Quantification of anthocyanins in commercial black currant juices by simple high-performance liquid chromatography. Investigation of their pH stability and antioxidative potency

Quantitative determinations of the four black currant anthocyanins, cyanidin 3-O-beta-glucoside, cyanidin 3-O-beta-rutinoside, delphinidin 3-O-beta-glucoside, and delphinidin 3-O-beta-rutinoside, were achieved in black currant juices by a rapid and sensitive high-performance liquid chromatographic (HPLC) method. The method was validated, and quantification of anthocyanins in 13 commercially available black currant beverages was demonstrated. To optimize the handling of anthocyanin-containing samples, the pH-dependent stability of the anthocyanins was investigated. Four anthocyanins were incubated for 24 h in aqueous solutions at 13 different pH levels between 0.6 and 5.2, after which the samples were analyzed by HPLC. More than 90% of each anthocyanin remained intact up to pH 3.3. At pH 3.8 a local minimum in stability was detected, and at pH >4.5 the stability rapidly decreased. The antioxidant capacity of all 13 black currant juices was investigated by TEAC and FRAP, and the antioxidant potential of both the anthocyanin and the vitamin C contents in the juices was evaluated. This indicated that <70% of the antioxidant capacity of the juices could be attributed to the anthocyanin content or to vitamin C, signifying that other very potent antioxidants are present in commercial black currant juices.     

Effect of clarification techniques and rat intestinal extract incubation on phenolic composition and antioxidant activity of black currant juice

This study examined the phenolic composition and the antioxidant potencies of black currant juices that had been experimentally clarified with acidic proteases and pectinases to retain the phenolics and which had been subjected to rat intestinal mucosa extract incubation to mimic gut cell mediated biotransformation of phenolics. When compared at equimolar levels of 2.5 microM gallic acid equivalents, the black currant juice samples prolonged the induction time of human low-density lipoprotein oxidation in vitro by 2.6-3.6 times, and the order of antioxidant potency of differently clarified black currant juices was centrifuged juice > gelatin silica sol clarified juice > enzymatically clarified juice approximately raw juice. No immediate relationship between the, almost similar, phenolic profiles of the juice samples and their relative antioxidant activities could be established. Incubation of juices with a rat small intestine cell extract for 19 h promoted significant decreases in the contents of the anthocyanin 3-O-beta-glucosides (cyanidin 3-O-beta-glucoside and delphinidin 3-O-beta-glucoside), but did not affect the anthocyanin 3-O-beta-rutinosides (cyanidin 3-O-beta-rutinoside and delphinidin 3-O-beta-rutinoside) of the black currant juice. Black currant juice samples subjected to such intestinal cell extract incubation had approximately 30% decreased antioxidant capacity. Incubation of juices with the rat small intestine cell extracts at neutral pH appeared to decrease the levels of delphinidin glucosides more than the levels of cyanidin glucosides. The results provide an explanation for the predominant detection of anthocyanin rutinosides, and not anthocyanin glucosides, in plasma and urine in in vivo studies and provide important clues to better understand the complex mechanisms affecting dietary phenols in the gut.     

Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms

Four components of black currant anthocyanins (BCA), delphinidin 3-O-beta-rutinoside (D3R), cyanidin 3-O-beta-rutinoside (C3R), delphinidin 3-O-beta-glucoside (D3G), and cyanidin 3-O-beta-glucoside (C3G), were found to be directly absorbed and distributed to the blood and excreted into urine as the glycosylated forms. In a rat study, following oral administration of purified D3R, C3R, and C3G (800 micromol/kg of body weight), the anthocyanins were detected in the plasma and the C(max) values were 580 +/- 410, 850 +/- 120, and 840 +/- 190 nmol/L, respectively, 0.5-2.0 h after administration. In a human study, when a mixture of BCA [6.24 micromol (3.58 mg) consisting of 2.75 micromol (1.68 mg) of D3R, 2.08 micromol (1.24 mg) of C3R, 1.04 micromol (0.488 mg) of D3G, and 0.37 micromol (0.165 mg) of C3G/kg of body weight)] was orally ingested by eight volunteers, D3R, C3R, D3G, and C3G were detected in the plasma and urine. The plasma C(max) values were 73.4 +/- 35.0, 46.3 +/- 22.5, 22.7 +/- 12.4, and 5.0 +/- 3.7 nmol/L, respectively, 1.25-1.75 h after intake, and the cumulative excretion of the four compounds in urine in the period 0-8 h after intake was 0.11 +/- 0.05% of the dose ingested. These results indicate that 3-O-beta-rutinosyl anthocyanins were directly absorbed and distributed to the blood.     

