Delphinidin accumulation is associated with abnormal flower development in petunias

The relative floral anthocyanidin contents of 195 commercial petunias with floral colours other than white and yellow were determined using HPLC, and the presence of five anthocyanidins (cyanidin, peonidin, delphinidin, petunidin, and malvidin) was confirmed. Pelargonidin was not detected, and delphinidin was not a major component. Using a principal component analysis of the relative anthocyanidin contents, the petunias were classified into three phenotype-groups accumulating cyanidin, peonidin, or malvidin, (plus petunidin) as the major anthocyanidin. A fourth phenotype was segregated in the progeny obtained by self-pollinating an F1 hybrid of the malvidin group; this accumulated delphinidin 3-glucoside in a markedly crumpled corolla-limb (delphinidin group). Such inferior floral traits, associated with the accumulation of delphinidin 3-glucoside, are thought to be the driving force that removed the delphinidin group from commercial petunias. A comparison of flowers of the delphinidin group and those of the other groups may provide a useful tool towards a deeper understanding of how anthocyanin biosynthesis relates to normal development of the corolla.     

Methylation of anthocyanins by cell-free extracts of flower buds of Petunia hybrida

An O-methyltransferase activity which catalyses the methylation of anthocyanins was extracted from flowerbuds of Petunia hybrida. The methyltransferase uses S-adenosyl-l-methionine as methyl donor. Only anthocyanidin 3(p-coumaroyl)rutinosido-5-glucoside was methylated. No methylating activity towards anthocyanidins, anthocyanidin 3-glucosides, anthocyanidin 3-rutinosides, caffeic acid or p-coumaric acid could be detected.     

紫背天葵叶片中花青素种类及合成调控基因转录组分析

为获取紫背天葵(Cynura bicolor DC.)叶片中花青素种类及其合成调控基因等信息,该试验以紫背天葵叶背面紫色以及经处理叶背面几乎全绿(对照)的叶片为材料,进行转录组测序分析,同时进行6个相关差异表达基因的qRT-PCR分析和6种花青素苷元的HPLC检测,以揭示紫背天葵特有的花青素苷元及其合成调控关键基因信息。结果表明:(1)在紫背天葵中共获得14个花青素苷元及32个花青素合成调控基因信息,其中表达量差异显著下调的4个基因为Pg(c11692)、Cy(c42112)、ANS(c38551)和3GT(c9064),表达量差异显著上调的2个基因是D FR(c35961)和3GT(c20283)。(2)qRT-PCR检测结果显示,上述6个基因在2种紫背天葵叶中的表达趋势(上调或下调)与转录组测序结果完全一致,但转录组测序检测到的表达趋势差异倍数比qRT-PCR检测结果更加明显。(3)HPLC分析显示,紫背天葵叶中均未检测到Dp、Pt、Pn及Mv等4类花青素苷元,但紫背天葵叶中富含Cy花青素苷元,且背面紫色的叶中Cy类花青素苷元含量(62.21 mg/kg)显著高于绿色叶对照(6.86 mg/kg);背面紫色和全绿叶中的Pg花青素苷元含量均低于0.43 mg/kg。研究推测,Cy和Pg花青素苷元在绿叶紫背天葵(对照)中含量显著降低可能是因为存在1个ANS和1个3GT正调控以及1个DFR和1个3GT负调控所致。     

The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin

The hydrolysis of proanthocyanidins to anthocyanidins in n-BuOH-HCl (95:5) has been shown to be an autoxidation, the yield of anthocyanidin being critically dependent on trace metal-ion impurities. Reproducible yields of anthocyanidin may be achieved if iron (III) salts are added to the reaction medium, and a standard method of analysis of proanthocyanidins based on use of an n-BuOH-HCl-Fe^III mixture is given. The ratio of absorbance maxima of the cyanidin (550 nm) produced to that near 280 nm for the original procyanidin polymer solution was ～ 3.5.     

Anthocyanins and anthocyanidins in the flowers of Aconitum (Ranunculaceae)

The presence of anthocyanidins and anthocyanins were analyzed in flowers of 30 taxa of Aconitum. Delphinidin was detected as a major anthocyanidin from the hydrolysate of 29 taxa with violet and violet-blue flowers. Pelargonidin was identified as a major anthocyanidin in one taxon with white flowers (partially pale reddish purple; White group N155C by R.H.S. Colour Chart). This is the first reported detection of pelargonidin as a major anthocyanidin from Aconitum flowers. Pelargonidin was also found in ten taxa as a minor anthocyanidin, whereas cyanidin was detected from the flowers of all 30 taxa as a minor anthocyanidin.Two anthocyanins polyacylated by p-hydroxybenzoic acids, violdelphin and monodeacylcampanin were identified from 29 taxa with violet and violet-blue flowers as major anthocyanins. This is the first reported isolation of monodeacylcampanin from Aconitum flowers. The structures of these two anthocyanins were elucidated on the basis of Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS).     

