bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraction of purine alkaloids from cocoa tissues and determination by high‐performance liquid chromatography
Authors: Gurney Kären A. , Evans L. V. , Robinson David S.
Published: March 2007

Protocols for the extraction and quantification by high‐performance liquid chromatography of purine alkaloids from cocoa beans, Theobroma cacao plants and tissues cultivated in vitro have been developed. These allow the rapid determination of 7‐methylxanthine, 3‐dimethylxanthines and caffeine from complex mixtures and represent improvements over published methods. Alkaloids were extracted in boiling water and the extracts clarified by precipitation and filtration. Chromatography was carried out using C18 reverse‐phase columns with isocratic elution. The eluate was monitored routinely at 280 nm and compounds quantified using external standards. Estimations of purine alkaloid recoveries were better than 98% for caffeine, theobromine and theophylline. Reproducibility of replicate injections averaged 99% with coefficients of variation between replicate extractions typically less than 5% except for small samples (i.e., less than 0.2 g dry weight). Results for cocoa nibs and shells; roots, stem, green and red leaves of the cocoa plant; callus and suspension‐cultured cells and growth media from one type of cocoa are reported.
Selective INEPT spectroscopy–‐A powerful tool for the spectral assignment and structure elucidation of natural products
Authors: Cordell Geoffrey A.
Published: March 2007

The one‐dimensional, J‐modified, proton‐carbon correlation technique, known as the selective INEPT technique, has proved to be a powerful tool for both unambiguous carbon and proton spectral assignment and also provides critical carbon framework information.
Carbonic anhydrase catalysed hydrolysis of fluorogenic esterase substrates
Authors: Cohen Jason D. , Husic H. David
Published: March 2007

Carbonic anhydrases from spinach leaves, Chlamydomonas reinhardtii and bovine erythrocytes were examined for their ability to hydrolyse the fluorogenic esterase substrates 7‐acetoxy‐4‐methylcoumarin, 7‐acetoxycoumarin‐3‐carboxylic acid and fluorescein diacetate. The spinach enzyme was unable to hydrolyse any of the three substrates, however, the C. reinhardtii enzyme hydrolysed 7‐acetoxy‐4‐methylcoumarin and fluorescein diacetate, but at a much slower rate than the bovine erythrocyte enzyme which hydrolysed all three substrates. A method was developed to assay purified carbonic anhydrase from C. reinhardtii based on the enzyme‐catalysed hydrolysis of fluorescein diacetate.
Use of evaporative light scattering mass detection in high performance liquid chromatography of triterpenes in the bark resin of betula species
Authors: Taipale Hannu T. , Lapinjoki Seppo P.
Published: March 2007

Plants often contain triterpenes that are difficult to analyse by high performance liquid chromatography (HPLC) due to lack of double bonds or other chromophores that can be readily detected spectrophotometrically. The present results show that light scattering mass detection (LS) is useful in such cases. We have been able to replace thin layer chromatography (TLC) with HPLC by using LS in evaluating triterpene contents in the bark resin of different birches (Betula pendula Roth., B. resinifera (Regel) Fern. & Raup., B. platyphylla Sucachev, B. ermanii Cham., B. papyrifera Marsh and B. pubescens Ehrh.). LS was five‐fold more sensitive than UV for papyriferic acid, which was used as a reference compound, and HPLC/LS revealed new compounds and qualitative relations that were undetectable by UV or TLC. This paper describes detection of a new major triterpenoid from B. pendula, the age dependency of the triterpenoid content in B. pendula and B. papyrifera and gives an interspecies comparison of the triterpenoid content of the different species.
Application of on‐line HRGC‐FTIR spectroscopy to the analysis of acetylenic flavour precursors
Authors: Winterhalter Peter , Full Gerhard , Herderich Markus , Schreier Peter
Published: March 2007

Aroma extracts from various plants were screened for acetylenic flavour precursors using on‐line HRGC‐FTIR spectroscopy. Selected wavelength monitoring (2100–2250 cm−1) revealed for the first time the presence of 3‐hydroxy‐7,8‐didehydro‐β‐ionone in peelings of lulo syn. naranjilla (Solanum vestissimum D.) fruit. The same compound was also detected as a major aglycone after enzymatic hydrolysis of a glycosidic extract isolated from Vitis vinifera cv. Riesling leaves. The related acetylenic diol, 3‐hydroxy‐7,8‐didehydro‐β‐ionol, was similarly identified as the aglycone in a glycosidic extract obtained from purple passion fruit (Passiflora edulis Sims) juice. The discovery of these acetylenes is discussed with regard to the formation of β‐damascenone in plants.
Quantitative enzyme cytochemistry in plant biotechnology
Authors: Gahan P. B.
Published: March 2007

Immunocytochemistry, one of the two basic approaches to the in situ study of enzymes, allows the enzyme molecules to be localized, but indicates nothing about their activity. Quantitative cytochemistry, on the other hand, indicates the sites of localization of enzyme activity and, in many cases, the rates of these activities. This latter approach, which is the subject of this review, permits the assessment of activity in individual cells or groups of cells in a given tissue. Details of tissue preparation, enzyme procedures, methods of quantification and some case histories illustrate the specificity and flexibility of the method.
Unambiguous nuclear magnetic resonance assignments for swainsonine, an indolizidine alkaloid with α‐mannosidase inhibitory activity
Authors: Kardono Leonardus B. S. , Kinghorn A. Douglas , Molyneux Russell J.
Published: March 2007

