Passibiflorin,epipassibiflorin and passitrifasciatin: cyclopentenoid cyanogenic glycosides from Passiflora

An epimeric mixture of two novel cyclopentenoid cyanogenic glycosides, passibiflorin [1-(6-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-4-hydroxycyclopent-2-en-1-nitrile] and its C-1 epimer, epipassibiflorin, has been isolated from Passiflora biflora and P. talamancensis. The structures were determined by means of ¹H NMR and ¹³C NMR. Another novel cyclopentenoid cyanogenic glycoside, passitrifasciatin [1-(4-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-4-hydroxycyclopent-2-en-1-nitrile] is described from Passiflora trifasciata. The structure was determined by means of ¹H NMR. The identification of the sugar moieties was made by HPLC and TLC. The isolation of a β-1 → 4 and a β-1 → 6-rhamnoglucoside of cyclopentenoid cyanogens from three species of subgenus Plectostemma of Passiflora suggests that diglycosides of this type are taxonomically diagnostic for the section.     

Chemical constituents from the root of Damnacanthus officinarum Huang

The present phytochemical investigation on Damnacanthus officinarum Huang led to the isolation of a new anthraquinone glycoside named digiferruginol-11-O-β-gentiobioside, along with six known compounds, including anthraquinone glycosides, iridoid glycoside and etc. In the study, compounds (2–7) were isolated for the first time from D. officinarum Huang and Damnacanthus genus. The found of compounds (1–4, 6 and 7) indicate a close relationship between D. officinarum Huang and Morinda officinalis, which may be as chemotaxonomic markers for the tribe Morindeae     

Synthesis of 5-thio-D-galactose

A synthesis of 5-thio-D-galactose, in the form of its crystalline, anomeric methyl glycopyranosides, is described. Compounds prepared as intermediates included ethyl 2,3-di-O-(tert-butyldimethylsilyl)-5,6-O-carbonyl-β-D-galactofuranoside, the corresponding 5,6-dideoxy-5,6-epithio derivative, and ethyl 2,3,6-tri-O-acetyl-5-S-acetyl-5-thio-β-D-galactofuranoside. On methanolysis, the latter afforded methyl 5-thio-α-D-galactopyranoside which, in turn, was transformed into methyl 5-thio-β-D-galactopyranoside. Acetolysis proved to be less satisfactory for incorporation of the sulfur atom into a pyranose ring-form. Characteristics of the ¹³C-n.m.r. spectra of derivatives of 5-thio-D-galactose are described, including the fact that ¹J_C,H values for the anomeric pyranosides differ by only 1–3 Hz, as compared with ≈ 10 Hz for their oxygen analogs.     

Isolation and Partial Characterization of Four Host-specific Toxins of Helminthosporium maydis (Race T)

Helminthosporium maydis, race T, produces four host-specific toxins in culture. These have been designated toxins I, II, III, and IV. A method for isolation and purification of the four toxins is presented, and the criteria of purity of preparations of toxins I, II, and III are given. Toxins I and II are chemically similar and yield the same molecular ion when subjected to mass spectrometry, while toxin III appears to be a glycoside of a compound related to toxins I and II. Toxins I, II, and III can be biologically derived from ¹⁴C-mevalonic acid or ¹⁴C-acetate, permitting preparation of ¹⁴C-labeled toxins. Some chemical, spectral, and chromatographic properties of toxins I, II, and III are presented, and these data are discussed relative to the possible structure of the three compounds. In addition, four host-specific toxins have been isolated from corn infected with H. maydis (race T). These toxins are recovered in the same fractions as toxins I, II, III, and IV using the isolation procedure described here. Three of the toxins isolated from infected corn cannot be distinguished from toxins I, II, and III on the basis of infrared spectra or chromatographic mobility.     

A leptosidin glycoside from leaves of Cyperus scariosus

Phytochemical examination of the leaves of Cyperus scariosus resulted in the isolation and identification of a new glycoside, leptosidin 6-O-β-d-glucopyranosyl-O-α-l- rhamnopyranoside.     

Saccharopine and 2-aminoadipic acid in Reseda odorata

2(S),2′(S)-N⁶-(2′-Glutaryl)lysine (l-saccharopine) and 2(S)-2-aminoadipic acid have been isolated from Reseda odorata. When traditional isolation procedures are used l-pyrosaccharopine (5(S),5′(S)-N-(5′-amino-5′-carboxy-pentyl)-2-pyrrolidone-5-carboxylic acid) is formed from l-saccharopine by lactamisation. The degree of lactamisation during various isolation steps has been studied, The amino acids were identified by IR and PMR spectroscopy and the configurations established by enzymic and polarimetric analyses. The contents of saccharopine and 2-amino-adipic acid have been determined relative to the total nitrogen content at various stages in the growth cycle of R. odorata.     

