Exudate flavonoid aglycones of Veronica: Ecological and systematic implications

A survey on the distribution of surface flavonoid aglycones in 52 samples of 29 species of Veronica resulted in detection of eight flavone aglycones. Apigenin and luteolin were the most common constituents of the studied exudates, followed by the methylated derivatives apigenin 4′-methyl ether, apigenin 7,4′-dimethyl ether and luteolin 3′-methyl ether. Some intraspecific variations and the main ecological trends of flavonoid aglycone accumulation in Veronica were discussed. The observed exudate profiles appeared to be characteristic for some related groups within the genus, in agreement with the morphological, karyological, molecular and other chemical data.     

Profiling changes in metabolism of isoflavonoids and their conjugates in Lupinus albus treated with biotic elicitor

Liquid chromatography with ultraviolet and mass spectrometric detection was applied to monitor changes in profiles of isoflavonoid glycosides and free isoflavonoid aglycones in Lupinus albus L. Four isoflavonoid aglycones, fourteen isoflavonoid glycosides, four flavonol glycosides and flavone glycoside were identified in lupin tissue after LC/ESI/MS analyses. An elicitor preparation from purified yeast cell wall was used to inject the shoots of 3-week old seedlings or to infiltrate the cut lupin leaves. Qualitative and quantitative changes of isoflavonoids were measured at different time points after elicitation. In elicited lupin seedlings increased amounts of prenylated isoflavone aglycones were identified. The concentrations of glycosidic conjugates of isoflavones present in plant tissue were less affected.     

Iridoids from the flowers of Gardenia jasminoides Ellis and their chemotaxonomic significance

Phytochemical investigation of the flowers of Gardenia jasminoides Ellis (Rubiaceae Gardenia) resulted in the isolation and identification of four iridoid aglycones (1–4) and eleven iridoid glycosides (5–15). This is the first report of the occurrence of these compounds in the genus Gardenia: garjasmine (1), dunnisin (2), α-gardiol (3), β-gardiol (4), diffusoside A (6), diffusoside B (7), genameside C (13), and deacetylasperulosidic acid (14). The chemotaxonomic significance and biosynthetic pathways of these iridoid aglycones (1–4) and iridoid glycosides (5–15) are summarized. Iridoid aglycones and iridoid glycosides are considered as important chemotaxonomic markers in Rubiaceae and this work indicates that the iridoid aglycones (1–4) have a limited distribution in the Rubiaceae.     

Subcellular localization of flavonol aglycone in hepatocytes visualized by confocal laser scanning fluorescence microscope

Flavonoids are widely distributed in the plant kingdom and show various biological activities. The bioavailability of flavonoids in biological samples has conventionally been quantified by high-performance liquid chromatography and mass spectrometry, but with these analytical techniques it is difficult to estimate the subcellular localization of flavonoids in intact cells. In this study, we attempted to examine the localization of flavonoids in cultured cells using a confocal laser scanning fluorescence microscope and mouse hepatoma Hepa-1c1c7 cells. Five flavonol aglycones showed autofluorescence in the cells under the conditions (Ex. 488 nm to Em. 515–535 nm), whereas three flavonol glycosides and eight compounds belonging to other flavonoid subclasses, i.e., flavones, flavanones, and catechins, did not. The autofluorescence of galangin and kaempferol appeared stronger in the nucleus than cytoplasm, suggesting that they are incorporated into the cells and accumulated in the nucleus. The proposed method provided evidence that flavonol aglycones are incorporated into, and accumulated in the nucleus of, hepatocytes.     

Comparative flavonoid glycoside biochemistry as a chemotaxonomic tool in the subdivision of the classical ‘genus’ Lycopodium

A wide variety of novel flavone 5-O-glucosides has been isolated from Lycopodium scariosum. The predominance of tricin derivatives in this species is not in accord with earlier proposed chemotaxonomic definitions of the sub-groups within the classical genus Lycopodium L. cernuum is the first lycopod found to contain flavone C-glycosides and its suggested taxonomic separation from other members of the group is thus substantiated. Flavonoid glycosides appear to offer more definitive chemotaxonomic characters than do the previously used aglycones and modification of the chemical definitions of the sub-groups in these terms is necessary.     

Method of isolating isoflavone aglycones from soya beans

The method of isolating isoflavone aglycones from soya beans has been proposed. The procedure includes the extraction by hot water, glycosides oxidative hydrolysis, aglycones extracting by ethyl acetate and removing the lipophilic substances by means of hexanic extraction. The aglycones outcome is not less than 80%. The preparation obtained contains over 50% of soya bean aglycones.     

