Anthocyanidin glycosides from the flowers of Alstroemeria

Three anthocyanins were isolated from the red flowers of four cultivars of Alstroemeria. Two compounds were novel anthocyanidin glycosides; the 3-rutinoside and 3-monoglucoside of 6-hydroxycyanidin. Cyanidin 3-rutinoside was also present in the petals.     

Acylated anthocyanins from the violet-blue flowers of Orychophragonus violaceus

Three acylated cyanidin 3-sambubioside-5-glucosides (1-3) were isolated from the violet-blue flowers of Orychophragonus violaceus, and their structures were determined by chemical and spectroscopic methods. Two of those acylated anthocyanins (1 and 3) were cyanidin 3-O-[2-O-(2-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-trans-acyl)-beta-D-glucopyranoside]-5-O-(6-O-malonyl-beta-D-glucopyranoside)s, in which the acyl groups were p-coumaric acid for 1, and sinapic acid for 3, respectively. The last anthocyanin 2 was cyanidin 3-O-[2-O-(2-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-trans-feruloyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside. In these flowers, the anthocyanins 2 and 3 were present as dominant pigments, and 1 was obtained in rather small amounts.     

Triacylated cyanidin 3-(3X-glucosylsambubioside)-5-glucosides from the flowers of Malcolmia maritima

Three acylated cyanidin 3-(3(X)-glucosylsambubioside)-5-glucosides (1-3) and one non-acylated cyanidin 3-(3(X)-glucosylsambubioside)-5-glucoside (4) were isolated from the purple-violet or violet flowers and purple stems of Malcolmia maritima (L.) R. Br (the Cruciferae), and their structures were determined by chemical and spectroscopic methods. In the flowers of this plant, pigment 1 was determined to be cyanidin 3-O-[2-O-(2-O-(trans-sinapoyl)-3-O-(beta-D-glucopyranosyl)-beta-D-xylopyranosyl)-6-O-(trans-p-coumaroyl)-beta-D-glucopyranoside]-5-O-[6-O-(malonyl)-(beta-D-glucopyranoside) as a major pigment, and a minor pigment 2 was determined to be the cis-p-coumaroyl isomer of pigment 1. In the stems, pigment 3 was determined to be cyanidin 3-O-[2-O-(2-O-(trans-sinapoyl)-3-O-(beta-D-glucopyranosyl)-beta-D-xylopyranosyl)-6-O-(trans-p-coumaroyl)-beta-d-glucopyranoside]-5-O-(beta-D-glucopyranoside) as a major anthocyanin, and also a non-acylated anthocyanin, cyanidin 3-O-[2-O-(3-O-(beta-D-glucopyranosyl)-beta-D-xylopyranosyl)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside) was determined to be a minor pigment (pigment 4). In this study, it was established that the acylation-enzymes of malonic acid has important roles for the acylation of 5-glucose residues of these anthocyanins in the flower-tissues of M. maritima; however, the similar enzymatic reactions seemed to be inhibited or lacking in the stem-tissues.     

Covalent anthocyanin-flavonol complexes from flowers of chive, Allium schoenoprasum

The structures of eight anthocyanins have been determined in acidified methanolic extract of pale-purple flowers of chive, Allium schoenoprasum. Four of them have been identified as the anthocyanin-flavonol complexes (cyanidin 3-O-beta-glucosideAII) (kaempferol 3-O-(2-O-beta-glucosylFIII-beta-glucosideFII)-7-O-beta-gl ucosiduronic acidFIV) malonateAIII (AII-6-->AIII-1, FIV-2-->AIII-3), 1, (cyanidin 3-O-(3-O-acetyl-beta-glucosideAII) (kaempferol 3-O-(2-O-beta-glucosylFIII-beta-glucosideFII)-7-O-beta-gl ucosiduronic acidFIV) malonateAIII (AII-6-->AIII-1, FIV-2-->AIII-3), 2, and their 7-O-(methyl-O-beta-glucosiduronateFIV) analogous, 3 and 4. Pigments 1 and 2 are the first final identification of covalent complexes between an anthocyanin and a flavonol, while 3 and 4 are formed during the isolation process. The other four anthocyanins (5-8) were found to be the 3-acetylglucoside, 3-glucoside, 3-(6-malonylglucoside) and 3-(3,6-dimalonylglucoside) of cyanidin. The three latter pigments have earlier been identified as the major anthocyanins of the chive stem. The covalent anthocyanin-flavonol complexes show intramolecular association between the anthocyanidin (cyanidin) and flavonol (kaempferol) units, which influence the colour.     