An acylated allose-containing 8-hydroxyflavone glycoside from Veronica filiformis

A novel flavone glycoside has been obtained from the whole plant of Veronica filiformis and identified by means of ¹³C NMR spectroscopy as isoscutellarein 4′-methyl ether 7-O-β-(6?-O-acetyl-2″-O-allosylglucoside). The related isoscutellarein glycoside is also present. This is the first report of 2-allosylglucose as a disaccharide unit of flavonoids. ¹³`C NMR data on some A-ring trioxygenated flavonoids are also presented.     

Arylbenzofurans from Dalbergia parviflora

The isolation of two polysubstituted arylbenzofurans from the heartwood of Dalbergia parviflora is described. Their structures were elucidated mainly by spectroscopic techniques (UV, IR, ¹H and ¹³C NMR). They were named parvifuran (5-hydroxy-6-methoxy-3-methyl-2-phenylbenzofuran) and isoparvifuran (5-hydroxy-6-methoxy-2-methyl-3-phenylbenzofuran) and are the first compounds of this class isolated from a Dalbergia species.     

Passicoccin: a sulphated cyanogenic glycoside from Passiflora coccinea

A novel cyclopentenoid cyanogenic glycoside (1-(6-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-cyclopent-2-en-1-nitrile-4-sulphate) has been isolated from Passiflora coccinea. The structure was determined by means of the ¹H and ¹³C NMR spectrum of the sulphate and its corresponding acetate derivative. Identification of the sugar constituents was made by HPLC and TLC. Passicoccin is so far unique to subgenus Distephana and its presence here is evidence for a phylogenetic relationship between Distephana and subgenera Granadilla and Tacsonia.     

Disaccharide 1-phosphate polymers of some representatives of the Bacillus subtilis group

Disaccharide 1-phosphate polymers as well as teichoic acids of various structures have been found in the cell walls of the representatives of the Bacillus subtilis group, namely Bacillus subtilis subsp. spizizenii VKM B-720 and VKM B-916, B. subtilis VKM B-517, and Bacillus vallismortis VKM B-2653^T. Disaccharide 1-phosphate polymers are composed of repeating units of the following structure: -P-4)-β-D-GlcpNAc-(1→6)-α-D-Galp-(1-, the N-acetylglucosamine residues are partially acetylated at positions O3 and O6 (VKM B-720 and VKM B-916); -P-4)-β-D-Glcp-(1→6)-α-D-GlcpNAc-(1-, the glucopyranose residues are partially acetylated at positions O2 or O3 (VKM B-517); -P-6)-α-D-GlcpNH ₃ ⁺ /α-D-GlcpNAc-(1→2)-α-D-Glcp-(1-, the N-acetylglucosamine residues are partially deacetylated (VKM B-2653^T). The structures of the two last disaccharide 1-phosphate polymers have not been reported so far for Gram-positive bacteria. The teichoic acids in the studied strains are O-D-alanyl-1,5-poly(ribitol phosphates) substituted with β-D-glucopyranose (VKM B-517, VKM B-720, VKM B-916) or 2-acetamido-2-deoxy-β-D-glucopyranose (VKM B-2653^T). The structures of the phosphate-containing polymers have been studied by chemical methods and by NMR spectroscopy.     

Purification of pigeon liver malic enzyme by affinity chromatography

A simple and rapid method for the purification of malic enzyme (EC 1.1.1.40) from pigeon liver is described. Malic enzyme in the crude tissue extract was partially purified by heat treatment, ammonium sulfate fractionation, and DEAE-cellulose chromatography. Final purification was achieved by affinity chromatography on immobilized N⁶-(6-aminohexyl)-adenosine 2′,5′-bisphosphate. Apparently homogeneous enzyme was obtained in 2 days with 54% yield.     

Über die orthoesterbildung als konkurrenzreaktion zur glykosylierung

1,2-(Alkyl orthoacetates) (orthoesters) were obtained in good yields from acetylated cis-glycosyl halides and alcohols in tetrahydrofuran in the presence of silver salicylate. The scope and the possible mechanism of the reaction were investigated. The presence of an intermediate oxonium ion (13) derived from the sugar derivative and tetrahydrofuran was deduced, from the occurrence of 4-bromobutyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside as a by-product of the reaction, and from semi-quantitative kinetic investigations. After an intramolecular reaction of this ion to form an acetoxonium ion (14), the reaction with an alcohol yields the orthoester (e.g.1-7). In a similar manner, and in concurrence with direct glycosylation, ortho esters and products arising from orthoesters may be formed in the usual glycoside synthesis, using the reaction just described with the solvent or other nucleophiles.     