The proton and carbon‐13 nuclear magnetic resonance (NMR) spectra of swainsonine, (1S,2R,8R,8R,8aR)‐1,2,8‐trihydroxyoctahydroindolizine, isolated from the seeds of Astragalus oxyphysus A. Gray, have been reassigned through the use of two‐dimensional NMR techniques. Unambiguous NMR spectral data have also been determined for swainsonine 1,2,8‐triacetate.
Separation of iridoids by vacuum liquid chromatography
Authors: Handjieva Nedjalka , Saadi Houcine , Popov Simeon , Baranovska Iskra
Published: March 2007

Vacuum liquid chromatography (VLC) was used for the separation of iridoids isolated from Valeriana officinalis L. and Centranthus ruber D. C. (Valerianaceae), Plantago media L. (Plantaginaceaea), Viburnum lantana L. (Caprifoliaceae), Gentiana punctata L. and Erythraea centaurium Pers. (Gentianaceae). The advantages of the technique over preparative thin layer chromatography and open‐column chromatography are discussed. Decapetaloside was isolated from V. lantana for the first time as were sweroside and swertiamarin from G. punctata. Florisil was used for the first time as an adsorbent for VLC.
Investigation of extracts of plant cell cultures by proton nuclear magnetic resonance spectroscopy
Authors: Schripsema Jan , Verpoorte Robert
Published: March 2007

A method for the rapid phytochemical characterization of plant cell cultures, using proton nuclear magnetic resonance spectroscopy (1H NMR), is described. Aqueous extracts were prepared from a large number of plant cell suspension cultures. Following lyophilization, the extracts were redissolved in D2O containing an internal standard to enable quantification and 1H NMR spectra were measured. In the spectra, signals from sugars and amino acids were observed. The patterns obtained were characteristic of cell lines, with related lines typically showing similar characteristics, e.g., Tabernaemontana suspension cultures are characterized by their ability to accumulate large amounts of arginine, while Catharanthus cultures mainly accumulate glutamine. The amounts of amino acids accumulated were found to be determined mainly by the medium on which the cell cultures were growing. Murashige and Skoog medium supported nitrogen storage in amino acids, while Gamborg B5 medium did not. Reference spectra of some of the most common constituents are presented, together with data enabling a direct quantification of these compounds in aqueous extracts.
Multidimensional gas chromatography/mass spectrometry: A powerful tool for the direct chiral evaluation of aroma compounds in plant tissues. II. Linalool in essential oils and fruits
Authors: Bernreuther Alexander , Schreierc Peter
Published: March 2007

On‐line coupled multidimensional gas chromatography (DB‐5/Lipodex C)/mass spectrometry was used for direct chiral analysis of linalool in 15 essential oils and 16 fruit species. Whereas in a number of commercial essential oils racemic linalool was found, in the corresponding oils prepared in the laboratory enantioselective distribution of linalool was determined. Among the fruits studied, (R)‐(−)‐linalool dominated in guava, greengage, lulo (Solanum vestissimum), peach and plum. In arctic bramble, mango, yellow passion fruit, raspberry and strawberry the (S)‐(+)‐enantiomer prevailed. The occurrence of approximately racemic linalool was established in apricot [(enantiomeric excess (ee) 6.0% (R)], mirabelle plum [ee 9.4%(R)], red passion fruit [ee 9.0% (R)] and pineapple [ee 6.6% (R)].
Structure elucidation of cyanidin‐3‐sambubioside and assignments of the 1H and 13C NMR resonances through two‐dimensional shift‐correlated NMR techniques
Authors: Andersen Øyvind M. , Aksnes Dagfinn W. , Nerdal Willy , Johansen Ole‐P.
Published: March 2007

The anthocyanin cyanidin‐3‐sambubioside was isolated from the acidified methanolic extract of the fruits of Sambucus nigra by successive application of an ion exchange resin, droplet countercurrent chromatography and gel filtration. By means of chemical degradation and spectroscopy (especially one‐ and two‐dimensional NMR techniques) the structure has been determined to be cyanidin‐3‐O‐β‐D‐xylopyranosyl‐(1±2)‐β‐D‐glucopyranoside with both the sugar rings assuming a 4C1 chair conformation.

The combination of several NMR techniques such as double‐quantum filtered proton‐proton shift correlation (DQF‐COSY), homonuclear Overhauser enhancement (NOE) difference spectroscopy, heteronuclear coupling‐modulated spin echo, proton‐carbon shift correlation optimized for direct (HSC) and long‐range coupling (COLOC) provided assignments of the 1H and 13C signals. The coupling constants of the sugar protons were obtained by iterative spin simulation. This is the first report of a heteronuclear shift correlation experiment applied on anthocyanins.
Determination of cyclic 3′,5′‐adenosine monophosphate in plant tissues by high performance liquid chromatography
Authors: Yavorskaya V. K. , Dragovoz I. V. , Savinsky S. V. , Markova V. E. , Sh. Kofman I.
Published: March 2007

A quantitative method has been developed for determining cyclic 3′,5′‐adenosine monophosphate (cAMP) in plant tissues based on the use of high performance liquid chromatography following partial purification of cyclonucleotides from plant extracts by different chromatographic procedures. The identical nature of a plant cAMP‐like substance and synthetic cAMP has been demonstrated. The lower limit of cAMP detection was 2.6 ng, the overall efficiency of determination was 34.0% and the standard deviation was ±5.2%. The concentration of cAMP in rye seedlings was determined to be 0.700±0.069 n mol per g fresh weight of tissue.
Quantitative determination by high performance liquid chromatography and microspectro‐fluorimetry of phenolic acids in maize grain
Authors: Sen A. , Miller S. S. , Arnason J. T. , Fulcher R. G.
Published: March 2007

