Anthocyanins in the epacridaceae

An examination of 73 species of the family Epacridaceae resulted in the identification of the following anthocyanins: cyanidin 3-galactoside, cyanidin 3-glucoside, cyanidin 3-arabinoside, cyanidin 3-rhamnoside, cyanidin 3-rhamnosylgalactoside, cyanidin 3-rhamnosylglucoside, cyanidin 3-xylosylgalactoside, cyanidin 3-xylosylarabinoside, delphinidin 3-galactoside, delphinidin 3-arabinoside, delphinidin 3-rhamnosylgalactoside, delphinidin 3-rhamnosylglucoside and pelargonidin 3-rhamnosylglucoside. No acylated or 5-substituted anthocyanins were detected in any of the species examined. Evidence of methylated anthocyanidin was found only in one species, Woollsia pungens. The occurrence of cyanidin 3-galactoside and cyanidin 3-arabinoside forms a chemical link between this family and the related Ericaceae.     

Anthocyanins in fruits of Vaccinium Japonicum

Cyanidin-3-arabinoside (54%) and pelargonidin-3-arabinoside (39%) were the main anthocyanins isolated from berries of Vaccinium japonicum. In addition smaller amounts of 3-galactosides of cyanidin (5%) and pelargonidin (2%) were found. The total anthocyanin content in the fruit averaged 113 mg/100 g fresh fruit. This is the first report of pelargonidin derivatives in the genus Vaccinium.     

The occurrence of flavonol arabinosides in the epacridaceae

Foeniculin (quercetin-3-arabinoside) has been detected in 26 species of Epacridaceae. The structural analogues of myricetin and kaempferol have also be     

flavonol glycosides from Callitris Glauca

From the leaves of Callistris glauca myricetin 7-arabinoside, quercitrin, kaempferol 5-rhamnoside, a quercetin arabinoside, quercetin, kaempferol, galangin and shikimic acid were isolated. The natural occurrence of myricetin 7-arabinoside has not previously been reported.     

Synthesis of Flavonoid O-Pentosides by Escherichia coli through Engineering of Nucleotide Sugar Pathways and Glycosyltransferase

Plants produce two flavonoid O-pentoses, flavonoid O-xyloside and flavonoid O-arabinoside. However, analyzing their biological properties is difficult because flavonoids are not naturally produced in sufficient quantities. In this study, Escherichia coli was used to synthesize the plant-specific flavonoid O-pentosides quercetin 3-O-xyloside and quercetin 3-O-arabinoside. Two strategies were used. First, E. coli was engineered to express components of the biosynthetic pathways for UDP-xylose and UDP-arabinose. For UDP-xylose biosynthesis, two genes, UXS (UDP-xylose synthase) from Arabidopsis thaliana and ugd (UDP-glucose dehydrogenase) from E. coli, were overexpressed. In addition, the gene encoding ArnA (UDP-l-Ara4N formyltransferase/UDP-GlcA C-4″-decarboxylase), which competes with UXS for UDP-glucuronic acid, was deleted. For UDP-arabinose biosynthesis, UXE (UDP-xylose epimerase) was overexpressed. Next, we engineered UDP-dependent glycosyltransferases (UGTs) to ensure specificity for UDP-xylose and UDP-arabinose. The E. coli strains thus obtained synthesized approximately 160 mg/liter of quercetin 3-O-xyloside and quercetin 3-O-arabinoside.     

BIOCHEMICAL BASIS OF FLORAL COLOR POLYMORPHISM IN A HETEROCYANIC POPULATION OF TRILLIUM SESSILE (LILIACEAE)