Anthocyanins from black currants (Ribes nigrum L.)

Fifteen anthocyanin structures are reported from an extract of black currant berries (Ribes nigrum L.). These are the 3-O-glucosides and the 3-O-rutinosides of pelargonidin, cyanidin, peonidin, delphinidin, petunidin, and malvidin, cyanidin 3-O-arabinoside, and the 3-O-(6' '-p-coumaroylglucoside)s of cyanidin and delphinidin. The anthocyanins were characterized by means of size exclusion chromatography, high-performance liquid chromatography, UV-visible spectroscopy, and electrospray mass spectrometry. The four main pigments (the 3-O-glucosides and the 3-O-rutinosides of delphinidin and cyanidin) made up >97% of the total anthocyanin content. The minor pigments were enriched from the extract by successive partition against ethyl acetate and by gel fractionation. These chromatographic steps were successfully used to isolate the acylated anthocyanins from the ethyl acetate layer and to separate cyanidin 3-O-arabinoside from the mixture of anthocyanins. The amounts of anthocyanin rutinosides were found to be higher than the amount of the corresponding glucosides for all detected pigments having the same aglycon moiety.     

Anthocyanins in berries of ribes including gooseberry cultivars with a high content of acylated pigments

Consumption of berries from various sources including the genus Ribes has been associated with diverse potential health benefits. The 14 examined cultivars of European gooseberry (R. grossularia L.) contained in various proportions the 3-glucoside (3), 3-rutinoside (4), 3-xyloside (7), 3-O-beta-(6' '-E-caffeoylglucopyranoside) (8), and 3-O-beta-(6' '-E-p-coumaroylglucopyranoside) (10) of cyanidin and the 3-rutinoside (6) and 3-glucoside of peonidin (5). Pigments 3, 4, delphinidin 3-rutinoside (2), delphinidin 3-glucoside (1), and minor amounts of 6, 7, and 10 were found in red flowering currant (R. sanguineum Pursh). Golden currant (R. aureum Pursh) contained 3, 4, and trace amounts of 1, 6, and 7, while alpine currant (R. alpinum L.) contained 3, 4, and trace amounts of 10. The major anthocyanins in two cultivars of jostaberries (R. x nidigrolaria Bauer), 1-4, 8, and 10, reflected that this hybrid contained the major anthocyanins of both parents, black currant and gooseberry. This is the first complete identification of 8 and the ring size of the sugar of 10. Pigment 9 was tentatively identified as cyanidin 3-(6' '-Z-p-coumaroylglucoside). This new pigment occurred in minor amounts (<2%) in all R. grosssularia and R. x nidigrolaria cultivars. No commercially available berries have been reported to contain such high proportions of aromatic acylated anthocyanins as found in the gooseberry cultivars "Sams?", "Hinnom?ki Red", "Taastrup", "Lofthus", and "Glendal", which are in this context the most obvious candidates for consumption, colorant, and breeding programs.     

Anthocyanin-flavanol condensation products from black currant (Ribes nigrum L.)

Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrate from black currant (Ribes nigrum L.). These compounds had UV-vis spectra similar to those of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, but eluted before all previously described anthocyanins on reversed phase HPLC. Mass spectrometric data indicated that they were rutinoside derivatives of novel aglycons 304 amu greater than delphinidin and cyanidin, respectively. The compounds were partly purified by semipreparative HPLC and gave MS and MS2 spectra consistent with anthocyanin rutinosides covalently linked to epigallocatechin or gallocatechin. These compounds are similar in structure to compounds thought to influence color and quality in red wines and strawberry juice products. There was also evidence for the presence of a range of other flavanol-anthocyanin condensation products. The compounds were present at differing levels in juices of 10 black currant varieties, which were roughly correlated to the content of the parent anthocyanins. The flavanol-anthocyanin products were present in polyphenol-enriched concentrates obtained by solid phase extraction, in commercially produced concentrates, and in fresh extracts of black currants. This suggests that the compounds were not artifacts formed during concentration or purification. However, differences in their comparative contents may be related to the lability of the parent anthocyanins during processing. Although present at low levels, the flavanol-anthocyanin products may influence color or quality parameters of black currant juices, and they may confer enhanced stability to the biological activities reported for their anthocyanin parents.     

Delphinidin 3-O-(2-O-beta-D-Glucopyranosyl-alpha-l-arabinopyranoside): a novel anthocyanin identified in Beluga black lentils

A major anthocyanin was isolated from the acidified methanolic extract of Beluga black lentils by XAD7 column chromatography and preparative high-performance liquid chromatography. By means of electrospray ionization mass spectrometry and one- and two-dimensional nuclear magnetic resonance spectroscopy, its structure was determined to be delphinidin 3-O-(2-O-beta-D-glucopyranosyl-alpha-l-arabinopyranoside).     

Anthocyanin profile of Korean cultivated kidney bean (Phaseolus vulgaris L.)

This investigation was conducted to determine the structures and amounts of anthocyanins obtained from seed coats of kidney bean (Phaseolus vulgaris L.) cultivated in Korea. Anthocyanins in the seed coat of kidney bean were extracted with 1% HCl/20% CH(3)OH, and the crude anthocyanin extracts were purified by semipreparative HPLC. Five major anthocyanins were isolated, and their chemical structures were identified by spectroscopic methods (UV-vis, LC/ES-MS, and 1H and 13C NMR). The structures of these five anthocyanins were elucidated as cyanidin 3,5-diglucoside, delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and pelargonidin 3-glucoside. Using RP-HPLC with photodiode array detection, each of the five anthocyanins was separated within 12 min by using a gradient elution. It was proved that the application of RP-HPLC could be an excellent method for determining the composition and contents of anthocyanins in kidney bean. The preponderance of pelargonidin 3-glucoside and delphinidin 3-glucoside are observed in red and black kidney beans, respectively. However, in this study, it is reported for the first time that the contents and composition of anthocyanins in speckled seed depend on the classes of speckle color. The contents of cyanidin 3,5-diglucoside, delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, pelargonidin 3-glucoside, and total anthocyanins in seed coats of 16 kidney beans cultivated in Korea were in the ranges of 0-0.04, 0-2.61, 0-0.12, 0-0.17, 0-0.59 and 0-2.78 mg/g of dried seed coats, respectively.     

Biochemical profiling and chemometric analysis of seventeen UK-grown black currant cultivars

