Anthocyanins in blue berries of Vaccinium padifolium

Twenty anthocyanins were isolated from the extract of the edible blue berries of Vaccinium padifolium (Uveira) by a combination of chromatographic techniques. Mainly on the basis of nuclear magnetic resonance techniques (1H, COSY, TOCSY, HSQC, HMBC, SEFT) they were identified as the 3-O-beta-glucopyranosides, 3-O-beta-galactopyranosides, 3-O-beta-arabinopyranosides and 3-O-sambubiosides (2'-O-beta-xylopyranosyl-O-beta-glucopyranosides) of delphinidin, cyanidin, petunidin,malvidin and peonidin. Anthocyanidin disaccharides have not been identified in the genus Vaccinium previously, and the 3-sambubiosides of peonidin, petunidin and malvidin are novel compounds.Fundação para a Ciência e Tecnologi

Characterization of a Natural, Stable, Reversible and Colourful Anthocyanidin Network from Sphagnum Moss Based Mainly on the Yellow Trans‐Chalcone and Red Flavylium Cation Forms

Anthocyanins with various functions in nature are one of the most important sources of colours in plants. They are based on anthocyanidins or 3-deoxyanthocyanidins having in common a C15-skeleton and are unique in terms of how each anthocyanidin is involved in a network of equilibria between different forms exhibiting their own properties including colour. Sphagnorubin C (1) isolated from the cell wall of peat moss (Sphagnum sp.) was in fairly acidic and neutral dimethyl sulfoxide characterized by nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) absorption techniques. At equilibrium, the network of 1 behaved as a two–component colour system involving the reddish flavylium cationic and the yellow trans–chalcone forms. The additional D- and E-rings connected to the common C15-skeleton extend the π-conjugation within the molecule and provide both bathochromic shifts in the absorption spectra of the various forms as well as a low isomerization barrier between the cis- and trans-chalcone forms. The hemiketal and cis-chalcone forms were thus not observed experimentally by NMR due to their short lives. The stable, reversible network of 1 with good colour contrast between its two components has previously not been reported for other natural anthocyanins and might thus have potential in future photochromic systems. This is the first full structural characterization of any naturally occurring anthocyanin chalcone form.publishedVersio

Colour and stability of pure anthocyanins influenced by pH including the alkaline region

This study on anthocyanin colour variation (intensity, lambda max, absorptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p- coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lambda max absorption of petanin after 5 days at pH 8.1 at 10ºC was similar or higher than the corresponding absorptions of the fresh solutions of cy3glc at any pH. The use of anthocyanins like petanin as food colorants in slightly alkaline products (bakery, milk, egg, etc.) should therefore be considered at least in products with limited storage time kept in a refrigerator.Fundação para a Ciência e Tecnologi

Anthocyanin trisaccharides in blue berries of Vaccinium padifolium

Delphinidin 3-O-alfa-rhamnoside, malvidin 3-O-(6''-O-alfa-rhamnopyranosyl-beta-glucopyranoside) and the 3-O-(6''-O-alfa-rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of cyanidin, petunidin and peonidin were isolated by various chromatographic techniques from the edible berries of Vaccinium padifolium. Their complete structures were elucidated mainly by one- and two-dimensional nuclear magnetic resonance spectroscopy. Together they account for 7% of the anthocyanin content in this species. No anthocyanidin 3-triglycoside, 3-rutinoside or 3-rhamnoside had previously been found in the genus Vaccinium. The 3-O-(6''-O-alfa- rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of petunidin and peonidin are novel compounds.Fundação para a Ciência e Tecnologi

Isolation and Identification of Flavonoids Found in Zostera marina Collected in Norwegian Coastal Waters

In extracts of the seagrass Zostera marina, collected in coastal waters of West-Norway, fourteen different flavones and high amounts of rosmarinic acid were identified. Five of the flavones were found to be sulphated, among these were luteolin 7,3'-disulphate and chrysoeriol 7-sulphate structures previously not published with complete NMR assignments. Luteolin 7-O-β-(6''-malonyl) glucoside, and two other malonylated flavone compounds occurring in trace amounts, were identified for the first time in Z. marina. The sulphated flavones were fairly stable in slightly acidified (0.1% trifluoroacetic acid) extracts stored for months, however, under more acidic conditions (0.5% trifluoroacetic acid in the extracts) they were susceptible to undergo hydrolyses. When the solvents of purified fractions were removed by rotary evaporation, the sulphated flavones quickly decomposed to their corresponding aglycones due to the increased acid concentrations.publishedVersio

Polyacylated anthocyanins from Hebe

Four acylated anthocyanins were isolated from flowers of Hebe spp. On the basis of LC-MS (Liquid Chromatography - Mass Spectrometry) and NMR (Nuclear Magnetic Resonance) techniques, they were identified as (1) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (2) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (3) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside], and (4) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside]. Pigments 2 and 4 are novel compounds.Fundação para a Ciência e Tecnologi

Anthocyanin Profile and Antioxidant Property of Anti-asthma Flowers of Cordyline terminalis (L.) Kunth (Agavaceae)

