Minor betalains in fruits of Hylocereus species

Betacyanins in peel and flesh of fruits of different Hylocereus species were identified by means of GC/MS, electrospray MS/MS, HPLC as well as (1)H and (13)C NMR techniques. As hitherto unknown pigments: betanidin 5-O-(2'-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside, betanidin 5-O-(4'-O-malonyl)-beta-D-glucopyranoside and betanidin 5-O-[(5'-O-E-sinapoyl)-2'-O-beta-D-apiofuranosyl]-beta-D-glucopyranoside were elucidated. The sinapoyl moiety attachment position in the structure of betacyanins was established for the first time. The peel contained a more complex pattern of betacyanins with apiofuranosyl moiety. Other recently identified pigments were also present in the samples and their (1)H or (13)C NMR spectra were recorded. In the case of phyllocactin and its 4'-isomer the migration of the malonyl group was noticed.     

Biosynthesis of malonylated flavonoid glycosides on the basis of malonyltransferase activity in the petals of Clitoria ternatea

The crude malonyltransferase from the petals of Clitoria ternatea was characterized enzymatically to investigate its role on the biosynthetic pathways of anthocyanins and flavonol glycosides. In C. ternatea, a blue flower cultivars (DB) and mauve flower variety (WM) accumulate polyacylated anthocyanins (ternatins) and delphinidin 3-O-(6'-O-malonyl)-beta-glucoside which is one of the precursors of ternatins, respectively. Moreover, WM accumulates minor delphinidin glycosides - 3-O-beta-glucoside, 3-O-(2'-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(2'-O-alpha-rhamnosyl-6'-O-malonyl)-beta-glucoside of delphinidin. These glycosidic patterns for minor anthocyanins in WM are also found among the minor flavonol glycosides in all the varieties including a white flower variety (WW) although the major flavonol glycosides are 3-O-(2'-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(6'-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(2',6'-di-O-alpha-rhamnosyl)-beta-glucoside of kaempferol, quercetin, and myricetin. How do the enzymatic characteristics affect the variety of glycosidic patterns in the flavonoid glycoside biosynthesis among these varieties? While the enzyme from DB highly preferred delphinidin 3-O-beta-glucoside in the presence of malonyl-CoA, it also has a preference for other anthocyanidin 3-O-beta-glucosides. It could use flavonol 3-O-beta-glucosides in much lower specific activities than anthocyanins; however, it could not utilize 3-O-(2'-O-alpha-rhamnosyl)-beta-glucosides of anthocyanins and flavonols, and 3,3'-di- and 3,3',5'-tri-O-beta-glucoside of delphinidin - other possible precursors in ternatins biosynthesis. It highly preferred malonyl-CoA as an acyl donor in the presence of delphinidin 3-O-beta-glucoside. The crude enzymes prepared from WM and WW had the same enzymatic characteristics. These results suggested that 3-O-(2'-O-alpha-rhamnosyl-6'-O-malonyl)-beta-glucosides of flavonoids were synthesized via 3-O-(6'-O-malonyl)-beta-glucosides rather than via 3-O-(2'-O-alpha-rhamnosyl)-beta-glucosides, and that malonylation proceeded prior to glucosylation at the B-ring of delphinidin in the early biosynthetic steps towards ternatins. It seemed that the substrate specificities largely affected the difference in the accumulated amount of malonylated glycosides between anthocyanins and flavonols although they are not simply proportional to the accumulation ratio. This enzyme might join in the production of both malonylanthocyanins and flavonol malonylglycosides as a result of broad substrate specificities towards flavonoid 3-O-beta-glucosides.     

Identification of delphinidin 3-O-(6'-O-malonyl)-beta-glucoside-3'-O-beta-glucoside, a postulated intermediate in the biosynthesis of ternatin C5 in the blue petals of Clitoria ternatea (butterfly pea)