Black currant fruits are recognized as being an important dietary source of health-related compounds, such as anthocyanins and ascorbic acid. In the present study, the biochemical composition (viz., nonstructural carbohydrates, individual anthocyanins, total anthocyanins, total phenolics, and organic acids, including ascorbic acid) from 17 UK-grown black currant cultivars was analyzed. Berry composition was significantly affected by genotype. Nonstructural carbohydrates ranged from 85.09 to 179.92 mg g(-1) on a fresh weight (FW) basis, while concentration for organic acids ranged from 36.56 to 73.35 mg g(-1) FW. Relative concentrations of cyanidin 3-glucoside, cyanidin 3-rutinoside, delphinidin 3-glucoside and delphinidin 3-rutinoside were 3.1-7.9%, 35.4-47.0%, 7.6-12.5% and 36.9-50.9%, respectively. Differences in the biochemical profile among cultivars were emphasized by principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA was able to discriminate between cultivars, especially on the basis of health-related compounds. Initial exploration revealed that individual anthocyanins, total phenolics, and ascorbic acid could be used to characterize and classify different cultivars. HCA showed that the biochemical composition of the different cultivars was related to parentage information.     

Characterization of anthocyanins and pyranoanthocyanins from blood orange [Citrus sinensis (L.) Osbeck] juice

Anthocyanins from blood orange [Citrus sinensis (L.) Osbeck] juices were isolated and purified by means of high-speed countercurrent chromatography and preparative high-performance liquid chromatography. Structures of the pigments were then elucidated by electrospray ionization multiple mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. The major anthocyanins of the juice were characterized as cyanidin 3-glucoside and cyanidin 3-(6"-malonylglucoside). Furthermore, six minor anthocyanins were detected and identified as cyanidin 3,5-diglucoside, delphinidin 3-glucoside, cyanidin 3-sophoroside, delphinidin 3-(6"-malonylglucoside), peonidin 3-(6"-malonylglucoside), and cyanidin 3-(6"-dioxalylglucoside). The occurrence of the latter compound in blood oranges is reported here for the first time, together with full NMR spectroscopic data. Further investigations revealed the presence of four anthocyanin-derived pigments, which are formed through a direct reaction between anthocyanins and hydroxycinnamic acids during prolonged storage of the juice. These novel pyranoanthocyanins were identified as the 4-vinylphenol, 4-vinylcatechol, 4-vinylguaiacol, and 4-vinylsyringol adducts of cyanidin 3-glucoside through comparison of their mass spectrometric and chromatographic properties with those of synthesized reference compounds.     

Influence of vine vigor on grape (Vitis vinifera L. Cv. Pinot Noir) anthocyanins. 2. Anthocyanins and pigmented polymers in wine

The relationships between grapevine (Vitis vinifera) vigor variation and resulting wine anthocyanin concentration and composition and pigmented polymer formation were investigated. The study was conducted in a commercial vineyard consisting of the same clone, rootstock, age, and vineyard management practices. Vine vigor parameters were used to designate vigor zones within two vineyard sites (A and B) to produce research wines (2003 and 2004) and conduct a model extraction experiment (2004 only) to investigate the vine-fruit-wine continuum. Wines and model extracts were analyzed by HPLC and UV-vis spectrophotometry. For the model extractions, there were no differences between sites for pomace weight, whereas juice volume was higher for site A. This was not related to a larger berry size. Site A had a higher anthocyanin concentration (milligrams per liter) in the model extracts than site B specifically for the medium- and low-vigor zones. For anthocyanin composition in the model extraction, site B had a greater proportion of malvidin-3-O-glucoside and less of the remaining anthocyanin glucosides (delphinidin, cyanidin, petunidin, and peonidin) compared to site A. In the wines, there was a vintage effect, with the 2003 wines having a higher anthocyanin concentration (milligrams per liter) than the 2004 wines. This appears to have been primarily due to a greater accumulation of anthocyanins in the fruit. In general, the medium-vigor zone wines had higher anthocyanin concentrations than either the high- or low-vigor zone wines. There was also vintage variation related to anthocyanin composition, with the 2003 wines having a higher proportion of delphinidin and petunidin glucosides and lower malvidin-3-O-glucoside compared to 2004. In both years, there were higher proportions of delphinidin and petunidin glucosides in wines made from low-vigor-zone fruit. Wines made from low-vigor zones showed a greater propensity to form vitisin A as well as pigmented polymers. Low-vigor-zone wines had a approximately 2-fold increase in pigmented polymer concentration (milligrams per liter) over high-vigor-zones wines. There was a strong positive relationship between pigmented polymer concentration, bisulfite bleaching resistant pigments, proanthocyanidin concentration, and color density in wines. Overall, differences found in the wines magnified variation in the fruit.     

