of muscadine leaves. Major phenolics in muscadine leaves were myricetin, ellagic acid, kaempferol, quercetin, and gallic acid, with average concentrations of 157.6, 66.7, 8.9, 9.8, and 8.6, respectively. Average total phenolics were 2178.8, 374.6, 23.8, and 351.6 mg/g gallic acid equivalent in seed, skin, pulp, and leaves, respectively. Total anthocyanin contents were 2.1 and 132.1 mg/100 g of FW in the skins of bronze and purple grapes, respectively, and 4.3 and 4.6 mg/100 g of FW in seeds and pulps, in that order. Antioxidant capacity values were, on average, 2.4, 12.8, 281.3, and 236.1 microM TEAC/g of FW for pulps, skins, seeds, and leaves, respectively.     

Commercial dietary ingredients from Vitis vinifera L. leaves and grape skins: antioxidant and chemical characterization

This paper reports an attempt to functionally and chemically characterize commercial ingredients from Vitis vinifera L. grape skins, grape pomace, and leaves, which are used in the formulation of dietary antioxidant supplements. The antioxidant capacity of these ingredients was assessed for the first time by the oxygen radical absorbance capacity (ORAC) methodology. Ingredients from grape skins and pomace (n = 17) showed ORAC values from 1.38 to 21.4 mumol Trolox equivalents/mg whereas ingredients from leaves (n = 4) showed ORAC values from 1.52 to 2.55 mumol Trolox equivalents/mg. The high-performance liquid chromatography-diode array detection/electrospray ionization-mass sprectrometry analysis of anthocyanins and flavonols revealed the authenticity of the ingredients as derived from V. vinifera L. and confirmed large differences in their phenolic content and distribution. A progressive decline in both antioxidant capacity and total anthocyanin content of a grape skin ingredient (43 and 40% decrease, respectively) was observed over a 60 day storage period (45 degrees C and 75% relative humidity), demonstrating its poor stability under these conditions.     

Comparison of antioxidant activity, anthocyanins, carotenoids, and phenolics of three native fresh and sun-dried date (Phoenix dactylifera L.) varieties grown in Oman

Fresh and sun-dried dates of three native varieties from Oman, namely, Fard, Khasab, and Khalas, were examined for their antioxidant activity and total contents of anthocyanins, carotenoids, and phenolics, as well as free and bound phenolic acids. All results are expressed as mean value +/- standard deviation (n = 3) on a fresh weight basis. Fresh date varieties were found to be a good source of antioxidants (11687-20604 micromol of Trolox equiv/g), total contents of anthocyanins (0.24-1.52 mg of cyanidin 3-glucoside equiv/100 g), carotenoids (1.31-3.03 mg/100 g), phenolics (134-280 mg of ferulic acid equiv/100 g), free phenolic acids (2.61-12.27 mg/100 g), and bound phenolic acids (6.84-30.25 mg/100 g). A significant (p < 0.05) amount of antioxidants and carotenoids was lost after sun-drying of dates, whereas the total content of phenolics and free and bound phenolic acids increased significantly (p < 0.05). Anthocyanins were detected only in fresh dates. Date varieties had different levels and patterns of phenolic acids. Four free phenolic acids (protocatechuic acid, vanillic acid, syringic acid, and ferulic acid) and nine bound phenolic acids (gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, and o-coumaric acid) were tentatively identified. Of the date varieties studied, Khalas, which is considered to be premium quality, had higher antioxidant activity, total carotenoids, and bound phenolic acids than other varieties. These results suggest that all date varieties serve as a good source of natural antioxidants and could potentially be considered as a functional food or functional food ingredient, although some of their antioxidant constituents are lost during sun-drying.     

Antioxidant activity of uruguayan propolis. In vitro and cellular assays

The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than those of other natural products (8000 μmol Trolox equiv/g propolis). ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteu method) and UV absorption. Total polyphenol content (150 mg gallic acid equiv/g propolis) and flavonoids (45 mg quercetin equiv/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis. Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low-density lipoprotein lipoperoxidation and tyrosine nitration. In addition, Uruguayan propolis was found to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase, suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.     

Nutritional study of copper and zinc in grapes and commercial grape juices from Spain

This paper presents the levels of copper and zinc determined in a total of 66 samples of the most widely consumed varieties of white and red grapes in Spain, as well as those of 60 samples of grape juice (39 from white varieties and 21 from red ones) chosen from the main commercial brands in the country. Atomic absorption spectroscopy was used as analytical technique, with electrothermal atomization after digestion of the sample with HNO(3)-H(2)O(2) for grapes and with HNO(3) for grape juice. The mean Zn contents obtained (0.0462 mg/100 g in grapes and 0.0460 mg/100 mL in grape juice) are lower than those provided by most of the more commonly used food composition tables. The mean Cu contents were 0.0515 mg/100 g in grapes and 0.0063 mg/100 mL in grape juice. On the basis of these data and the official data on consumption of grapes and grape juice in Spain, the contribution of both products to the recommended daily intake of zinc (15 and 12 mg/day for healthy adult men and women, respectively) is estimated to be approximately 0.1%, whereas for Cu, this supply represents rather more than 0.25% of the established ESADDI (1.5-3 mg/day in adults). The growing popularity of these products in recent years, on the basis of its nutritional properties and beneficial effects, requires additional data, and the present findings are of potential use to food composition tables.     

Anthocyanin and proanthocyanidin content in selected white and red wines. Oxygen radical absorbance capacity comparison with nontraditional wines obtained from highbush blueberry

Antioxidant capacity, as measured by oxygen radical absorbance capacity (ORAC(PE)), total phenolic, total and individual anthocyanins, and proanthocyanidin fraction contents were evaluated in red and white wines from grapes. A comparison in terms of antioxidant capacity is made with nontraditional wines made from highbush blueberry. Blueberries are among fruits that are best recognized for their potential health benefits. In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 +/- 96.06 mg/L) than that in white wines (8.75 +/- 4.53 mg/L). A relative high correlation in red wines was found between ORAC(PE) values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05). In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponds to an intake of 2.04 +/- 0.81 mmol of TE, 0.47 +/- 0.15 mmol of TE, and 2.42 +/- 0.88 mmol of TE of ORAC(PE)/day, respectively.     

Isoflavone composition and antioxidant capacity of modified-lipoxygenase soybeans grown in Maryland

Maryland-grown soybean lines modified for low lipoxygenase-1 (LOX-1) content and a traditional nonmodified cultivar were analyzed for fatty acid composition, total phenolic content (TPC), isoflavone composition, relative DPPH? scavenging capacity (RDSC), and hydroxyl radical scavenging capacity (HOSC). Soybean lines included black, brown, and yellow soybeans. TPC of all soybean lines ranged from 2.84 to 4.74 mg gallic acid equiv (GAE)/g flour. Total isoflavones were between 2.78 and 8.66 μmol/g flour. RDSC of all lines was between 0.48 and 14.62 μmol Trolox equiv (TE)/g flour, and HOSC ranged from 53.57 to 135.52 μmol TE/g flour. Some modified-LOX genotypes demonstrated antioxidant capacity and/or isoflavone content similar to or higher than those of the nonmodified cultivar (P < 0.05). Black soybeans demonstrated higher TPC and RDSC than most yellow soybean lines, although they did not have higher isoflavone content. The results demonstrate that modification of the LOX trait did not necessarily alter the antioxidant capacity or chemical composition of the experimental soybean lines when compared with a nonmodified cultivar. These soybean lines may be studied further for nutraceutical properties and use in functional foods.