ANTHOCYANIN SYNTHESIS IN SALPIGLOSSIS SINUATA

Measurements were made of the growth and pigment content of developing flower buds of Salpiglossis sinuata. From the time the buds were approximately 10 mm long they grew in length exponentially until they reached their final length. The logarithm of bud length increased linearly with time and served as a convenient morphological index on which to relate the progress of anthocyanin synthesis. Buds shorter than about 42 mm had no anthocyanin, but when buds reached this length, anthocyanin production was initiated and proceeded rapidly. The maximum relative pigment concentration (pigment/mg fresh weight) was attained by the buds about 17 hr after the initiation of pigment synthesis. In the mahogany-colored variety used in these studies, two anthocyanidins were found and identified as cyanidin and delphinidin. Buds excised from the plants could be cultured in vitro. Buds started in culture at a length of 30–35 mm when they contained no anthocyanins developed pigment during their growth. The amount of pigment formed increased with increasing light intensity, while only small amounts of pigment could be formed in buds cultured in darkness. The anthocyanidins of these cultured buds were the same as those of the intact flowers, but the ratio of delphinidin to cyanidin decreased with decreasing light intensity. Brief daily irradiation of dark-grown buds with red, far-red or blue light did not increase pigment synthesis nor change the anthocyanidin ratio. If buds were placed in culture at 20–25 mm and grown in darkness, they developed a third anthocyanidin, identified as malvidin, which was not present in intact flowers, light-grown buds or 30–35-mm buds cultured in darkness.     

Studio sulla colorazione da antocianidine in alcune specie della flora italiana

Abstract

Flower colour and anthocyanidin pigments in some species of the Italian flora.—The anthocyanidin pigments, cyanidin and peonidin, of Corydalis cava and C. solida have been identified. The chromatic variation of C. cava is due to quantitative variation of the pigments. Only quantitative differences exist between the two species C. cava and C. solida. The pigments are absent in the white flowers.

The pigments of Pulmonaria visianii in all flower ages are delphinidin, petunidin and malvidin. The blueing of flowers with ageing depends on pH; being 5.6 for red, 6.0 for purple and 6.7 for blue flowers.     

Sodium borohydride reduction of anthocyanidins

The reduction of anthocyanidins with NaBH₄ in EtOH or MeOH produces inter alia racemates of epicatechins. Thus, the (±) racemates of 3′,5′-di-O-methylepigallocatechin, 3′-O-methylepigallocatechin, and 3′-O-methylepicatechin have been identified as the reduction products of malvidin, petunidin, and peonidin, respectively, by their UV, MS and NMR spectra.     

Three acylated anthocyanins and a flavone glycoside in violet-blue flowers of Saintpaulia ‘Thamires’

Three new acylated anthocyanidin 3-rutinoside-5-glucosides were isolated from the violet-blue flowers of Saintpaulia ‘Thamires’ (Saintpaulia sp.) along with a known flavone glycoside. Three new acetylated anthocyanins were determined to be 3-O-[6-O-(4-O-(acetyl)-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-(β-glucopyranoside)s of malvidin (pigment 1), peonidin (pigment 2), and pelargonidin (pigment 3) by chemical and spectroscopic methods. HPLC analysis revealed that malvidin 3-O-acetylrutinoside-5-O-glucoside existed as a dominant pigment in the violet-blue flowers. Moreover, the isolated flavone was identified to be apigenin 4′-O-β-glucuronopyranoside (pigment 4).On the visible absorption spectral curves of fresh violet-blue petals and in their crude extracts in pH 5.0 buffer solution, two characteristic absorption maxima at 547 and 577 nm, with a shoulder near 620 nm, were observed. In contrast, the absorption curves of malvidin 3-O-acetylrutinoside-5-O-glucoside and its deacyl anthocyanin exhibited only one maximum at 535 nm in pH 5.0 buffer solution, and its color was violet and soon fell into decay.However, by addition of apigenin 4′-O-glucuronide, the color of malvidin 3-O-acetylrutinoside-5-O-glucoside changed from violet to violet-blue, similar to that of the fresh flower in pH 5.0 buffer solution. The absorption curve of its violet-blue solution exhibited two similar absorption maxima at 547 and 577 nm, with a shoulder near 620 nm. These results suggest that intermolecular copigmentation between malvidin 3-O-acetylrutinoside-5-O-glucoside and apigenin 4′-O-glucuronide may be responsible for the violet-blue flower color of S. ‘Thamires’.     