Two triacylated and tetraglucosylated anthocyanins from Ipomoea asarifolia flowers

Two triacylated and tetraglucosylated anthocyanins derived from cyanidin were isolated from the flowers of Ipomoea asarifolia and their structures elucidated using chemical, GC, MS and NMR methods (1H and 13C, TOCSY-1D, DQF-COSY, DIFFNOE and HMBC). These complex pigments were found to consist of cyanidin 3-O-[2-O-(6-O-E-caffeoyl-beta-D-glucopyranosyl)]-[6-O-[4-O-(6-O-E-3,5-dihydroxycinnamoyl-beta-D-glucopyranosyl)-E-caffeoyl]-beta-D-glucopyranosyl]-5-O-beta-D-glucopyranoside and cyanidin 3-O-[2-O-(6-O-E-p-coumaroyl-beta-D-glucopyranosyl)]-[6-O-[4-O-(6-O-E-p-coumaroyl-beta-D-glucopyranosyl)-E-caffeoyl]-beta-D-glucopyranosyl]-5-O-beta-D-glucopyranoside.     

Acylated cyanidin 3-sambubioside-5-glucosides in three garden plants of the Cruciferae

Seven acylated cyanidin 3-sambubioside-5-glucosides were isolated from the flowers of three garden plants in the Cruciferae. Specifically, four pigments were isolated from Lobularia maritima (L.) Desv., together with a known pigment, as well as, three pigments from Lunaria annua L., and two known pigments from Cheiranthus cheiri L. These pigments were determined to be cyanidin 3-O-[2-O-((acyl-II)-(beta-d-xylopyranosyl))-6-O-(acyl-I)-beta-d-glucopyranoside]-5-O-[6-O-(acyl-III)-beta-d-glucopyranoside], in which the acyl-I group is represented by glucosyl-p-coumaric acid, p-coumaric acid and ferulic acid, acyl-II by caffeic acid and ferulic acid, and acyl-III by malonic acid, respectively. The distribution and biosynthesis of acylated cyanidin 3-sambubioside-5-glucosides are discussed according to the variations of acylation and glucosylation at their 3-sambubiose residues.     

Anthocyanins acylated with gallic acid from chenille plant, Acalypha hispida

Three anthocyanins were isolated from the red flowers of chenille plant, Acalypha hispida Burm. (Euphorbiaceae) by a combination of chromatographic techniques. Their structures were elucidated mainly by homo- and heteronuclear nuclear magnetic resonance spectroscopy and electrospray mass spectrometry, and supported with complete assignments of 13C NMR resonances. The novel pigment, cyanidin 3-O-(2"-galloyl-6"-O-alpha-rhamnopyranosyl-beta-galactopyranoside) (5%), contains the disaccharide robinoside. The other anthocyanins were identified as cyanidin 3-O-(2"-galloyl-beta-galactopyranoside) (85%), and cyanidin 3-O-beta-galactopyranoside (5%). Anthocyanins acylated with gallic acid have previously been identified in species from the families Nymphaeaceae and Aceraceae, and tentatively in Abrus precatorius (Leguminosae).     