Anthocyanin composition in black, blue, pink, purple, and red cereal grains

Anthocyanin pigments from a wide variety of edible and ornamental black, blue, pink, purple, red, and white wheat, barley, corn, rice, and wild rice were identified and quantified to evaluate their potential as natural colorants or functional food ingredients. The total anthocyanin contents varied significantly and exhibited a range of 7-3276 microg/g. Some grains, such as red rice and black rice, contained a limited number of pigments, whereas others, such as blue, pink, purple, and red corns, had complex anthocyanin profiles. Of the 42 anthocyanin compounds observed, 9 were characterized by comparison of the spectroscopic and chromatographic properties with those of authentic standards. The remaining compounds were tentatively identified on the basis of spectroscopic properties and electrospray ionization mass spectra. The most abundant anthocyanins were cyanidin 3-glucoside in black and red rices and in blue, purple, and red corns, pelargonidin 3-glucoside in pink corn, and delphinidin 3-glucoside in blue wheat.     

Absorption and excretion of black currant anthocyanins in humans and watanabe heritable hyperlipidemic rabbits

Anthocyanins are thought to protect against cardiovascular diseases. Watanabe heritable hyperlipidemic (WHHL) rabbits are hypercholesterolemic and used as a model of the development of atherosclerosis. To compare the uptake and excretion of anthocyanins in humans and WHHL rabbits, single-dose black currant anthocyanin studies were performed. Procedures for workup and analyses of urine and plasma samples containing anthocyanins were developed with high recoveries (99 and 81%, respectively) and low limits of quantification (> or =6.6 and > or =1.1 nM, respectively). The excretion and absorption of anthocyanins from black currant juice were found to be within the same order of magnitude in the two species regarding urinary excretion within the first 4 h (rabbits, 0.035%; humans, 0.072%) and t(max) (rabbits, approximately 30 min; humans, approximately 45 min). A food matrix effect was detected in rabbits, resulting in the absorption of a higher proportion of the anthocyanins from black currant juice than from an aqueous citric acid matrix. In humans the absorption and urinary excretion of anthocyanins from black currant juice were found to be proportional with dose and not influenced by the ingestion of a rice cake. In both species a larger proportion of the anthocyanin rutinosides than of the glucosides was absorbed, whereas the structure of the aglycon had no influence on the absorption and excretion. The anthocyanins had no effect in rabbits on the antioxidant capacity of plasma measured as Trolox equivalent antioxidant capacity and ferruc reducing ability of plasma.     

High-performance liquid chromatography with photodiode array detection (HPLC-DAD)/HPLC-mass spectrometry (MS) profiling of anthocyanins from Andean Mashua Tubers (Tropaeolum tuberosum Ruíz and Pavón) and their contribution to the overall antioxidant activity