A study of flavonoids occurring within a heterocyanic population of Trillium sessile was made to determine the chemical basis of a common floral color polymorphism in this species. In the study population, three floral color phenotypes (red, pink, yellow) are determined primarily by the presence or absence of anthocyanin compounds in the petal tissue, and secondarily by quantitative differences in the concentration of several flavonol glycosides. Petals of red phenotypes contain both cyanidin 3-arabinoside and 3-diarabinoside, petals of pink phenotypes contain only cyanidin 3-arabinoside, and petals of yellow phenotypes lack cyanidin entirely. Quercetin 3-0-glucoside, quercetin 3-0-arabinoglucoside, quercetin 3–0-arabinogalactoside, and quercetin 3-0-arabinogalactosyl, 7-0-glucoside occur in petals of all three phenotypes but differ in relative amounts. Petals of the red phenotype have mostly 3-0-biosides, but lesser amounts of both quercetin 3-0-glucoside and the 3,7-0-triglycoside. Petals of the pink phenotype contain relatively equal amounts of quercetin mono-, di-, and triglycosides. Petals of the yellow phenotypes contain mostly quercetin 3,7-0-triglycosides, and less mono- and di-glycosides. Small amounts of a quercetin tetraglycoside were detected in petals of both yellow and pink phenotypes, but not in red phenotypes. The enhancement of quercetin polyglycoside biosynthesis in yellow petal phenotypes is attributed to the shunting of dihydroflavonol precursors to synthesis of quercetin compounds when their conversion to anthocyanins is blocked genetically.     

桂火绳中化学成分的研究

从梧桐科火绳属桂火绳中提取分离到22个化合物,经结构鉴定为:羽扇豆醇(1),白桦脂酸(2),齐墩果酸(3),丁香脂素(4),(+)-异落叶松树脂醇(5),东莨菪内酯(6),对羟基肉桂酸(7),二十七碳酸单甘油酯(8),2-十八烯酸单甘油酯(9),sitoindosideⅡ(10),儿茶素(11),表儿茶素(12),表儿茶素3-O-β-D-吡喃木糖甙(13),山奈酚3-O-β-D-吡喃葡萄糖甙(14),5,7,4'-三羟基异黄酮(15),4'-O-methylgallocatechin(16),反式-二氢槲皮素-3-O-α-阿拉伯糖甙(17),顺式-二氢槲皮素-3-O-α-阿拉伯糖甙(18),反式-二氢槲皮素-3-O-β-吡喃葡萄糖甙(19),3,5,7,3',5'-五羟基-4'-甲氧基异黄酮(20),山奈酚-3-O-β-D-吡喃葡萄糖(6→1)-α-L-吡喃鼠李糖甙(21),以及槲皮素3-O-β-D-吡喃葡萄糖(6→1)-β-D-吡喃葡萄糖甙(22),这些化学成分首次从该属植物中分离出来。     

Tissue specific variation of C-glycosylflavone patterns in oat leaves as influenced by the environment

A comparison is made between the flavone patterns accumulating in epidermal tissues and in the mesophyll of oat primary leaves grown in a phytotron and under field conditions. In developing leaves cultivated under standard conditions, varying patterns of two vitexin-derived O-rhamnosides and of one isovitexin O-arabinoside are produced in the basal region as the result of basal meristem activity. These patterns are tissue specific and differ quantitatively in the epidermis and the mesophyll. During the course of subsequent growth and differentiation, this pattern is constant as the compounds are moved upwards due to basipetal leaf growth. In comparison, the flavone patterns generated in the basal section of leaves grown in the field do not vary significantly. There is the additional accumulation of isoorientin O-arabinoside. Again flavone patterns are tissue specific, but in contrast to standard growth they are modified characteristically in those leaf tissues which are already morphologically differentiated. It is possible that the isovitexin moiety of the O-arabinoside is oxidized to the corresponding isoorientin derivative in the mesophyll. Moreover, field-grown leaves show a two-fold increase in flavone content in each leaf epidermis and a six-fold increase in the mesophyll when compared to the corresponding tissues of phytotron-grown leaves.     

Flavonol glycosides of Carya pecan

The flavonol glycosides characterized from the branches of Carya pecan include three new compounds, azaleatin 3-glucoside azaleatin 3-diglycoside and caryatin 3′- (or 4′-) rhamnoglucoside. together with azaleatin 3-rhamnoside. In the leaf tissue, quercetin 3-glucoside, quercetin 3-galactoside, quercetin 3-rhamnoside, quercetin 3-arabinoside and a small amount of kaempferol 3-monomethyl ether were identified.     