Ternatins are blue anthocyanins found in the petals of Clitoria ternata (butterfly pea). Among them, ternatin C5 (delphinidin 3-O-(6'-O-malonyl)-beta-glucoside-3',5'-di-O-beta-glucoside; 2) has the structure common to all the ternatins, which is characterized by its glucosylation pattern: a 3,3',5'-triglucosylated anthocyanidin. In the course of studying biosynthetic pathways of ternatins, the key enzymatic activities to produce ternatin C5 were discovered in a crude enzyme preparation from the petals of a blue petal line of C. ternatea. When this preparation was tested for activity against several delphinidin glycosides, delphinidin 3-O-(6'-O-malonyl)-beta-glucoside-3'-O-beta-glucoside (6), a postulated intermediate, was found in the reaction mixture, together with three known anthocyanins, which were spectroscopically structurally identified. As a result of structural identification, the following enzymatic activities were identified: UDP-glucose :delphinidin 3-O-(6'-O-malonyl)-beta-glucoside-3'-O-beta-glucoside 5'-O-glucosyltransferase (5'GT), UDP-glucose :delphinidin 3-O-(6'-O-malonyl)-beta-glucoside 3'-O-glucosyltransferase (3'GT), UDP-glucose :delphinidin 3-O-glucosyltransferase, and malonyl-CoA :delphinidin 3-O-beta-glucoside 6'-malonyltransferase. In a mauve petal line, which did not accumulate ternatins but delphinidin 3-O-(6'-O-malonyl)-beta-glucoside in its petal, there were neither 5'GT nor 3'GT activities. Thus, the early biosynthetic pathway of ternatins may be characterized by the stepwise transfer of two glucose residues to 3'- and 5'-position of delphinidin 3-O-(6'-O-malonyl)-beta-glucoside (1; Scheme) from UDP-glucose.     

Triterpenoid saponins and sapogenin lactones from Albizia gummifera

The structures of two new monodesmosidic and bisdesmosidic triterpenoid saponins (1 and 2) and the known compound delta 5-stigmasterol-3-O-beta-D-glucopyranoside (3) as well as two new oleanane type triterpene lactone glycosides 4, 5 and a new sapogenin lactone 6 isolated from the stem bark of Albizia gummifera C.A. Smith (Mimosaceae) have been elucidated as 3-O-?beta-D-glucopyranosyl(1-->2)-[alpha-L-arabinopyranosyl(1-->6) ]-beta-D- glucopyranosyl?-oleanolic acid (1), beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl 3-O-?beta-D-glucopyra-nosyl(1-->2)-[alpha-L-arabinopyrano syl(1-->6)]-beta-D- glucopyranosyl?-oleanolate (2), 3 beta-?O-D-glucopyranosyl-(1-->2)-[O-alpha-L-arabinopyranosyl(1-->6 )] beta-D-glucopyranosyloxy?-machaerinic acid gamma-lactone (4), 3 beta-O-beta-D-glucopyranosiduronic acid (1-->2)-beta-D-glucopyranosyloxy]-machaerinic acid gamma-lactone (5), and A-homo-3a-oxa-5 beta-olean-12-en-3-one-28-oic acid (6), respectively. The complete assignment of the 1H and 13C resonances of 1, 2, 4 and 6 and of the peracetate of 5 were achieved by means of 2D-NMR studies.     

Acylated pelargonidin glycosides in the red-purple flowers of Pharbitis nil.

Four acylated pelargonidin glycosides and pelargonidin 3-sophoroside-5-glucoside were isolated from 23 red-purple cultivars of Pharbitis nil. The acylated anthocyanins were all based on pelargonidin 3-sophoroside-5-glucoside and were identified as the 3-O-[2-O-(beta-D-glucopyranosyl)-6-O-(trans-caffeyl)-beta-D- glucopyranoside]-5-O-(beta-D-glucopyranoside), the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta- D-glucopyranosyl)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta- D-glucopyranosyl)-6-O-(trans-caffeyl)-beta-D-glucopyranoside]-5-O-(beta- D-glucopyranoside); and the 3-O-[2-O-(6-O-(trans-3-O-(beta-D-glucopyranosyl)caffeyl)-beta-D- glucopyranosyl)-6-O-(trans-4-O-(6-O-(trans-3-O-(beta-D- glucopyranosyl)caffeyl)- beta-D-glucopyranosyl)caffeyl)-beta-D-glucopyranoside]-5-O-(beta-D- glucopyranoside). By the analysis of these anthocyanin constituents variously in 23 cultivars, it was found that the red flower colour gradually changed into more bluish colour with increasing numbers of caffeic acid residues in the acylated pelargonidin glycosides. The stabilities of these anthocyanins increased in the order of increasing caffeyl substitution.     

Are the characteristics of betanidin glucosyltransferases from cell-suspension cultures of Dorotheanthus bellidiformis indicative of their phylogenetic relationship with flavonoid glucosyltransferases?