The identification of flavonoids and the expression of genes of anthocyanin biosynthesis in the chrysanthemum flowers

In order to provide additional information on the coloration of chrysanthemum flowers, the flavonoid composition and the expression of six structural genes involved in anthocyanin pathway in the ray florets of a pink flowering (cv. H5) and two white flowering (cvs. Keikai and Jinba) Chrysanthemum grandiflorum cultivars were examined. HPLCDAD/ESI-MSⁿ analysis showed that cyanidin 3-O-(6″-O-malonylglucoside) and cyanidin 3-O-(3″,6″-O-dimalonylglucoside) were the two major flavonoids presented in H5, while white flowering cultivars contained flavones instead of anthocyanins. Nine flavone derivatives were detected in the three cultivars, the amount of each flavone varied upon cultivars, and seven of these were identified as luteolin 7-O-arabinosylglucuronide, apigenin 7-O-glucoside, luteolin 7-O-malonylglucoside, apigenin 7-O-malonylglucoside, chrysoeriol 7-O-malonylglucoside, acacetin 7-O-rutinoside and acacetin 7-O-malonylglucoside. The two white flowering cultivars showed similar total flavonoid content, which was about two fold higher than that in H5. A high expression of the genes encoding dihydroflavonol 4-reductase and 3-O-glucosyltransferase was detected only in H5 but not in Keikai or Jinba. Chalcone synthase, chalcone isomerase, flavanone 3-hydroxylase, and flavonoid 3′-hydroxylase were expressed in all flowers, suggesting that the lack of anthocyanin in white flowering cultivars cannot be due to any blockage of their expression.     

Acylated anthocyanidin 3-sophoroside-5-glucosides from Ajuga reptans flowers and the corresponding cell cultures

Four anthocyanins from Ajuga reptans flowers and its cell cultures were isolated, and a fifth was also characterized by HPLC-mass spectrometry. By means of chemical and spectroscopic analyses, their structures were identified as delphinidin 3-(p-coumaroyl-feruloyl)sophoroside-5-malonylglucoside, delphinidin 3-(diferuloyl)sophoroside-5-malonylglucoside, and cyanidin 3-(di-p-coumaroyl)sophoroside-5-glucoside, respectively. The other two were tentatively identified as delphinidin 3-(diferuloyl)sophoroside-5-glucoside and cyanidin 3-(feruloyl-p-coumaroyl)sophoroside-5-malonylglucoside. In neutral aqueous solution, the crude extract from A. reptans flower cell cultures and the major anthocyanin cyanidin 3-(di-p-coumaroyl)sophoroside-5-malonylglucoside were more stable than cyanidin 3-glucoside, and also prevented more efficiently peroxidation than did the latter. A. reptans flower cell culture anthocyanins may have a potential as natural colorants for food utilities or other purposes.     

The structure of the major anthocyanin in Arabidopsis thaliana

The major anthocyanin in the leaves and stems of Arabidopsis thaliana has been isolated and shown to be cyanidin 3-O-[2-O(2-O-(sinapoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-p-coumaroyl-beta-D-glucopyranoside] 5-O-[6-O-(malonyl) beta-D-glucopyranoside]. This anthocyanin is a glucosylated version of one of the anthocyanins found in the flowers of the closely related Matthiola incana.     

Anthocyanins from flowers of the orchids Dracula chimaera and D. cordobae

The main anthocyanins from flowers of the orchids Dracula chimaera and D. cordobae were isolated from a purified methanolic extract by preparative HPLC. Their structures were determined to be cyanidin 3-O-(6"-O-malonyl-beta-glucopyranoside), cyanidin 3-O-(6"-O-alpha-rhamnopyranosyl-beta-glucopyranoside), cyanidin 3-O-beta-glucopyranoside, peonidin 3-O-(6"-O-alpha-rhamnopyranosyl-beta-glucopyranoside) and peonidin 3-O-(6"-O-malonyl-beta-glucopyranoside). The structure determinations were mainly based on extensive use of 2D and 1D NMR spectroscopy, UV-vis spectroscopy and MS. The anthocyanin contents of species belonging to the subtribe Pleurothallidinae including genus Dracula Luer (Orchidaceae) have previously not been determined. The high content of anthocyanin rutinosides found in D. chimaera and D. cordobae (78 and 28% of the total anthocyanin content, respectively) differs from previously analysed orchid species, in which glucose is found as the only anthocyanin sugar moiety.     