Genetic control of biosynthesis of anthocyans in sweet pea (<Emphasis Type="Italic">Lathyrus odoratus</Emphasis> L.) flowers

Inheritance of anthocyanidins in sweet pea flowers was studied. A relationship was revealed between the colour of flowers in plants of mutant lines and the presence of different types of anthocyanidins in petal cells. Forms synthesizing anthocyanidins with a large number of OH groups in the B ring of their structure were found to be dominant with respect to less hydroxylated pigments. The functions of three earlier undescribed nonallelic genes of sweet pea have been identified for the first time. Gene R determines the synthesis of pelargonidin that has one OH group in the B ring. The formation of dihydroxylated cyanidin is controlled by the Sm1 gene. Gene E1 is involved in the biosynthesis of trihydroxylated delphinidin. A scheme of genetic control of anthocyanidin biosynthesis in sweet pea flowers is proposed on the basis of the data obtained. Possible mechanisms of the action of the identified genes are discussed     

Distribution pattern of anthocyanidins and anthocyanins in polygonaceous plants

Forty-six polygonaceous plants were examined regarding the nature and amount of anthocyanidins which were obtained as the HCl-hydrolyzate of leaf proanthocyanidins. All of the plants examined contained cyanidin in common in their hydrolyzed leafextracts. From this survey, at least three groups of plants may be distinguished; the first containing only cyanidin, the second delphinidin in addition to cyanidin and the third an unknown anthocyanidin (called PA-X) and cyanidin. Of the plants examined,Polygonum cuspidatum leaves yielded cyanidin in the largest amounf. There were no geographical and seasondl variations of the distribution pattern of pigments in the plants, and also no variation of anthocyanidin-types was observed in young and mature leaves. A further survey of anthocyanins in the plants revealed that delphinidin glycosides are present in the sepals ofPolygonum nepalense andP. thunbergii.     

Structural basis for acceptor‐substrate recognition of UDP‐glucose: anthocyanidin 3‐O‐glucosyltransferase from Clitoria ternatea

UDP‐glucose: anthocyanidin 3‐O‐glucosyltransferase (UGT78K6) from Clitoria ternatea catalyzes the transfer of glucose from UDP‐glucose to anthocyanidins such as delphinidin. After the acylation of the 3‐O‐glucosyl residue, the 3′‐ and 5′‐hydroxyl groups of the product are further glucosylated by a glucosyltransferase in the biosynthesis of ternatins, which are anthocyanin pigments. To understand the acceptor‐recognition scheme of UGT78K6, the crystal structure of UGT78K6 and its complex forms with anthocyanidin delphinidin and petunidin, and flavonol kaempferol were determined to resolutions of 1.85 Å, 2.55 Å, 2.70 Å, and 1.75 Å, respectively. The enzyme recognition of unstable anthocyanidin aglycones was initially observed in this structural determination. The anthocyanidin‐ and flavonol‐acceptor binding details are almost identical in each complex structure, although the glucosylation activities against each acceptor were significantly different. The 3‐hydroxyl groups of the acceptor substrates were located at hydrogen‐bonding distances to the Nε2 atom of the His17 catalytic residue, supporting a role for glucosyl transfer to the 3‐hydroxyl groups of anthocyanidins and flavonols. However, the molecular orientations of these three acceptors are different from those of the known flavonoid glycosyltransferases, VvGT1 and UGT78G1. The acceptor substrates in UGT78K6 are reversely bound to its binding site by a 180° rotation about the O1–O3 axis of the flavonoid backbones observed in VvGT1 and UGT78G1; consequently, the 5‐ and 7‐hydroxyl groups are protected from glucosylation. These substrate recognition schemes are useful to understand the unique reaction mechanism of UGT78K6 for the ternatin biosynthesis, and suggest the potential for controlled synthesis of natural pigments.     