Uridine 5′-diphosphoglucose:betanidin 5-O- and 6-O-glucosyltransferases (5-GT and 6-GT; EC 2.4.1) catalyze the regiospecific formation of betanin (betanidin 5-O-β-glucoside) and gomphrenin I (betanidin 6-O-β-glucoside), respectively. Both enzymes were purified to near homogeneity from cell-suspension cultures of Dorotheanthus bellidiformis, the 5-GT by classical chromatographic techniques and the 6-GT by affinity dye-ligand chromatography using UDP-glucose as eluent. Data obtained with highly purified enzymes indicate that 5-GT and 6-GT catalyze the indiscriminate transfer of glucose from UDP-glucose to hydroxyl groups of betanidin, flavonols, anthocyanidins and flavones, but discriminate between individual hydroxyl groups of the respective acceptor compounds. The 5-GT catalyzes the transfer of glucose to the C-4′ hydroxyl group of quercetin as its best substrate, and the 6-GT to the C-3 hydroxyl group of cyanidin as its best substrate. Both enzymes also catalyze the formation of the respective 7-O-glucosides, but to a minor extent. Although the enzymes were not isolated to homogeneity, chromatographic, electrophoretic and kinetic properties proved that the respective enzyme activities were based on the presence of single enzymes, i.e. 5-GT and 6-GT. The N terminus of the 6-GT revealed high sequence identity to a proposed UDP-glucose:flavonol 3-O-glucosyltransferase (UF3GT) of Manihot esculenta. In addition to the 5-GT and 6-GT, we isolated a UF3GT from D. bellidiformis cell cultures that preferentially accepted myricetin and quercetin, but was inactive with betanidin. The same result was obtained with a UF3GT from Antirrhinum majus and a flavonol 4′-O-glucosyltransferase from Allium cepa. Based on these results, the main question to be addressed reads: Are the characteristics of the 5-GT and 6-GT indicative of their phylogenetic relationship with flavonoid glucosyltransferases? Received: 11 February 1997 / Accepted: 18 April 1997     

Spirostanol saponins of Allium porrum L.

An investigation of the extracts from bulbs of Allium porrum L. has led to the isolation of four spirostanol saponins. Two of them are new compounds and have been identified as: (25R)-5 alpha-spirostan-3 beta, 6 beta-diol 3-O-{O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O- beta -D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside} (3) and (25R)-5 alpha-spirostan-3 beta,6 beta-diol 3-O-{O-beta-D-glucopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->2)-O- [beta-D-xylopyranosyl-(1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D- galactopyranoside} (4). The isolated compounds were evaluated for their antifungal activity.     

Substrate specificity and sequence analysis define a polyphyletic origin of betanidin 5- and 6-<Emphasis Type="Italic">O</Emphasis>-glucosyltransferase from <Emphasis Type="Italic">Dorotheanthus bellidiformis</Emphasis>

Betanidin 6-O-glucosyltransferase (6-GT) is involved in the glycosylation of betacyanins, which replace the chromogenic anthocyanins as flower colorants in the Caryophyllales. The 6-GT cDNA was cloned from a cDNA library of Dorotheanthus bellidiformis (Burm. f.) N.E. Br., and the amino acid and nucleotide sequences were shown to be distinctly different from the corresponding betanidin 5-O-glucosyltransferase (5-GT) from the same plant species. Although both enzymes share very similar substrates, the proteins show only 19% amino acid sequence identity. In contrast, the protein sequence of the 6-GT showed significant identity to GTs from other species and may identify a new cluster of putative anthocyanidin GTs. Therefore, 6-GT and 5-GT apparently have evolved independently from ancestral glucosyltransferases involved in flavonoid biosynthesis.     

Acylated anthocyanins from leaves of Oxalis triangularis

The novel anthocyanins, malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside)-5-O-beta-glucopyranoside (2), malvidin 3-O-(6-O-alpha-rhamnopyranosyl-beta-glucopyranoside)-5-O-(6-O-malonyl-beta-glucopyranoside) (3), malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside)-5-O-(6-O-malonyl-beta-glucopyranoside) (4), malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside) (5) and malvidin 3-O-(6-O-(Z)-p-coumaroyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (6), in addition to the 3-O-(6-O-alpha-rhamnopyranosyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (1) and the 3-O-(6-O-(E)-p-coumaroyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (7) of malvidin have been isolated from purple leaves of Oxalis triangularis A. St.-Hil. In pigments 2, 4 and 5 a malonyl unit is linked to the rhamnose 4-position, which has not been reported previously for any anthocyanin before. The identifications were mainly based on 2D NMR spectroscopy and electrospray MS.     