A method for improved recoveries of phenolic acids in maize grain extracts and their quantification by high performance liquid chromatography (HPLC) is described. A quantitative imaging technique to determine mean ferulic acid autofluorescence of ground grain samples was found to be correlated (r=0.86, n=14, P=0.05) with HPLC analysis of ferulic acid in a wide range of different maize genotypes. The advantage of the imaging method is that it reduces procedures required and analysis time considerably.
Structure of petanin, an acylated anthocyanin isolated from solanum tuberosum, using homo‐and hetero‐nuclear two‐dimensional nuclear magnetic resonance techniques
Authors: Andersen Øyvind M. , Opheim Sigrid , Aksnes Dagfinn W. , Frøystein Nils Åge
Published: March 2007

The anthocyanin, petanin, was isolated from the acidified methanolic extracts of blue tubers of the potato (Solanum tuberosum) by successive application of ion exchange chromatography, droplet counter‐current chromatography and gel filtration. The full structure, petunidin 3‐O‐[6‐O‐(4‐O‐E‐p‐coumaroyl‐α‐L‐rhamnopyranosyl)‐β‐D‐glucopyranoside]‐5‐O‐β‐D‐glucopyranoside, with both the glucopyranose rings assuming a4C1 chair conformation and the rhamnopyranose ring assuming a 1C4 chair conformation, was elucidated by means of chemical degradation, chromatography and spectroscopy, especially homo‐ and hetero‐nuclear two‐dimensional nuclear magnetic resonance techniques.
The determination of double bond positions in polyunsaturated fatty acids–‐Gas chromatography/mass spectrometry of the diethylamide derivative
Authors: Nilsson Ralf , Liljenberg Conny
Published: March 2007

Diethylamides were prepared from polyunsaturated long‐chain fatty acids and were examined by gas chromatography/mass spectrometry. The spectra contained informative ions which allowed immediate recognition of the position of the original double bonds. The derivatives were easily prepared in one step and were baseline‐separated on the gas chromatographic column at moderate temperatures. This method was suitable for samples of long‐chain fatty acid mixtures.
Multidimensional gas chromatography/mass spectrometry (MDGC/MS): A powerful tool for the direct chiral evaluation of aroma compounds in plant tissues. III. (1S)‐(–‐)‐2‐endo‐Acetoxy‐3‐exo‐hydroxybornane (vulgarole) in mugwort (Artemisia vulgaris L.) herb
Authors: Wörner Martin , Schreier Peter
Published: March 2007

On‐line coupled multidimensional gas chromatography (DB‐5/Lipodex D)/mass spectrometry (MDGC/MS) revealed the occurrence of (1S)‐(–‐)‐2‐endo‐acetoxy‐3‐exo‐hydroxybornane (vulgarole) with 100% enantiomeric excess in mugwort (Artemisia vulgaris L.) herb. The result was verified by means of synthesized optically pure (1R) and (1S) enantiomers of vulgarole.
A high performance liquid chromatographic procedure for the analysis of tobacco alkaloids‐‐Application to the evaluation of tobacco alkaloids in plants and cell suspension cultures
Authors: Manceau Francoise , Fliniaux Marc‐Andre , Jacquin‐Dubreuil Annie
Published: March 2007

A high performance liquid chromatographic (HPLC) procedure for the analysis of tobacco alkaloids in plant material is described. It allows the detection of up to 10 ng of nicotine, nornicotine, anabasine and nicotinic acid. It is more efficient with regard to the sensitivity, simplicity and suitability for phytochemical analysis than the gas chromatographic (GC) procedure previously used by the authors. Alkaloid extraction and purification prior to HPLC analysis can be carried out more quickly and easily. The method has been applied to the study of the bioconversion of nicotine into nornicotine by Nicotiana plumbaginifolia cell suspensions. The yield of biotransformation which was estimated at 53.2% by GC analysis is now found to be nearly 100% by HPLC analysis. Moreover, it has been shown that the method is reliable for the evaluation of high or low quantities of endogenous alkaloids produced by plant organs or tissue cultures.
The enhanced role of a lanthanide shift reagent in the structure elucidation and 1H NMR and 13C NMR characterization of some marine natural products
Authors: Wright Anthony D. , König Gabriele M. , Sticher Otto
Published: March 2007

Three marine‐derived natural products, 1, 2 and 3, were used to demonstrate the enhanced role of a lanthanide shift reagent [Europium(III)‐tris(1,1,1,2,2,3,3)‐heptafluoro‐7,7‐dimethyl‐d6‐octa‐4,6‐dion‐d3, C30H3D27EuF21O6, (Eu(fod)3)] in the structure elucidation of compounds containing a single hydroxyl function. The value of reagents of this type, both as an aid to structure solution as well as in the complete assignment of 1H NMR and 13C NMR resonances, is clearly demonstrated as a consequence of the development of proton‐detected proton‐carbon correlated 2D‐NMR methodologies.
A new chromatographic method for the isolation of (−)‐Δ9‐(trans)‐tetrahydrocannabinolic acid A
Authors: Lehmann T. , Brenneisen R.
Published: March 2007

(−)‐Δ9‐(trans)‐Tetrahydrocannabinolic acid A (THCA‐A), which is the main cannabinoid in ripe plants and the biogenetk precursor of the psychoactive (−)‐Δ9‐(trans)‐tetrahydrocannabinol, has been isolated from Cannabis sativa L. After extraction with petroleum ether and subsequent fractionation using alkali and diethyl ether, purification was performed by medium pressure liquid chromatography to yield an amorphous >99% pure powder. THCA‐A was characterized by its chromatographic and spectroscopic data.
Rapid screening assay of cyanide content of cassava
Authors: Bradbury J. Howard , Egan Sylvia V.
Published: March 2007