Flavonoid glycosides and a bitter principle from lomatogonium carinthiacum

Three flavone glycosides, including the novel 6-hydroxyluteolin 7-O-gentiobioside, and a bitter secoiridoid glycoside, swertiamarin, have been identified in the aerial parts of Lomatogonium carinthiacum. Four minor xanthone glycosides were also detected. Separations were made with droplet counter-current chromatography (DCCC) in combination with column chromatography. Structure elucidation was achieved by UV, ¹H and ¹³C NMR, FDMS and D/CIMS spectra.     

Isolation of glucosinolates and the identification of o-(α-l-rhamnopyranosyloxy)benzylglucosinolate from Reseda odorata

A method has been developed for the quantitative isolation of glucosinolates by ion-exchange chromatography and high voltage electrophoresis avoiding strongly alkaline and acidic conditions. The compounds were identified by ¹H and ¹³C NMR spectroscopy and through the products arising from enzymatic, acid and alkaline hydrolysis. The method is well suited for the isolation and identification of glucosinolates containing aglucone parts which produce non-volatile compounds on enzymatic hydrolysis. The method has been used in the isolation and identification of 2-hydroxy-2-methylpropylglucosinolate from Reseda alba, 2-hydroxy-2-phenylethylglucosinolate from R. luteola and a new glucosinolate, o-(α-l-rhamnopyranosyloxy)benzylglucosinolate, occurring in R. odorata. The glucosinolate content in different parts of this plant has been determined and the metabolism of glucosinolates is briefly discussed.     

Two new dihydrochalcones from Myrica gale

From the fruits of Myrica gale the isolation of 2′,6′dihydroxy-4′-methoxy-3′,5′-dimethyldihydrochalcone and 4,4,6-trimethyl-2-(3-phenylpropionyl)-cyclohexane-1,3,5-trione is described. The constitutions have been deduced from spectroscopic data and confirmed by synthesis.     

Determination of cytokinins by mass spectrometry based on stable isotope dilution.

A method for quantitative determination of individual cytokinin species has been developed, based on gas chromatography-mass spectrometry and selected ion monitoring. Deuterated internal standards were prepared for analysis of N⁶-isopentenyladenosine, N⁶-isopentenyl-2-methylthioadenosine, zeatin riboside, and 2-methylthiozeatin riboside and were tested over the range of 1 to 20 ng of endogenous cytokinin per injection, relative to 100 ng of labeled standard. An isolation procedure for extracts of cabbage hearts as a model plant source has been developed that gives maximum recovery and minimum interference for gas chromatographic-mass spectrometric measurements. The present method differs from the commonly used bioassay by its selectivity for individual cytokinin components and shortened analysis time, including extractions, of 3 days vs several weeks.     

Proacaciberin,A cyanogenic glycoside from Acacia sieberiana var. Woodii

A new cyanogenic glycoside isolated from pods of Acacia sieberiana var. woodii has been shown by chemical and spectroscopic methods to be (2S)-2-[(6-O-α-l-arabinopyranosyl-β-d-glucopyranosyl)oxy]-3-methylbut-3-enenitrileo. Acid-catalysed hydrolysis of the glycoside afforded arabinose and proacacipetalin, and base-catalysed double-bond migration gave 2- [(6-O-α-l-arabinopyranosyl-β- d-glucopyranosyl)oxy ]-3-methylbut-2-enenitrile.     

Quercetin 3-glucosylgalactoside from pollen of Corylus avellana

The main flavonoid glycoside from the pollen of Corylus avellana has been characterized as quercetin 3-O-(2″-O-β-d-glucopyranosyl)-β-d-galactopyranoside on the basis of UV, ¹H NMR, ¹³C NMR and mass spectral data and GLC sugar analysis.     

3′-Hydroxypsilotin,a minor phenolic glycoside from Psilotum nudum

A new non-flavonoid glycoside, 3′-hydroxypsilotin {6-[4′-(β-D-glucopyranosyloxy)-3′-hydroxyphenyl]-5,6-dihydro-2-oxo-2H-pyran}, was isolated from Psilotum nudum by droplet counter current chromatography and preparative HPLC. The structure was established by spectroscopic analysis including ¹H and ¹³C NMR and high resolution mass spectrometry.     

Elucidation of structure and biosynthesis of acacipetalin

The structure of acacipetalin isolated from Acacia sieberiana var. woodii has been revised, primarily on the basis of NMR spectra. Biosynthetic studies on the compound show that l-leucine is the most effective precursor of the aglycone. The isolation of a second cyanogenic glycoside closely related to acacipetalin is reported.