7-O-Methylated anthocyanidin glycosides from Catharanthus roseus

Anthocyanins were isolated from orange-red flowers of Catharanthus roseus cv 'Equator Deep Apricot', and identified as rosinidin 3-O-[6-O-(alpha-rhamnopyranosyl)-beta-galactopyranoside] (1), and also 7-O-methylcyanidin 3-O-[6-O-(alpha-rhamnopyranosyl)-beta-galactopyranoside] (2) by chemical and spectroscopic methods. Pigment 1 was found to be a major anthocyanin in the flowers of this cultivar. By contrast, the distribution of rosinidin glycosides is very limited in plants, and reported only in the flowers of Primula. Pigment 2 was found in smaller concentrations, but its aglycone, 7-O-methylcyanidin, has been reported only once before, from the fruit of mango.     

A New Acylated Anthocyanin from the Red Flowers of Camellia hongkongensis and Characterization of Anthocyanins in the Section Camellia Species

Twelve anthocyanins (1-12) were isolated from the red flowers of Camellia hongkongensis Seem. by chromatography using open columns. Their structures were elucidated on the basis of spectroscopic analyses, that is, proton-nuclear magnetic resonance, carbon 13-nuclear magnetic resonance, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, high resolution electrospray ionization mass and ultraviolet visible spectroscopies. Out of these anthocyanins, a novel acylated anthocyanin, cyanidin 3-O-(6-O-(Z)-p-coumaroyl)-β-galactopyranoside (6), two known acylated anthocyanins, cyanidin 3-O-(6-O-(E)-p-coumaroyl)-β-galactopyranoside (7) and cyanidin 3-O-(6-O-(E)-caffeoyl)-β-galactopyranoside (8), and three known delphinidin glycosides (10-12) were for the first time isolated from the genus Camellia. Furthermore, pigment components in C. japonica L., C. chekiangoleosa Hu and C. semiserrata Chi were studied.The results indicated that the distribution of anthocyanins was differed among these species. Delphinidin glycoside was only detected in the flowers of C. hongkongensis, which is a special and important species in the section Camellia. Based on the characterization of anthocyanins in the section Camellia species, there is a close relationship among these species,and C. hongkongensis might be an important parent for creating new cultivars with bluish flower color.     

A rationale for the shift in colour towards blue in transgenic carnation flowers expressing the flavonoid 3',5'-hydroxylase gene