A rapid, inexpensive screening assay was developed in order to measure the cyanide content of cassava (Manihot esculenta Crantz) tubers. A small disc of parenchyma tissue cut with a cork borer or alternatively grated tissue was placed in a stoppered glass tube and the hydrogen cyanide liberated produced a blue colour on a filter paper previously spotted with a drop of tetra‐base [4,4'‐methylenebis‐(N,N‐dimethylaniline)] and cupric acetate. The intensity of the blue colour which developed within one hour was rated visually on a graded scale from 0 to 5. The correlation coefficient between samples accurately analysed for total cyanide and also tested using the rapid assay was 0.77.
Assay of the thiobarbituric acid‐reactive products of lipid peroxidation in plants using derivative absorption spectroscopy
Authors: Merzlyak Mark N. , Zhigalova Tatyana V. , Shevyryova Varvara V.
Published: March 2007

The spectrophotometric determination of 2‐thiobarbituric acid‐reactive products of lipid peroxidation in plants is limited because of the presence of substances forming coloured complexes with the reagent as well as water‐soluble pigments. In order to overcome this interference 2nd derivative analysis of the absorption spectra was applied. The results of the study indicate that the method can be performed using cotton and maple leaves that contain high amounts of anthocyanins and bifunctional aldehydes, respectively. The accumulation of lipid peroxidation products was observed in cotton plants treated with the herbicide diquat. In wheat roots the band of malondialdehyde‐thiobarbituric acid absorption was not resolved either in intact or in diquat‐treated plants, because of the production of a chromophore with an absorption maximum at 551 nm. The sensitivity of the 2nd derivative determination of malondialdehyde is about 0.2 μ. A linear response was observed up to 8–10 μ of the aldehyde.
Quantitative analysis of serpentine and ajmalicine in plant tissues of Catharanthus roseus and hyoscyamine and scopolamine in root tissues of Datura stramonium by thin layer chromatography‐densitometry
Authors: Monforte‐González M. , Ayora‐Talavera T. , Maldonado‐Mendoza I. E. , Loyola‐Vargas V. M.
Published: March 2007

Sensitive and rapid thin layer chromatographic‐densitometric methods have been developed for the quantification of the indole alkaloids, ajmalicine and serpentine, and of the tropane alkaloids, hyosycamine and scopolamine. The concentration ranges in which accurate and reproducible results can be obtained are 1‐8 μg for the tropane alkaloids, 1‐10 μg for ajmalicine and 200–1400 ng for serpentine. The limit of detection for serpentine is 20 ng and 500 ng for the other alkaloids. The methods have been successfully employed for the determination of alkaloids in tumours and calli of Catharanthus roseus, in root tissues of Datura stramonium and also in the respective liquid culture media.
Extraction and biossay‐directed fractionation of the cytotoxic metabolites from Chelidonium majus
Authors: De Giulio A. , De Rosa S. , Di Vincenzo G. , Strazzullo G.
Published: March 2007

An exhaustive extraction model and a general adsorption chromatographic method involving a rapid stepgradient are described for the initial fractionation of weakly‐ and non‐polar fractions from Chelidonium majus L. Fractionation and purification of cytotoxic metabolites were directed by bioassay using the Artemia salina test.
A rapid quantitative method for the analysis of sesquiterpene phytoalexins by high performance liquid chromatography
Authors: Moreau Robert A. , Preisig Carol L. , Osman Stanley F.
Published: March 2007

A new high performance liquid chromatographic technique has been developed for the rapid analysis of sesquiterpene phytoalexins such as capsidiol, rishitin, lubimin and phytuberol. This method employs a cyanopropyl‐bonded phase column with an isocractic mixture of hexane and isopropanol. When used with a flame ionization detector the lower limits of detection are about 0.1 μg and the response of the detector is linear in the range 0.1–30 μg. With the UV detector at 205 nm, the lower limits of detection are about 0.1 μg for capsidiol and rishitin and 0.5 μg for lubimin, phytuberol and debneyol. The response of the UV detector is linear in the range 0.5–30 μg. Although both detectors proved to be useful, the signal response with the flame ionization detector was proportional to the mass of each of the phytoalexins, while the signal with the UV detector was proportional to the number of carbon‐carbon double bonds in each of the compounds.
Standardization of the indian crude drug kalmegh by high pressure liquid chromatographic determination of andrographolide
Authors: Sharma Anupam , Lal Krishan , Handa Sukhdev S.
Published: March 2007

The popular hepatoprotective Indian herbal drug Kalmegh (Andrographis paniculata) can be standardized by high pressure liquid chromatographic determination of its major active constituent, andrographolide. The leaves of the herb were found to contain the highest amount (2.39%w/w) of andrographolide and the seeds to contain the lowest. The technique was found to be much more sensitive and simple than the known spectrophotometric method.
The analysis of phytoecdysteroids in single (preflowering stage) specimens of fat hen, Chenopodium album
Authors: Dinan Laurence
Published: March 2007