Light-induced betacyanin and flavonol accumulation in bladder cells of Mesembryanthemum crystallinum

Treatment of the halophyte Mesembryanthemum crystallinum L. (ice plant) (Aizoaceae) with high intensities of white light resulted in a rapid cell-specific accumulation of betacyanins and flavonoids with 6-methoxyisorhamnetin 3-O-?[(2"'-E-feruloyl)-3"'-O-(beta-D- glucopyranosyl)](2"-O-beta-D-xylopyranosyl)]-beta-D-glucopyranoside (mesembryanthin) as the predominant component, within bladder cells of the leaf epidermis. Induced accumulation of these metabolites was first detected 18 h after the initiation of light treatment in bladder cells located at the tip of young leaves followed by the bladder cells located on the epidermis of fully expanded leaves. UV-A light apparently is sufficient to induce accumulation of betacyanins and flavonoids. Application of 2-aminoindan 2-phosphonic acid, a specific inhibitor of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), not only inhibited the accumulation of flavonoids but also reduced betacyanin formation. Based on these observations we suggest these bladder cells as a model system to study regulation of betacyanin and flavonoid biosyntheses.     

梅花‘南京红’花色色素花色苷的分子结构

经特殊颜色反应、纸层析、紫外 -可见光谱、高效液相色谱、气相色谱和核磁共振波谱分析表明 :梅花‘南京红’花色色素的 3种主要花色苷分别是 :花青素 3 氧 (6″ 氧 α 吡喃型鼠李糖基 β 吡喃型葡萄糖 )苷 ,花青素 3 氧 (6″ 氧 没食子酰 β 吡喃型葡萄糖 )苷和花青素 3 氧 (6″ 氧 反式阿魏酰 β 吡喃型葡萄糖 )苷。花青苷在根本上决定着‘南京红’的粉红色花色 ,并可能强化‘南京红’的耐寒能力 ,也奠定了开发和利用该种花色色素的基础。     

New sugars from antigenic lipopolysaccharides of bacteria: identification and synthesis of 3-O-[(R)-1-carboxyethyl]-L-rhamnose, an acidic component of Shigella dysenteriae type 5 lipopolysaccharide.

A new acidic sugar, 3-O-[(R)-1-carboxyethyl]-L-rhamnose (1), has been identified as a constituent of the O-antigenic lipopolysaccharide of Sh. dysenteriae type 5. The structure of 1 has been established by physico-chemical methods and by synthesis. Alkylation of methyl 2,5-di-O-benzyl-alpha-L-rhamnofuranoside (6) with (S)- or (R)-2-chloropropionic acids, followed by removal of the protecting groups, afforded 3-O-[(R)-1-carboxyethyl]-L-rhamnose (9) and 3-O-[(S)-1-carboxyethyl]-L-rhamnose (10), respectively. The properties of 1 coincide with those of 9.     

Synthesis and chemical behaviour of D-glucosyl esters of glutamic acid having the side-chain carboxyl group involved in the glycosidic linkage.

Simultaneous and stepwise deprotection of the fully benzylated D-glucosyl esters of 1-benzyl N-benzyloxycarbonyl- and N-tert-butyloxycarbonyl-L-glutamic acid (1 and 5, respectively) have been examined. Catalytic hydrogenation of 1 led to intramolecular aminolysis to give pyroglutamic acid and D-glucose, but similar treatment in the presence of trifluoroacetic acid afforded both anomers of 1-O-(L-gamma-glutamyl)-D-glucopyranose, which were characterized as trifluoroacetates (2alpha and 2beta) and converted into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(acetyl)-L-glutam-5-oyl]-D-glucopyranose (4) which was also prepared by a definitive method. Hydrogenolysis of 5 gave both anomers of 1-O-[N-(tert-butyloxycarbonyl)-L-gamma-glutamyl]-D-glucopyranose (6), which, upon treatment with trifluoroacetic acid at - 10 degrees, afforded 2alpha and 2beta, respectively. The structure of 6beta was established by its conversion into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-beta-D-glucopyranose (7beta), whereas similar treatment of 6alpha gave a mixture of 1,3,4,6-tetra-O-acetyl-2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (9) and 7alpha. A 1 leads to 2 acyl migration occurred during esterification of the aglycon carboxyl group of 6alpha with diazomethane to give 2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (8).     