Recently marketed genetically modified violet carnations cv. Moondust and Moonshadow (Dianthus caryophyllus) produce a delphinidin type anthocyanin that native carnations cannot produce and this was achieved by heterologous flavonoid 3',5'-hydroxylase gene expression. Since wild type carnations lack a flavonoid 3',5'-hydroxylase gene, they cannot produce delphinidin, and instead accumulate pelargonidin or cyanidin type anthocyanins, such as pelargonidin or cyanidin 3,5-diglucoside-6"-O-4, 6"'-O-1-cyclic-malyl diester. On the other hand, the anthocyanins in the transgenic flowers were revealed to be delphinidin 3,5-diglucoside-6"-O-4, 6"'-O-1-cyclic-malyl diester (main pigment), delphinidin 3,5-diglucoside-6"-malyl ester, and delphinidin 3,5-diglucoside-6",6"'- dimalyl ester. These are delphinidin derivatives analogous to the natural carnation anthocyanins. This observation indicates that carnation anthocyanin biosynthetic enzymes are versatile enough to modify delphinidin. Additionally, the petals contained flavonol and flavone glycosides. Three of them were identified by spectroscopic methods to be kaempferol 3-(6"'-rhamnosyl-2"'-glucosyl-glucoside), kaempferol 3-(6"'-rhamnosyl-2"'-(6-malyl-glucosyl)-glucoside), and apigenin 6-C-glucosyl-7-O-glucoside-6"'-malyl ester. Among these flavonoids, the apigenin derivative exhibited the strongest co-pigment effect. When two equivalents of the apigenin derivative were added to 1 mM of the main pigment (delphinidin 3,5-diglucoside-6"-O-4,6"'-O-1-cyclic-malyl diester) dissolved in pH 5.0 buffer solution, the lambda(max) shifted to a wavelength 28 nm longer. The vacuolar pH of the Moonshadow flower was estimated to be around 5.5 by measuring the pH of petal. We conclude that the following reasons account for the bluish hue of the transgenic carnation flowers: (1). accumulation of the delphinidin type anthocyanins as a result of flavonoid 3',5'-hydroxylase gene expression, (2). the presence of the flavone derivative strong co-pigment, and (3). an estimated relatively high vacuolar pH of 5.5.     

Acylated anthocyanins from the blue-violet flowers of Anemone coronaria

Five polyacylated anthocyanins were isolated from blue-violet flowers of Anemone coronaria 'St. Brigid'. They were identified as delphinidin 3-O-[2-O-(2-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(malonyl)-beta-D-galactopyranoside]-7-O-[6-O-(trans-caffeoyl)-beta-D-glucopyranoside]-3'-O-[beta-D-glucuronopyranoside], and its demalonylated form, delphinidin 3-O-[2-O-(2-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(2-O-tartaryl)malonyl)-beta-D-galactopyranoside]-7-O-[6-O-(trans-caffeoyl)-beta-D-glucopyranoside]-3'-O-[beta-D-glucuronopyranoside], and its cyanidin analog as well as delphinidin 3-O-[2-O-(2-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(2-O-(tartaryl)malonyl)-beta-D-galactopyranoside]-7-O-[6-O-(trans-caffeoyl)-beta-D-glucopyranoside].     

Cyanidin glycosides in flowers of genus Corydalis (Fumariaceae)

Nine taxa of Corydalis were surveyed for their floral anthocyanins. Five cyanidin glycosides: cyanidin 3-glucoside, cyanidin 3-sambubioside, cyanidin 3-rutinoside, cyanidin 3-(2^G-xylosylrutinoside) and cyanidin 3-(2^G-xylosylrutinoside)-7-glucoside were isolated from these taxa and identified by chemical and spectroscopic techniques. A novel anthocyanin was found in the flowers of Corydalis elata and Corydalis flexuosa cultivars, and identified to be cyanidin 3-(2^G-xylosylrutinoside)-7-glucoside. Two anthocyanins, cyanidin 3-sambubioside and cyanidin 3-(2^G-xylosylrutinoside), were also found for the first time in Corydalis flowers. Furthermore, the major anthocyanin constituent of the flowers was cyanidin 3-sambubioside in the outer petals of Corydalis ambigua and Corydalis lineariloba, and cyanidin 3-rutinoside in those of Corydalis decumbens, Corydalis curvicalcarata and Corydalis speciosa. Similarly, Corydalis incisa contained cyanidin 3-(2^G-xylosylrutinoside), and C. flexuosa ‘China Blue’ and ‘Blue Panda’, and C. elata contained the most complex structural pigment, cyanidin 3-(2^G-xylosylrutinoside)-7-glucoside, as their dominant anthocyanin in their outer petals. According to the results of anthocyanin analyses, these nine plants were classified into four groups: groups A (three taxa), B (two taxa), C (one taxa) and D (three taxa). On the other hand, the anthocyanin constituent of their inner petals was composed of cyanidin 3-rutinoside as only one dominant anthocyanin.     