Mashua (Tropaeolum tuberosum Ruíz and Pavón), an Andean tuber with high antioxidant activity, has sparked interest because of its traditional medicinal use. In this study, we evaluated the anthocyanin composition for three purple mashua genotypes and their contribution to the overall antioxidant activity of the tuber. Mashua anthocyanins, total phenolics, and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) antioxidant activity ranged from 45.5 to 131.9 mg of cyanidin 3-glucoside equivalents/100 g fresh weight (FW), 174.9 to 275.5 mg of gallic acid equivalents/100 g of FW, and 16.2 to 45.7 micromol of Trolox equivalents/g of FW, respectively. The high-performance liquid chromatography with photodiode array detection (HPLC-DAD) and HPLC-electrospray ionization tandem mass spectrometry (ESI/MS-MS) profiles revealed the presence of 11 different anthocyanins. The two major pigments (56.4-73.0% total area range at 520 nm) were identified as delphinidin 3-glucoside-5-acetylrhamnoside and delphinidin 3-sophoroside-5-acetylrhamnoside. Other pigments were delphinidin 3-glucoside-5-rhamnoside, delphinidin 3-sophoroside-5-rhamnoside, delphinidin 3-glucoside, cyanidin 3-sophoroside, and cyanidin 3-sophoroside-5-rhamnoside. Cyanidin 3-glucoside and cyanidin 3-rutinoside were only found in two genotypes, while pelargonidin 3-sophoroside and pelargonidin 3-sophoroside-5-rhamnoside were only found in the third one. Anthocyanins from mashua were the major contributors to the total ABTS values for only one of the three genotypes, suggesting that other phenolics present are playing a major role in the antioxidant power of mashua tubers. Results from this study provide important information for the Nutraceutical and Functional Food Market for the use of mashua anthocyanins not only as a source of natural colorants but also as a source of phytonutrients.     

Saskatoon and wild blueberries have higher anthocyanin contents than other Manitoba berries

Studies have shown that anthocyanins present in berry fruits have some beneficial health effects such as reducing age-associated oxidative stress and possessing anti-inflammatory properties. Therefore, six Manitoba berries (wild blueberry, Saskatoon berry, raspberry, chokecherry, strawberry, and seabuckthorn) were studied for their anthocyanin compositions (mg/100 g) on dry weight basis. Saskatoon berry and wild blueberry showed a high content of total anthocyanins (562.4 and 558.3 mg/100 g, respectively) that were not significantly (P>0.05) different from each other. The corresponding values for other berries: raspberry (365.2 mg/100 g), chokecherry (177.39 mg/100 g), and strawberry (97.5 mg/100 g) were significantly different from each other (P<0.05), and the total anthocyanin content of seabuckthorn was negligible (0.84 mg/100 g). Fifteen major anthocyanins were isolated from Manitoba berries. Saskatoon berry and wild blueberry contained higher amounts of delphinidin 3-glucoside (Dp-3-glc), malvidin 3-glucoside (Mv-3-glc), and malvidin 3-galactoside (Mv-3-gal). Dp-3-glc was 263.8 (mg/100 g) in Saskatoon berry and 84.4 (mg/100 g) in wild blueberry, whereas the corresponding values for Mv-3-glc in these berries were 47.4 and 139.6 (mg/100 g), respectively. Raspberry, strawberry, and chokecherry contained higher amounts of cyanidin 3-glucoside (Cy-3-glc), cyanidin 3-rutinoside (Cy-3-rut), and pelargonidin 3-glucoside (Pg-3-glc). The total anthocyanin content of Manitoba fruits followed the order: Saskatoon berry and blueberry (high anthocyanin berries), raspberry and chokecherry (medium anthocyanin berries), strawberry (low anthocyanin berries), and seabuckthorn (negligible anthocyanin berries). This study demonstrated that Saskatoon berries and wild blueberries have high potential value for fruit growers as well as the food and nutraceutical manufacturers because of their high anthocyanin contents.     

Characterization of anthocyanins from the fruits of baguaçu (Eugenia umbelliflora Berg)

Anthocyanin pigments in the berries of bagua?u (Eugenia umbelliflora Berg), a tropical fruit from Brazil, were extracted with 0.1% HCl in ethanol, and the crude anthocyanin extract was purified by Amberlite XAD-7 open-column chromatography. Six major anthocyanins were isolated by preparative HPLC, and their chemical structures were identified by spectroscopic methods (TLC, UV-vis, MS, and (1)H NMR). Delphinidin 3-O-beta-glucopyranoside, cyanidin 3-O-beta-glucopyranoside, petunidin 3-O-beta-glucopyranoside, pelargonidin 3-O-beta-glucopyranoside, peonidin 3-O-beta-glucopyranoside, and malvidin 3-O-beta-glucopyranoside were identified. On the basis of chromatographic data the total anthocyanin content was 342 mg/100 g of fresh bagua?u berries. Therefore, the concomitant presence of six anthocyanins in a single plant species makes this product promising as a new pigment source.     