A chemotaxonomic study of free flavone aglycones from some Iberian Thymus species

Sixteen free flavone aglycones exuded onto the leaf surfaces have been analysed in twenty-three taxa of genus Thymus growing in the Iberian Peninsula. A chemotaxonomic study of these compounds has been carried out. Correlations with morphological classifications and the usefulness of excreted flavonoids as taxonomic markers are discussed.     

Flavonoid aglycones in the resin of Hazardia squarrosa var. Grindelioides

Thirty three flavonoid aglycones have been identified from the external stem and leaf resin of Hazardia squarrosa var. grindelioides by TLC co-chromatography with authentic samples. The occurrence of compounds with oxygenation at C-6 and C-5′, which are also found in the genus Haplopappus, supports the previously believed close relationship between these two genera.     

Structures of ascaroside aglycones

Free and derivatized aglycones and parent ascarosides of Ascaris lumbricoides and A. columnaris (Nematoda) were isolated by thin-layer and gas chromatography and analyzed by mass spectrometry and polarimetry. Results for monol aglycones confirmed previous chain-length assignments and the location of the l-hydroxyl group at C-2. The major monols of even carbon number possessed a methyl branch on the penultimate carbon (ω ? 1). Diol alycones were entirely unbranched homologues, mainly 31 and 33 carbons long, and had hydroxyl groups on C-2 and C-(ω ? 1). These aglycones were truly symmetrical, for they were optically inactive with the center bearing the glycone in diol ascaroside (C-2), being mostly or entirely the l configuration. Three major features of ascaroside structure—chain length composition of the aglycones, molecular weight of the unusual glycone (a dideoxyhexose), the kind and position of acyl groups—were clearly discernible in the spectra of intact ascarosides.     

Variation in the composition of the heartwood flavonoids of Prunus avium by on-column capillary gas chromatography

A fast and simple extraction procedure, coupled with on-column gas chromatography, has been developed in order to investigate the relative amounts of flavonoids in individual trees within several homogeneous populations of Prunus avium. Eight known flavonoid aglycones were isolated from the heartwood of P. avium and multivariate analysis was employed in order to characterise population groups.     

Analysis of urinary aldosterone metabolites in the guinea-pig

Analysis of urinary metabolites of [1, 2-3H]-aldosterone was performed in the male guinea-pig. Separation of urinary metabolites was carried out by countercurrent distribution followed by DEAE-Sephadex A-25 column chromatography. A major component was obtained which was both hydrolyzable with sulphatase from Helix pomatia and solvolyzable. Paper chromatography of freed steroids revealed the presence of at least two components and the major aglycone cochromatographed with 3 beta, 5 alpha-tetrahydroaldosterone. In order to get more information about the structure of urinary metabolites, a total of 68 mg of aldosterone was injected into three male guinea-pigs and separation of urinary metabolites was performed in a similar manner. A major component obtained showed the color reaction positive for sulphate (modified rhodizonic acid test) and negative for glucosiduronate (naphthoresorcinol test). Gas chromatographic-mass spectrometric analysis of aglycones released from this conjugate revealed the presence of 3 beta, 5 alpha-tetrahydroaldosterone and an another aglycone, tentatively identified as 21-deoxy-tetrahydroaldosterone. Taken together, it was concluded that 3 beta, 5 alpha-tetrahydroaldosterone-monosulphate and 21-deoxy-tetrahydroaldosterone-monosulphate comprised most of urinary conjugated metabolites of aldosterone in the male guinea-pig.     

A novel phenolic acid derivative from buds of Populus lasiocarpa

The lipophilic excretion of winter buds of Populus lasiocarpa in contrast to most other species of the genus does not contain flavonoid aglycones. One of the compounds which are excreted in this plant now could be isolated and identified by chemical methods (hydrolysis, hydrogenation) and spectral analysis (UV, IR, NMR, MS) to be 1,3-p-coumaryl-2-acetyl-glycerol.     

Flavonoid patterns in the farina of goldenback and silverback ferns

Most species of the fern genus Pityrogramma show a farinose indument caused by a deposit of exuded flavonoid aglycones. Some 220 samples, comprising 14 species, have been studied for the chemical composition of their farinas. Flavones, flavonols and C-methylated flavonoid are rarely found. The presence of certain chalcones and dihydrochalcones, however, appears to be to some extent characteristic for the genus. In some cases the farina flavonoid pattern is species-specific; in one species also variety-specific patterns and even chemotypes are observed. In general, the flavonoid chemistry in Pityrogramma parallels frond morphology to a great extent. This supports the concept that around a core of generalized species a few variant species exist which are best treated as belonging to Pityrogramma.     