Anthocyanins of Cephaelis, Cynomorium, Euterpe, Lavatera and Pinanga

The two malonylated pigments, malonylmalvin and malvidin 3-malonylglucoside, were identified in petals of Lavatera maritima, which belongs to the Malvaceae, a family known to synthesise such pigments. Zwitterionic anthocyanins could not be detected in four other newly examined sources and common unacylated pigments were recorded. Thus, the fruits of the palms Euterpe edulis and Pinanga polymorpha have a mixture of cyanidin 3-glucoside and cyanidin 3-rutinoside, while the fruit of Cephaelis subcoriacea is coloured by cyanidin 3-glucoside. The latter pigment was also obtained from the reddish brown inflorescence of the parasitic plant Cynomorium coccineum.     

Cyanidin 3-[6-(p-coumaroyl)-2-(xylosyl)-glucoside]-5-glucoside and other anthocyanins from fruits of Sambucus canadensis.

From the fruits of Sambucus canadensis four anthocyanin glycosides have been isolated by successive application of an ion-exchange resin, droplet-counter chromatography and gel filtration. The structure of the novel, major (69.8%) pigment, cyanidin 3-O-[6-O-(E-p-coumaroyl-2-O-(beta-D-xylopyranosyl)-beta-D- glucopyranoside]-5-O-beta-D-glucopyranoside, was determined by means of chemical degradation, chromatography and spectroscopy, especially homo- and heteronuclear two-dimensional NMR techniques. The other anthocyanins were identified as cyanidin 3-sambubioside-5-glucoside (22.7%), cyanidin 3-sambubioside (2.3%) and cyanidin 3-glucoside (2.1%).     

Acylated anthocyanins and flavonols from purple flowers of Dendrobium cv. ‘Pompadour’

Two rare anthocyanins, cyanidin 3-(6-malonylglucoside)-7,3′-di(6-sinapylglucoside) and the demalonyl derivative, were characterised as the purple floral pigments of Dendrobium cv. ‘Pompadour’. Nine known flavonol glycosides were also identified, including the 3-rutinoside-7-glucosides of kaempferol and quercetin. One new glycoside was detected: the ferulyl ester of quercetin 7-rutinoside-7-glucoside. These flavonoid patterns are typical for plants in the family Orchidaceae.     

Distribution of anthocyanins in aceraceae leaves

The distribution of anthocyanins in spring sprouted and/or autumn coloured leaves of Dipteronia sinensis and Acer (119 taxa) was studied.

Dipteronia contained four cyanidin glycosides: the 3-glucoside, 3-rutinoside, 3-galloylglucoside and 3,5-diglucoside. Acer contained five cyanidin glycosides: 3-glucoside, 3-rutinoside, 3-galloylglucoside, 3-galloylrutinoside and 3,5-diglucoside, two delphinidin glucosides: 3-glucoside and 3-rutinoside and three unidentified anthocyanins. Both Dipteronia and Acer contained the recently reported cyanidin 3-galloylglucoside. The anthocyanin constituents in spring leaves were more complex than those found in autumn coloured leaves: nine in spring and six in autumn. The presence/absence of the major anthocyanins in the spring sprouted leaves of 111 Acer taxa analysed were grouped into 17 distribution patterns. In the autumn the number of anthocyanin distribution patterns was found to be 11. In Acer, cyanidin glycosides were found in 20 sections and delphinidin glycosides in 17 out of the 21 sections analysed. Although the distribution of anthocyanins showed no clear relations among sections, delphinidin glycosides were mainly found in sections Macrantha, Goniocarpa and Saccharina. There were no differences in the pigment constituents in the species native to different countries, such as A. rubrum in North America and A. pycnanthum in Japan, both containing the same pigments: cyanidin 3-glucoside, 3-rutinoside, 3-galloylglucoside, 3-galloylrutinoside and 3,5-diglucoside.