Human tumor cell growth inhibition by nontoxic anthocyanidins, the pigments in fruits and vegetables

Anthocyanidins, the aglycones of anthocyanins, impart brilliant colors in many fruits and vegetables. The widespread consumption of diets rich in anthocyanin and anthocyanidins prompted us to determine their inhibitory effects on human cancer cell proliferation. Five anthocyanidins, cyanidin (1), delphinidin (2), pelargonidin (3), petunidin (4) and malvidin (5), and four anthocyanins, cyanidin-3-glucoside, cyanidin-3-galactoside, delphinidin-3-galactoside and pelargonidin-3-galactoside were tested for cell proliferation inhibitory activity against human cancer cell lines, AGS (stomach), HCT-116 (colon), MCF-7 (breast), NCI H460 (lung), and SF-268 (Central Nervous System, CNS) at 12.5-200 microg/mL concentrations. The viability of cells after exposure to anthocyanins and anthocyanidins was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) colorimetric methods. The anthocyanins assayed did not inhibit cell proliferation of cell lines tested at 200 microg/mL. However, anthocyanidins showed cell proliferation inhibitory activity. Malvidin inhibited AGS, HCT-116, NCI-H460, MCF-7 and SF-268 cell growth by 69, 75.7, 67.7, 74.7 and 40.5%, respectively, at 200 microg/mL. Similarly, pelargonidin inhibited AGS, HCT-116, NCI H460, MCF-7 and SF-268 cell growth by 64, 63, 62, 63 and 34%, respectively, at 200 microg/mL. At 200 microg/mL, cyanidin, delphinidin and petunidin inhibited the breast cancer cell growth by 47, 66 and 53%, respectively. This is the first report of tumor cell proliferation inhibitory activity by anthocyanidins.     

Synthesis of malvidin and petunidin in pigmented tissue cultures ofPetunia hybrida

Summary In petunia cells culturedin vitro anthocyanin synthesis is usually repressed resulting in white/ yellow cells. However, we observed that in petunia strain AK-5000 purple cells appeared at a frequency of about 5 × 10^–5. Analysis of the pigments showed that these cells contained the same anthocyanidins (petunidin and malvidin) as found in corollas of the parental plants. This suggests an induction of anthocyanin synthesis in these cells. In white/yellow cells, from which these pigmented cells originated, we could not observe any of the known precursors of these pigments.     

ABCC1, an ATP Binding Cassette Protein from Grape Berry,Transports Anthocyanidin 3-O-Glucosides

Accumulation of anthocyanins in the exocarp of red grapevine (Vitis vinifera) cultivars is one of several events that characterize the onset of grape berry ripening (véraison). Despite our thorough understanding of anthocyanin biosynthesis and regulation, little is known about the molecular aspects of their transport. The participation of ATP binding cassette (ABC) proteins in vacuolar anthocyanin transport has long been a matter of debate. Here, we present biochemical evidence that an ABC protein, ABCC1, localizes to the tonoplast and is involved in the transport of glucosylated anthocyanidins. ABCC1 is expressed in the exocarp throughout berry development and ripening, with a significant increase at véraison (i.e., the onset of ripening). Transport experiments using microsomes isolated from ABCC1-expressing yeast cells showed that ABCC1 transports malvidin 3-O-glucoside. The transport strictly depends on the presence of GSH, which is cotransported with the anthocyanins and is sensitive to inhibitors of ABC proteins. By exposing anthocyanin-producing grapevine root cultures to buthionine sulphoximine, which reduced GSH levels, a decrease in anthocyanin concentration is observed. In conclusion, we provide evidence that ABCC1 acts as an anthocyanin transporter that depends on GSH without the formation of an anthocyanin-GSH conjugate.     

An unusual acylated malvidin 3-glucoside from flowers of Impatiens textori Miq. (Balsaminaceae)

Acylated malvidin 3-glucoside was isolated from the purple flowers of Impatiens textori Miq. as a major anthocyanin component along with malvidin 3-(6″-malonyl-glucoside). Its structure was elucidated to be malvidin 3-O-[6-O-(3-hydroxy-3-methylglutaryl)-β-glucopyranoside] by chemical and spectroscopic methods.     

蕨类植物花青素和原花青素成分及含量分析

以7目14科共44种蕨类植物为材料,对它们的花青素、原花青素和总黄酮含量进行检测。结果显示,44种蕨类植物均含有花青素,较为进化的水龙骨目植物的总花青素平均含量明显高于其它蕨类植物。矢车菊素、飞燕草素和天竺葵素是蕨类植物主要的花青素类型,其中乌毛蕨科植物富含矢车菊素,鳞毛蕨科植物富含飞燕草素。本研究中大部分蕨类含有原花青素,水龙骨目植物的原花青素平均含量高于其它蕨类。研究结果表明,蕨类植物中花青素和原花青素等黄酮类化合物的分布与植物科属相关,推测花青素与蕨类植物的生长发育和抗逆过程相关。