A simple microextraction procedure together with an ecdysteroid‐specific radioimmunoassay (RIA) have been used to quantify the levels of phytoecdysteroid in small (<50 mg dry wt.) samples of plant tissues during the development of Chenopodium album. The existence of a distinct concentration gradient of phytoecdysteroids within the aerial portions has been confirmed by the detailed analysis of ecdysteroid titres throughout single plants. Ecdysteroid concentration increased steadily up the main stem of the plant. This pattern was reflected in the main leaves and in the petioles associated with the main leaves. The ecdysteroid concentration in the growing tip was higher than those at the top of the stem or in the uppermost leaves. High concentrations were also present in the roots. The distinct concentration gradient characteristic of the main stem, associated leaves and growing tip recurred in each of the side‐shoots on a mature plant. The identity of the RIA‐positive material is essentially identical in most parts of the plant, being mainly 20‐hydroxyecdysone (20OHE) and polypodine B (PolB; 5β,20‐dihydroxyecdysone) with much smaller amounts of more polar and less polar unidentified compounds. In the oldest leaves, the contribution of 20OHE and PolB is reduced and new polar and apolar compounds are found, indicating that catabolism of phytoecdysteroids occurs as leaves begin to senesce.
Computer‐assisted elucidation of structures of natural products
Authors: Massiot G. , Nuzillard J. M.
Published: March 2007

An historical survey of the first computer programs capable of handling spectroscopic data and of transforming them into possible molecular structures is exemplified by some applications. Technological improvements of nuclear magnetic resonance spectroscopy now allow the direct collection of connectivity relationships between atoms, and the integration of this new kind of spectroscopic data by “intelligent” computer programs is demonstrated by the resolution of practical problems for which human expertise would not be straightforward.
Intermolecular aromatic acid association of an anthocyanin (petanin) evidenced by two‐dimensional nuclear overhauser enhancement nuclear magnetic resonance experiments and distance geometry calculations
Authors: Nerdal Willy , Andersen Øyvind M.
Published: March 2007

A new mechanism is described for intermolecular association of the aromatic acid of the anthocyanin petanin (petunidin 3‐O‐[6‐O‐(4‐O‐E‐p‐coumaroyl‐α‐L‐rhamnopyranosyl)‐β‐D‐glucopyranoside]‐5‐0‐β‐D‐glucopyrano‐side) in cold solution. Petanin was studied in acidified methanolic solution using the nuclear Overhauser enhancement (NOESY) nuclear magnetic resonance technique at −5° and –20°C. Inter‐ and intra‐molecular coumaroyl group NOESY cross‐peaks were observed, and the corresponding proton‐proton distance bounds were used in distance geometry calculations to determine the association of the coumaroyl groups. The orientation of two associated petanin coumaroyl groups was found to be head‐to‐tail along the long coumaroyl group axis. The corresponding orientation along the short coumaroyl group axis could not be determined conclusively; however, the most probable orientation is head‐to‐head. Lack of observed NOESY cross‐peaks between protons of the coumaroyl group and the aglycone indicated absence of the intramolecular coumaroyl group‐aglycone association which has been suggested for other acylated anthocyanins. A structure for a petanin dimer is suggested.
Characterization of honeysuckle (Lonicéra caprifolium L.) seed oil triacylglycerols by high performance liquid chromatography and light scattering detection
Authors: Bergqvist Magnus H. J. , Olsson N. Urban
Published: March 2007

A method is described which utilizes solvent extraction and preparative thin layer chromatography to isolate triacylglycerols from the seeds of the Genuine Honeysuckle (Lonicéra caprifolium L.). Preparative liquid chromatography in conjunction with gas chromatography and high performance liquid chromatography with light‐scattering detection were further used to characterize the pattern of molecular species of the triacylglycerols.
High performance liquid chromatography of zanhic acid glycoside in alfalfa (Medicago sativa)
Authors: Nowacka J. , Oleszek W.
Published: March 2007

The aerial parts of alfalfa (Medicago sativa L.) contain a considerable amount of zanhic acid tridesmoside which, due to its low activity, cannot be determined using standard biological procedures. A high performance liquid chromatographic method has been developed for its determination. The procedure employs the alkaline hydrolysis of the tridesmoside followed by the derivatization of released prosapogenins with 4‐bromophenacyl bromide. It is demonstrated that alkaline hydrolysis of tridesmoside generates different prosapogenins depending on the solvent used. The conditions for alkaline hydrolysis has been optimised.
A comparative study of two spectrophotometric methods for measuring coniferyl alcohol oxidation catalysed by peroxidase
Authors: Calderón A. A. , Munoz R. , Morales M. , Barceló A. Ros
Published: March 2007

Two spectrophotometric methods for measuring coniferyl alcohol (CA) oxidation catalysed by peroxidases are compared on the basis of their sensitivity, detection limit and validity for kinetic purposes. Measurement of the absorbance changes in the UV region (260 nm) is much better than evaluation in the visible range (620 nm), since the UV changes monitor the disappearance of CA in reaction media, while the VIS changes measure the appearance of lignin‐like products, which may not be kinetically correlated with CA oxidation. In addition, UV measurements are more sensitive and their detection limit is lower.
The determination of catecholamines in Crataegus oxyacantha L. Flowers and leaves by high pressure liquid chromatography‐electrochemical detection
Authors: Saija A. , Germano M. P. , Marzullo D. , Imperatore C. , Campo S. , De Pasquale R.
Published: March 2007