Studies on the Chemical Constituents of Rhodiola fastigita S. H. Fu

Rhodiola fastigita is an alpine plant growing at 3300--5400 m above sea level. Seven crystal, compounds were isolated from the rhizome of this plant. They were identified as β- sitosterol, β-sitosterol-3-β-D-galactoside, daucosterol, gallic acid, gallic acid ethyl ester, p-tyrosol and herbacetin-8-arabinoside by IR, MS, H-NMR and chemical method. Daucosterol, β-sitosterol- 3-β-D-galactoside and gallic acid ethyl ester were obtained from the genus Rhodiola L. for the first time.     

Flavonol derivatives of Ichthyothere terminalis

The flavonoids of Ichthyothere terminalis are based upon quercetin, with minor amounts of kaempferol and dihydroquercetin. All glycosides are linked at position-3. Quercetin 3-glucoside, 3-galactoside, and 3-arabinoside comprise the monoglycoside fraction. The diglycoside fraction consists of quercetin 3-rutinoside, 3-rhamnosylgalactoside and 3-digalactoside. The single triglycoside present was shown to be quereetin 3-rhamnosylgalactosylgalactoside. A major constituent of the aglycone fraction was shown to be 3-0-methylquercetin. The flavonoid profile of Ichthyothere terminalis shows marked ditterences from those of the related genera Clibadium and Desmanthodium.     

On the reported molluscicidal activity from Tephrosia vogelii leaves

The rotenoids deguelin and tephrosin were isolated from leaves of Tephrosia vogelii, together with three flavonol glycosides, rutin, isoquercitrin and quercetin 3-O-arabinoside. Although T. vogelii leaves are reportedly toxic to aquatic snails, deguelin and tephrosin were found to have no significant molluscicidal activity.     

The flavonoids of ferns in the isolated genera Loxsoma and Loxsomopsis

Kaempferol and quercetin 3-O-glucosides and 3-O-rhamnoglucosides are common to both Loxsoma cunninghamii and Loxsomopsis costaricensis, but in the former the new flavonoid glycosides, kaempferol and quercetin 3-O-glucoside-7-O-arabinoside have also been identified. The data are consistent with the proposed taxonomic relationship between these geographically isolated genera. Comparative flavonoid chemistry indicates that the Loxsomaceae may be a primitive family, not closely related to the Hymenophyllaceae or the Cyatheaceae.     

Variations in flavonoid patterns within the genus Chondropetalum (restionaceae)

HPLC and chemical analyses of the flavonoids in culms of 11 Chondropetalum species divide the genus into two groups: seven, with glycosides of myricetin larycitin and syringetin; and four, with glycosides of kaempferol, quercetin, gossypetin, gossypetin 7-methyl ether and herbacetin 4′-methyl ether. This chemical dichotomy is correlated with anatomical differences and confirms the view that the genus requires taxonomic revision. HPLC measurements on those species with myricetin derivatives show that taxa with a qualitatively similar pattern of glycosides can be readily separated on quantitative grounds. Syringetin 3-arabinoside and a glycoside of herbacetin 4′-methyl ether are reported for the first time from the genus.     

Flavonol glycosides of Warburgia ugandensis leaves

Four new flavonol gycosides: kaempferide 3-O-beta-xylosyl (1-->2)-beta-glucoside, kaempferol 3-O-alpha-rhamnoside-7,4'-di-O-beta-galactoside, kaempferol 3,7,4'-tri-O-beta-glucoside and quercetin 3-O-[alpha-rhamnosyl (1-->6)] [beta-glucosyl (1-->2)]-beta-glucoside-7-O-alpha-rhamnoside, were characterized from a methanolic leaf extract of Warburgia ugandensis. The known flavonols: kaempferol, kaempferol 3-rhamnoside, kaempferol 3-rutinoside, myricetin, quercetin 3-rhamnoside, kaempferol 3-arabinoside, quercetin 3-glucoside, quercetin, kaempferol 3-rhamnoside-4'-galactoside, myricetin 3-galactoside and kaempferol 3-glucoside were also isolated. Structures were established by spectroscopic and chemical methods and by comparison with authentic samples.     