Acylated anthocyanins from red radish (Raphanus sativus L.)

Twelve acylated anthocyanins were isolated from the red radish (Raphanus sativus L.) and their structures were determined by spectroscopic analyses. Six of these were identified as pelargonidin 3-O-[6-O-(E)-feruloyl-2-O-beta-D-glucopyranosyl]-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), pelargonidin 3-O-[6-O-(E)-caffeoyl-2-O-(6-(E)-feruloyl-beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), pelargonidin 3-O-[6-O-(E)-p-coumaroyl-2-O-(6-(E)-caffeoyl-beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), pelargonidin 3-O-[6-O-(E)-feruloyl-2-O-(6-(E)-caffeoyl-beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), pelargonidin 3-O-[6-O-(E)-p-coumaroyl-2-O-(6-(E)-feruloyl-beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside), and pelargonidin 3-O-[6-O-(E)-feruloyl-2-O-(2-(E)-feruloyl-beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside]-5-O-(beta-D-glucopyranoside).     

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.     

Ca^2＋-Calmodulin is Involved in Betacyanin Accumulation Induced by Dark in C3 Halophyte Suaeda salsa

The C3 halophyte Suaeda salsa was used to investigate the roles of Ca^2＋, Ca^2＋ channels, and calmodulin （CAM） in betacyanin metabolism. Seeds of S. salsa were cultured in both the dark and light for 3 days. The fresh weight and betacyanin content were much higher in S. salsa seedlings formed in the dark than in seedlings formed in the light. The addition of Ca^2＋ to the half-strength MS nutrient solution promoted betacyanin accumulation in the dark, whereas Ca^2＋ depletion by EGTA suppressed the dark-induced betacyanin accumulation in shoots of S. salsa. The Ca^2＋ channel blocker LaCl3 also inhibited dark-induced betacyanin accumulation. The highest activity of CaM and the maximum betacyanin content decreased by 51% and 45%, respectively, in shoots of S. salsa seedlings treated with the potent CaM antagonist chlorpromazine in the dark. Furthermore, the other CaM antagonist N-（6-aminohexyl）-5-chloro-l-naphthalenesulfonamide （W-7） also inhibited the activity of CaM and dark-dependent betacyanin accumulation, whereas its less active structural analog N-（6-aminohexyl）- 1-naphthalenesulfonamide （W-5） had little effect on the responses to dark of S. salsa seedlings. These results suggest that Ca^2＋, Ca^2＋-regulated ion channels, and CaM play an important role in dark-induced betacyanin accumulation in the shoots of the C3 halophyte S. salsa.     

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.     

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.     

Ca~(2 )-Calmodulin is Involved in Betacyanin Accumulation Induced by Dark in C_3 Halophyte Suaeda salsa

The C_3 halophyte Suaeda salsa was used to investigate the roles of Ca~(2 ),Ca~(2 )channels,and calmodulin(CAM)in betacyaninmetabolism.Seeds of S.salsa were cultured in both the dark and light for 3 days.The fresh weight and betacyanin contentwere much higher in S.salsa seedlings formed in the dark than in seedlings formed in the light.The addition of Ca~(2 )tothe half-strength MS nutrient solution promoted betacyanin accumulation in the dark,whereas Ca~(2 )depletion by EGTAsuppressed the dark-induced betacyanin accumulation in shoots of S.salsa.The Ca~(2 )channel blocker LaCl_3 also inhibiteddark-induced betacyanin accumulation.The highest activity of CaM and the maximum betacyanin content decreased by51% and 45%,respectively,in shoots of S.salsa seedlings treated with the potent CaM antagonist chlorpromazine in thedark.Furthermore,the other CaM antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide(W-7)also inhibited theactivity of CaM and dark-dependent betacyanin accumulation,whereas its less active structural analog N-(6-aminohexyl)-1-naphthalenesulfonamide(W-5)had little effect on the responses to dark of S.salsa seedlings.These results suggest thatCa~(2 ),Ca~(2 )-regulated ion channels,and CaM play an important role in dark-induced betacyanin accumulation in the shootsof the C_3 halophyte S.salsa.