A combined extraction system for the selective and quantitative determination of the monoamines noradrenaline, adrenaline, dopamine and L‐DOPA from the flowers and leaves of Crataegus oxyacantha L. has been developed. The method is based on a preliminary isolation of monoamines by successive petroleum ether and chloroform clean‐up, absorption on alumina and passage through Sep‐Pak C18 cartridges, followed by measurement of the catecholamines by high pressure liquid chromatography, with electrochemical detection, on a reversed phase column. The described method appears sufficiently simple, sensitive, precise and accurate for routine use and holds great promise for pharmacognostic studies.
The application of two‐dimensional nuclear magnetic resonance methodologies to the structure solution of the new natural product tenerol acetate from Laurencia tenera
Authors: Wright Anthony D. , König Gabriele M. , Sticher Otto , Rüegger Heinz
Published: March 2007

From the marine red alga Laurencia tenera the new metabolite (1R.
Normal phase liquid chromatographic analysis of toxic norditerpenoid alkaloids
Authors: Manners Gary D. , Pfister James A.
Published: March 2007

A normal phase, isocratic, analytical high performance liquid chromatographic (HPLC) method has been developed for the analysis of toxic methylsuccinimidoanthranoyllycoctonine (MSAL) norditerpenoid alkaloids occurring in poisonous larkspurs (Delphinium sp.). The method has good sensitivity, specificity for MSAL norditerpenoid alkaloid and rapid analysis times. The technique employs 5 μm neutral alumina as the stationary phase and utilizes a mixture of hexane: 95% isopropyl alcohol as the mobile phase. Accurate and reproducible analyses can be performed on 1 g samples of plant material. The method has been applied to the analysis of the chemical phenology of the MSAL norditerpenoid alkaloids methyllycaconitine and 14‐deacetylnudicauline in three species of tall larkspurs (Delphinium barbeyi, D. occidentale, D. glaucescens). Analytical results confirm the primary occurrence of these toxic alkaloids in early vegetative tissues of these plants, their concentration in reproductive plant tissues and their reduction in level with plant maturation. The chemical phenology results further confirm the observed difference in the toxicity of the three tall larkspurs (D. barbeyi > D. glaucescens > D. occidentale) to livestock. Intraspecies differences of toxic alkaloid occurrence associated with site were also demonstrated.
Annonaceous acetogenins: An updated review
Authors: Fang Xin‐Ping , Rieser Matthew J. , Gu Zhe‐Ming , Zhao Geng‐Xian , McLaughlin Jerry L.
Published: March 2007

The Annonaceous acetogenins are an exciting new class of bioactive natural products whose antitumour, pesticidal and other bioactivities are due to inhibition of electron transport in mitochondria. This paper tabulates the 61 compounds in this class which have been published in the period of 1990–1992 and reviews recent progress with the chemistry and biology of these potent compounds. (Appendices will be published in the next issue.)
Microassay to measure phytoalexin response in protoplasts of bean leaves
Authors: Soriano Eva , García Ernesto
Published: March 2007

Phytoalexins are secondary metabolites that in legumes are typically isoflavonoid derivatives. Techniques for their measurement very often use determination of the UV absorbance of ethanol extracts to avoid time‐consuming extractions and the use of expensive solvents. However, other phenolic compounds also give UV absorbances interfering with quantitative determinations. A microassay is proposed to extract and measure bean phytoalexins from intact, viable, bean leaf protoplasts. Protoplasts as a tool for measuring phytoalexin elicitor stimulation is discussed.
Reverse‐phase high pressure liquid chromatographic analysis of hydroxycoumarins in plant extracts. Quantitative determination of hydroxycoumarins in Fraxinus ornus
Authors: Nykolov Nykolay , Iossifova Tanya , Vassileva Elka , Kostova Ivanka , Stoev Georgi
Published: March 2007

A reverse‐phase high pressure liquid chromatographic determination of 11 hydroxycoumarins in plant extracts is described, which is applicable to the quantitative analysis of these compounds for industrial purposes. Fraxinus ornus bark from various regions in Bulgaria showed differences both in the total coumarin content and in the relative proportions of each component. The occurrence of 7‐methylesculin and 6,7,8‐trihydroxycoumarin in the family Oleaceae is reported for the first time.
Biosynthetic relationship of aromoline and berbamine in cultured roots of Stephania cepharantha
Authors: Sugimoto Yukihiro , Kawaminami Shunro , Yamada Yasuyuki
Published: March 2007

Cultured roots of Stephania cepharantha, rich in the bisbenzylisoquinolines aromoline (1) and berbamine (2), were fed [3‐13 C]tyrosine. The labelled alkaloids were isolated. 13C NMR spectra showed that 13C was specifically incorporated into sites on 1 and 2. The ratios of 13C enrichment for the benzyl and isoquinoline portions of 1 and 2 were the same within the experimental limits, evidence that both alkaloids are derived from a common intermediate.
Qualitative and quantitative determination of taxol and related compounds in Taxus cuspidata Sieb et Zucc
Authors: Fang Weishuo , Wu Yue , Zhou Jinyun , Chen Weiming , Fang Qicheng
Published: March 2007

In this paper the determination of taxol and the related compounds 10‐deacetyltaxol, cephalomannine and 10‐deacetylcephalomannine in various parts of Taxus cuspidata Sieb et Zucc. is reported. All four compounds were well separated on a 5 μm Spheri‐5 RP‐18 column with a mobile phase composed of water:acetonitrile:tetra‐hydrofuran (55:35:10). The concentrations of these compounds are quite different for different parts of the plant and are highest in stem bark. Furthermore, the content is related to the age of the plant, the older plants containing larger quantities of taxane diterpenoids. We have also found that the contents of taxol and related compounds in the shrub are usually higher than those in the tree.
Determination of cinnamic acid and 4‐coumaric acid in alfalfa (Medicago sativa L.) cell suspension cultures by gas chromatography
Authors: Orr John D. , Sumner Lloyd W. , Edwards Robert , Dixon Richard A.
Published: March 2007