Flavonoid glycosides from fiveCyathea species

The leaves of 5 fern species of the genusCyathea, i.e.C. fauriei, C. mertensiana, C. leichhardtiana, C. podophylla andC. hancockii, have been chemically analysed. The former 3 species have kaempferol 3-sophoroside (sophoraflavonoloside) and kaempferol 7-rhamnoglucoside as glycosidic components, and the latter 2 species contain kaempferol 3-galactoside (trifolin) and kaempferol 3-rhamnoglucoside (nicotiflorin). In addition, vitexin, orientin, kaempferol 3-glucoside (astragalin), kaempferol 3-rhamnoside (afzelin) and kaempferol 7-arabinoside are detected as common constituents in all the 5 species analysed.     

A new ginsenosidase from Aspergillus strain hydrolyzing 20-O-multi-glycoside of PPD ginsenoside

A ginsenosidase specifically hydrolyzing multi-20-O-glycosides of protopanaxadiol type ginsenosides such as ginsenoside Rb₁, Rb₃, Rb₂ and Rc, named ginsenosidase type II, was isolated and purified from Aspergillus sp.g48p strain. The molecular weight of the enzyme was 60 kDa. Ginsenosidase type II was demonstrated to hydrolyze multi-20-O-glycoside of protopanaxadiol type ginsenoside Rb₁, Rb₃, Rb₂ and Rc; i.e. the ginsenosidase type II hydrolyzes 20-O-β-glucoside of the ginsenoside Rb₁, 20-O-β-xyloside of ginsenoside Rb₃, 20-O-α-arabinoside(p) of ginsenoside Rb₂ and α-arabinoside(f) of ginsenoside Rc to produce mainly ginsenoside Rd, and small amount of Rg₃. However, it did not hydrolyze 3-O-β-glucosides of ginsenoside Rb₁, Rb₃, Rb₂ and Rc which was different with the ginsenosidase type I previously reported, either did not hydrolyze the glycosides of protopanaxatriol type ginsenoside such as ginsenoside Re, Rf and Rg₁, showing significant difference from all previously described glycosidases.     

Flavonoid variations in Avena species

Twenty-five Avena species were investigated for their flavonoids. The flavonoids identified were vitexin, isovitexin, vitexin 2″-rhamnoside, isovitexin 2″-arabinoside, isoswertisin 2″-rhamnoside, tricin 5-glucoside, tricin 7-glucoside and tricin 7-diglucoside. Chemosystematic relationships are discussed.     

外源腐胺促进苹果果皮花青苷积累的效应

为了探讨外源施加腐胺对苹果果皮花青苷合成相关基因的调控效应和果实着色的影响, 摘袋当天对苹果品种红富士(Malus domestica Borkh. ‘Red Fuji’)果实喷施50 mg.L-1腐胺(putrescine, Put), 利用分光光度计和高效液相色谱仪分别对苹果果皮花青苷含量及其组成进行了分析; 利用实时荧光定量PCR法检测了转录调节因子MYB1和5个花青苷合成结构基因的转录水平。结果表明: (1) 外源喷施Put对于苹果果皮中花青苷的积累具有明显的促进效应, 在果实采收时, 处理组果皮中的花青苷含量为对照组的1.9倍; (2) 处理果实的果皮中含有矢车菊素阿拉伯糖苷(cyaniding-3-arabinoside, Cy-3-ara), 而在相同条件下, 对照组中未能检测到Cy-3-ara; (3) Put处理对于转录调节因子MYB1和类黄酮3, 5-糖苷转移酶(UDP-glycose: flavonoid 3-O-glycosyltransferase, UFGT)基因的转录有明显的促进作用, 摘袋后第1天和第3天, Put处理组的MYB1转录水平分别为对照组的1.6和2.0倍, UFGT变化趋势与MYB1类似, 查耳酮异构酶(chalcone isomerase, CHI)、花青素苷元还原酶 (anthocyanidin reductase, ANR)和无色花青素加双氧酶(leucoanthocyanidin dioxygenase, LDOX)等基因的转录水平在Put处理初期也表现为明显上升, 特别是 LDOX基因, 其转录水平在处理后第1天和第3天分别达到对照的10.2和3.8倍。在所研究的基因中, 二氢类黄酮还原酶(dihydroflavonol 4-reductase, DFR)基因是唯一一个经Put处理后其转录水平受到强烈抑制的基因, 且这种抑制作用在摘袋后第3天最为明显, 对照组的DFR转录水平为Put处理组的2.3倍。