Flavonoid distribution in Arnica subgenus chamissonis

Twenty-eight flavonoid aglycones have been identified from Arnica chamissonis, A. longifolia, A. amplexicaulis, A. mollis, and A. parryi of the subgenus Chamissonis of the genus Arnica. The flavonoid pattern was largely homogeneous. Only A. mollis is an exception by the occurrence of 7-methylation.     

Purification and identification of dTDP-oleandrose, the precursor of the oleandrose units of the avermectins

The nucleotide sugar precursor of the oleandrose units of the avermectins has been purified from a mutant of Streptomyces avermitilis, which does not synthesize any avermectins but which converts avermectin aglycones to their respective disaccharides. This precursor has been identified as dTDP-oleandrose. The purification was achieved by anion exchange and reverse phase high performance liquid chromatography. The purified nucleotide sugar had an absorption spectra characteristic of thymidine, released dTMP when treated with phosphodiesterase, and possessed an NMR spectrum in which three resonances characteristic of oleandrose were seen in addition to the thymidine signals. The enzyme, avermectin aglycone dTDP-oleandrose glycosyltransferase, which catalyzes the stepwise addition of oleandrose to the avermectin aglycones, has been demonstrated in cell-free extracts and (NH4)2SO4 fractions of cell-free extracts of S. avermitilis. The enzyme is specific for dTDP-oleandrose as the glycosyl donor but utilizes all avermectin aglycones as glycosyl acceptors. The stoichiometry between dTDP-oleandrose consumed in the reaction and oleandrose units transferred to the avermectin mono- and disaccharide was found to be 1:1.     

云南野生翠雀属花卉资源

本文报道云南省野生翠雀属花卉资源的特点、分布、观赏性状及园林用途,并提出开发利用建议.     

Partial purification and properties of glucosyltransferase fromStreptomyces aureofaciens

Differential centrifugation, precipitation with ammonium sulphate and chromatography on DEAE-cellulose led to a twenty-fold purification of glucosyltransferase from Streptomyces aureofaciens B 96. The Michaelis constants for glucosyluridyl diphosphate (UDP-glucose) was 10.8 microM for 1,2-dihydroxy-9,10-anthraquinone (alizarin) 110 microM; the maximum rate of glucosylation reaction was 5.32 mumol per s per mg protein. The pH optimum was at 7.1; the flat temperature optimum was at 30 degrees C. Using some hydroxy derivatives of 9,10-anthraquinone it was found that the production of glucosides from aglycones with alpha-hydroxyl groups was about 1/8 of the values obtained with beta-hydroxyl substrates. In both types of aglycones the presence of another hydroxyl group led to a higher glucoside production.     

鹅绒藤属及其近缘属的化学分类——兼论Vincetoxicum的恢复问题

本文讨论了鹅绒藤属及其近缘属的分类问题。根据这类植物所含的C_(21)甾体甙元结构类型的分类,生源合成途径假说,以及C_(21)甾休甙元的分布,结合形态学的比较分析和其它证据,认为Vincetoxicum是一个脱胎于Cynanchum,但又较之进化的自然类群,应恢复其属级地位。列举了国产白前属全部分类群的正确学名,其中包括15个新组合,1个改级新组合和1个新改级。     

Distribution of imino acids in Ptelea and their probable ecological significance

Seed and leaf extracts of 124 populations of all three species of Ptelea were analysed by paper chromatography and high voltage electrophoresis for their imino acids. Proline and pipecolic acid were found to have a wide distribution in the genus with high concentrations of both imino acids restricted to the xeric forms. The ecological significance is discussed.     

Flavonoids and the taxonomy of Camarea (Malpighiaceae)

Camarea is a South-American endemic genus comprising eight species. In the present work leaf flavonoids of seven species of Camarea were identified, aiming to evaluate the usefulness of their distribution as a taxonomic aid. A total of 12 flavonoids were isolated and identified. Free aglycones, such as apigenin, chrysoeriol, kaempferol and quercetin, as well as 7-O-glycosides of apigenin and luteolin, 3-O-glycosides of kaempferol and quercetin were identified. Flavonoid distribution in Camarea species, taking into account aglycones and aglycone moieties of glycosides, was used to obtain a phenogram of chemical affinities. Apigenin, chrysoeriol and kaempferol were the main discriminating characters for links establishment. The resultant tree suggests the links: 1) Camarea hirsuta, Camarea affinis and C. affinis × C. hirsuta; 2) Camarea elongata and Camarea axillaris; 3) Camarea sericea and Camarea humifusa. The results are in agreement with morphological similarities and disagree with several points of n-alkane evidence. The results support the recognition of Camarea triphylla as synonymy of C. axillaris.