A capillary gas chromatographic (GC) method for the assay of cinnamic acid and 4‐coumaric acid in alfalfa (Medicago sativa L.) cell extracts is described. These compounds were assayed as their trimethylsilyl derivatives; hydrocinnamic acid was used as the internal standard for quantifications. This method was qualitatively validated by GC/mass spectral analysis and quantitatively validated by measuring the extraction recovery from alfalfa cells, the recovery from derivatization, the stability of silylated derivatives, the limits of detection, the linearity of the detector response to increasing amounts of analytes, and the intra‐ and inter‐assay precisions. Cinnamic acid and 4‐coumaric acid were present in alfalfa cell extracts and were resolved from all other components by this method. As little as 4 pmol of each acid could be quantified, and the detector response was linear over a range covering five orders of magnitude. The cellular concentrations of free cinnamic acid and 4‐coumaric acid ranged from ca. 5–100 μmol/kg fresh weight tissue.
Measurement of latent polyphenol oxidase activity in the presence of the divalent cations Ca+2, Mg+2 and Mn+2
Authors: Jiménez Mercedes , García‐Carmona Francisco
Published: March 2007

In the present paper the specific effect of divalent cations on the measurement of the catecholase activity of latent polyphenol oxidase, extracted from Gamay grape suspension cultures, is analysed. The optimum conditions for the activation process produced by the divalent cations have been examined with respect to cation concentration and the pH of the reaction medium. This activation has also been studied with regard to the kinetic parameters of the enzyme in its catalytic expression on 4‐methylcatechol. In order to maximize the catalytic capacity of latent polyphenol oxidase it is necessary to measure the enzymic activity in the presence of divalent cations such as Ca+2, Mn+2 or Mg+2.
The application of thermal desorption‐gas chromatography‐mass spectrometry to the analyses of flower volatiles from five varieties of oilseed rape (Brassica napus spp. oleiferd)
Authors: Robertson G. W. , Griffiths D. W. , Smith W. MacFarlane , Butcher R. D.
Published: March 2007

Thermal desorption coupled to capillary gas chromatography‐mass spectrometry has been used to identify volatile chemicals released from the flowers of five varieties of oilseed rape. An entrainment apparatus for volatile headspace analysis is described. The major classes of compound found were organic sulphides, C4 substituted compounds, aldehydes and terpenes. The possible role of these compounds in the human allergic‐type response associated with oilseed rape is discussed.
Selective extraction of phenolic components from Ginkgo biloba extracts using supercritical carbon dioxide and off‐line capillary gas chromatography/mass spectrometry
Authors: Verotta Luisella , Peterlongo Federico
Published: March 2007

A method has been developed for the extraction and analysis of phenolic components from crude extracts of Ginkgo biloba by supercritical fluid extraction with carbon dioxide combined with off‐line capillary gas chromatography/mass spectrometry. Class‐selective extraction has been performed with a single supercritical fluid by varying the extraction conditions. This method is applicable to the scale‐up, isolation and identification of toxic phenolic components in commercial extracts of G. biloba.
Simultaneous analysis of monoterpenes and diterpenoids of conifer oleoresin
Authors: Lewinsohn Efraim , Savage Thomas J. , Gijzen Mark , Croteau Rodney
Published: March 2007

A simple and rapid procedure for the simultaneous determination of monoterpenes and diterpenoid resin acids of conifer stem oleoresin is described; it involves tissue extraction with methyl tert‐butyl ether and methylation of the resin acids with CH2N2. The resin acid methyl esters and the monoterpenes are then analysed in a single gas chromatographic step. Enantiomer composition of the major monoterpene constituents is determined, after preliminary purification by thin layer chromatography, by capillary gas chromatography on a cyclodextrin column. The method is applicable to conifer species of high resin content (Iodgepole pine) and low resin content (grand fir).
Estimation of phyllanthin and hypophyllanthin by high performance liquid chromatography in Phyllanthus amarus
Authors: Sharma Anupam , Singh Ravneet T. , Handa Sukhdev S.
Published: March 2007

A reversed phase high performance liquid chromatographic procedure for standardizing a popular hepatoprotective Indian herb “Bhumyamlaki” (Phyllanthus amarus) on the basis of two of its bioactive lignans, phyllanthin and hypophyllanthin, has been developed. The method has been found to be sensitive, precise and to record more than 98% recovery of the two lignans. The leaves of P. amarus were found to contain the highest amounts of phyllanthin (0.7% w/w) and hypophyllanthin (0.3% w/w) as compared to the other parts of the plant.
Off‐line supercritical fluid extraction—high resolution gas chromatography applied to the study of moraceae species
Authors: Vilegas Janete H. Y. , Lanças Fernando M. , Vilegas Wagner , Pozetti Gilberto L.
Published: March 2007

Supercritical fluid extraction with CO2, performed in a home‐made system, of rhizomes of Dorstenia bryoniifolia Mart, ex Miq. (Moraceae) and of bark roots of Brosimum gaudichaudii Trécul (Moraceae) afforded crude extracts that were analysed by high resolution gas chromatography (HRGC). The D. bryoniifolia extract contained, besides the previously reported pimpinelin and isobergapten, the furocoumarins psoralen, bergapten, isopimpinelin and the triterpenes α‐ and β‐amyrin and the acetate of the latter. The B. gaudichaudii extract contained a number of terpenoids as well as the previously reported psoralen and bergapten. Supercritical fluid extraction gave extracts qualitatively similar to those obtained by Soxhlet extraction with hexane and, together with off‐line HRGC, was shown to be a fast and accurate technique to be used in rapid phytochemical examination.
A high performance liquid chromatographic method for the separation of hexose monophosphates and UDP glucose from plant extracts and its use to determine specific activities in radiotracer experiments
Authors: Viola R. , Davies H. V. , Sommerville L. B.
Published: March 2007