Cordyline terminalis flower is traditionally used to treat asthma and the purple color of the flower is suggestive of anthocyanins. The purpose of this study was to characterize and determine the antioxidant property of anthocyanins from C. terminalis purple flowers. Five anthocyanins, cyanidin 3,5-di-O-β-glucopyranoside (2.6 ± 0.2 mg/g fr. wt) (1), peonidin 3,5-di-O-β-glucopyranoside (2.8 ± 0.3 mg/g fr. wt) (2), cyanidin 3-O-β-(6″-O-E-p-caffeoylglucopyranoside)-5-O-β-glucopyranoside (3.2 ± 0.2 mg/g fr. wt) (3), cyanidin 3-O-β-(6″-O-E-p-coumaroylglucopyranoside)-5-O-β-glucopyranoside (6.2 ± 0.4 mg/g fr. wt) (4), and peonidin 3-O-β-(6″-O-E-p-coumaroylglucopyranoside)-5-O-β-glucopyranoside (9.8 ± 0.2 mg/g fr. wt) (5), were isolated from the flowers of C. terminalis by a combination of chromatographic techniques. Their structures were established by UV-visible, NMR, and ESI-MS. The extract exhibited appreciable antioxidant activity (IC50 ± SD = 13.1 ± 0.8 μg/mL) against quercetin (IC50 ± SD = 4.5 ± 0.4 μg/mL) compared to the individual anthocyanins (IC50 ± SD = 13.8 ± 0.5 to 16.4 ± 0.7 μg/mL) when measured using the 2,2-diphenyl-1-picryl-hydrazyl method. Cordyline terminalis flowers extract may be justified for use and standardization as herbal remedy for asthma.publishedVersio

Acylated Flavone O-Glucuronides from the Aerial Parts of Nepeta curviflora

Nepeta curviflora Boiss. (Syrian catnip) is native to the Middle East. This medicinal plant is commonly used against nervous disorders, rheumatic pains, and high blood pressure. Herbal infusions prepared from various Nepeta spp. are extensively consumed as functional food. However, limited information has been known about the phenolic constituents of Syrian catnip. In this study, two acylated flavone 7-O-glucuronides, apigenin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (1) and luteolin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (2), along with the known phenolic compounds rosmarinic acid, caffeic acid, apigenin, and apigenin 7-O-β-glucopyranoside were isolated from the aerial parts of N. curviflora. The characterizations of these compounds were based on high-resolution mass spectrometry, UV, and extensive use of multidimensional NMR spectroscopy. The new compounds (1 and 2) were identified in the unmodified state and as dimethylesters.publishedVersio

Anthocyanin-rich extract decreases indices of lipid peroxidation and DNA damage in vitamin E-depleted rats

Anthocyanins are secondary plant metabolites responsible for the blue, purple, and red color of many plant tissues. The phenolic structure of anthocyanins conveys marked antioxidant activity in model systems via donation of electrons or hydrogen atoms from hydroxyl moieties to free radicals. Dietary intakes of anthocyanins may exceed 200 mg/day, however, little is known about their antioxidant potency in vivo. Consequently, the aim of this study was to establish whether anthocyanins could act as putative antioxidant micronutrients. Rats were maintained on vitamin E-deficient diets for 12 weeks in order to enhance susceptibility to oxidative damage and then repleted with rations containing a highly purified anthocyanin-rich extract at a concentration of 1 g/kg diet. The extract consisted of the 3-glucopyranoside forms of delphinidin, cyanidin, petunidin, peonidin, and malvidin. Consumption of the anthocyanin repleted diet significantly improved (p < 0.01) plasma antioxidant capacity and decreased (p < 0.001) the vitamin E deficiency-enhanced hydroperoxides and 8-Oxo-deoxyguanosine concentrations in liver. These compounds are indices of lipid peroxidation and DNA damage, respectively. Dietary consumption of anthocyanin-rich foods may contribute to overall antioxidant status, particularly in areas of habitually low vitamin E intake.Fundação para Ciência e Tecnologi

Nutraceutical characterization of anthocyanin-rich fruits produced by «Sun Black» tomato line

Tomato (Solanum lycopersicum L.) is one of the most cultivated vegetable in the world and it represents a large source of bioactive compounds, including carotenoids and polyphenols (phenolic acids and flavonoids). However, the concentration of flavonoids in tomato is considered sub-optimal, particularly because anthocyanins are not generally present. Therefore, this crop has been the object of an intense metabolic engineering in order to obtain anthocyanin-enriched tomatoes by using either breeding or transgenic strategies. Some wild tomato species, such as S. chilense and S. cheesmaniae, biosynthesize anthocyanins in the fruit sub-epidermal tissue, and some alleles from those genotypes have been introgressed into a new developed purple tomato line, called “Sun Black” (SB). It is a tomato line with a purple skin color, both in green and in red fruit stages, due to the biosynthesis of anthocyanins in the peel, and a normal red color pulp, with a taste just like a traditional tomato. SB is the result of a breeding programme and it is not a genetically modified (GM) product. We report the chemical characterization and structure elucidation of the attractive anthocyanins found in the peel of SB tomato, as well as other bioactive compounds (carotenoids, polyphenols, vitamin C) of the whole fruit. Using one- and two-dimensional NMR experiments, the two main anthocyanins were identified to be petunidin 3-O-[6″-O-(4‴-O-E-p-coumaroyl-α-rhamnopyranosyl) -β-glucopyranoside]-5-O-β-glucopyranoside (petanin) and malvidin 3-O-[6″-O-(4‴-O-E-p-coumaroyl-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside (negretein). The total anthocyanins in the whole ripe fruit was 1.2 mg/g dry weight (DW); 7.1 mg/100 g fresh weight (FW). Chlorogenic acid (the most abundant phenolic acid) was 0.6 mg/g DW; 3.7 mg/100 g FW. The main flavonol, rutin was 0.8 mg/g DW; 5 mg/100 g FW. The total carotenoid content was 211.3 μg/g DW; 1,268 μg/100 g FW. The total phenolic content was 8.6 mg/g DW; 52.2 mg/100 g FW. The vitamin C content was 37.3 mg/100 g FW. The antioxidant activities as measured by the TEAC and ORAC assays were 31.6 and 140.3 μmol TE/g DW, respectively (193 and 855.8 μmol TE/100 g FW, respectively). The results show the unique features of this new tomato genotype with nutraceutical properties.publishedVersio