Identification of anthocyanins in Rhamnus alaternus L. berries

Anthocyanin composition in berries of Rhamnus alaternus L., a perennial wild shrub typical of the Mediterranean area, was determined for the first time. The pigments were extracted from the berries with 0.1% HCl in methanol and purified using a C-18 solid-phase cartridge. High-performance liquid chromatography diode array detection-mass spectrometry analysis showed that delphinidin 3-O-rutinoside represented about 62.4% of the total pigments. Other anthocyanins were 3-O-rutinoside derivatives of cyanidin (8.4%), petunidin (15.8%), pelargonidin (4.7%), and peonidin and malvidin (8.7%). The concomitant presence of the six most common anthocyanidins suggested that R. alaternus berries, besides being a good pigment source, could also be a useful tool for anthocyanin identification.     

Structures and antioxidant activity of anthocyanins in many accessions of eggplant and its related species

Anthocyanins were detected in extracts from the peels of 123 accessions of eggplant (Solanum melongena) and its related species. Their anthocyanin profiles were classified into four types, including known Japanese eggplant type (type 1) and non-Japanese eggplant type (type 2). Although most of the eggplant accessions had one of the two known profiles, one accession had a novel profile (type 3). Two accessions of related species showed another novel profile (type 4). The major anthocyanins were identified as delphinidin 3-(p-coumaroylrutinoside)-5-glucoside (nasunin) (type 1), delphinidin 3-rutinoside (type 2), delphinidin 3-glucoside (type 3), and petunidin 3-(p-coumaroylrutinoside)-5-glucoside (petunidin 3RGc5G) (type 4). Delphinidin 3-caffeoylrutinoside-5-glucoside (delphinidin 3RGcaf5G) was isolated from the hybrid (F1) plants of a type 1 cultivar and a type 3 germplasm. Among the five purified anthocyanins, delphinidin 3RGcaf5G showed the highest radical-scavenging activities toward both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and linoleic acid radical, followed in order by nasunin and petunidin 3RGc5G.     

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.     

Antioxidant activities and anthocyanin content of fresh fruits of common fig (Ficus carica L.)

Fig fruit has been a typical component in the health-promoting Mediterranean diet for millennia. To study the potential health-promoting constituents of fig fruits, six commercial fig varieties differing in color (black, red, yellow, and green) were analyzed for total polyphenols, total flavonoids, antioxidant capacity, and amount and profile of anthocyanins. Using reversed-phase liquid chromatography (RP-LC), various concentrations of anthocyanins but a similar profile was found in all varieties studied. Hydrolysis revealed cyanidin as the major aglycon. Proton and carbon NMR confirmed cyanidin-3-O-rhamnoglucoside (cyanidin-3-O-rutinoside; C3R) as the main anthocyanin in all fruits. Color appearance of fig extract correlated well with total polyphenols, flavonoids, anthocyanins, and antioxidant capacity. Extracts of darker varieties showed higher contents of phytochemicals compared to lighter colored varieties. Fruit skins contributed most of the above phytochemicals and antioxidant activity compared to the fruit pulp. Antioxidant capacity correlated well with the amounts of polyphenols and anthocyanins (R2 = 0.985 and 0.992, respectively). In the dark-colored Mission and the red Brown-Turkey varieties, the anthocyanin fraction contributed 36 and 28% of the total antioxidant capacity, respectively. C3R contributed 92% of the total antioxidant capacity of the anthocyanin fraction. Fruits of the Mission variety contained the highest levels of polyphenols, flavonoids, and anthocyanins and exhibited the highest antioxidant capacity.