Anion exchange high performance liquid chromatography (HPLC) was used to separate UDP glucose (UDPGlc) and hexose monophosphates (HMPs) in crude ethanol extracts of potato tubers. Detection and quantification of UDPGlc and [U‐14C]UDPGlc was achieved with UV (A254) and radioactivity monitors connected in series. The 14C content in glucose 6‐phosphate (Glc‐6‐P), fructose 6‐phosphate (Fru‐6‐P) and glucose 1‐phosphate (Glc‐1‐P) was obtained following their enzymatic conversion to gluconate 6‐P and subsequent separation by HPLC. Individual HMPs were quantified by enzyme‐coupled reaction systems using a microplate reader equipped with a 340 nm filter. This approach allowed the specific activities of UDPGlc, Glc‐6‐P, Fru‐6‐P and Glc‐1‐P to be quantified in radiolabelled potato extracts within 2 h.
Determination of the sesquiterpene dialdehyde polygodial by high‐pressure liquid chromatography
Authors: van Beek Teris A. , van Dam Nicole , De Groot Aede , Geelen Threes A. M. , van der Plas Linus H. W.
Published: March 2007

A high‐pressure liquid chromatographic procedure for the determination of the antifeedant polygodial in Polygonum hydropiper leaves was developed. For leaves, the method consists of a selective extraction with hexane: EtOAc (8:2), pre‐purification of the evaporated extract over a solid phase C2 column, separation with a C18 RP‐HPLC column and detection/quantitation by means of UV at 233 nm. As internal standard α‐ionone is used. Advantages of the method are its selectivity and speed. Various aspects such as extraction efficiency, recovery, peak purity and reproducibility have been evaluated. The minimal detectable quantity is 1 ng.
Gas chromatography ‐ isotope ratio mass spectrometry measurements of some carboxylic esters from different apple varieties
Authors: Karl Volker , Dietrich Armin , Mosandl Armin
Published: March 2007

The δ13CPDB‐values of some carboxylic esters from apple flavours have been determined by capillary gas chromatography, on‐line coupled with isotope ratio mass‐spectrometry (GC‐IRMS) and compared with the isotopic ratios of some commercially available samples. For the first time, the chirospecific measurement of the isotopic ratios of 2‐methylbutanoates is described. Enantioselective capillary gas chromatography (enantio‐GC), GC‐IRMS as well as enantio‐GC‐IRMS are demonstrated as sophisticated methods in monitoring the authenticity of natural flavour compounds.
High performance liquid chromatographic analysis of aliphatic lichen acids
Authors: Huneck Siegfried , Feige Guido Benno , Lumbsch H. Thorsten
Published: March 2007

Aliphatic lichen acids can be transformed into their phenacyl esters which show strong absorption in the UV (ca. λ = 240 nm) and which can be used to detect these compounds following high performance liquid chromatography. Other suitable derivatives are the p‐nitrophenyl and benzyl esters, as well as the benzoates of the alcohols prepared from the acids by reduction of the corresponding methyl esters with lithium aluminium hydride.
Chiral compounds of essential oils XIV: Simultaneous stereoanalysis of buchu leaf oil compounds
Authors: Köpke Thomas , Dietrich Armin , Mosandl Armin
Published: March 2007

Multidimensional enantioselective gas chromatography, employing heart‐cutting from a non‐chiral precolumn onto a selectivity adjusted, modified cyclodextrin coated chiral main column, permits the simultaneous stereo differentiation of the chiral major compounds of buchu leaf oil. Commercially available essential oil as well as laboratory prepared samples were directly analysed. The enantiomeric distribution of limonene, menthone, isomenthone and pulegone was investigated, and the characteristic flavour impact compounds, 3‐oxo‐p‐menthane‐8‐thiol and its thiol acetate, were stereoanalysed. Their chirality evaluation is discussed as an indicator of authenticity of ‘cassis’ type fruit aromas and fragrances.
Diterpenes from the brown alga Dilophus mediterraneus
Authors: Goez Christiane E. , Wright Anthony D. , König Gabriele M. , Sticher Otto
Published: March 2007

From the dichloromethane extract of the brown alga Dilophus mediterraneus nine diterpenes, belonging to different skeletal classes, were isolated and characterised spectroscopically (MS, NMR, UV and IR). The structure of a new natural diterpene (1R*, 2E, 4R*, 7E, 11R*, 12S*)‐12, 18‐dihydroxydolabella‐2,7‐diene) was resolved with the aid of the lanthanide shift reagent Europium(III)‐tris(1,1,1,2,2,3,3)‐heptafluoro‐7,7‐dimethyl‐d6‐octa‐4,6‐dion‐d3, C30H3D27EuF21O6, (Eu(fod)3).
Separation and quantitation of stevioside and rebaudioside a in plant extracts by normal‐phase high performance liquid chromatography and thin‐layer chromatography: A comparison
Authors: Nikolova‐Damyanova Boryana , Bankova Vasya , Popov Simeon
Published: March 2007

Two similar methods, normal phase high performance liquid chromatography and silica gel thin‐layer chromatography with densitometry, were applied for the separation and quantitative determination of the diterpene glycosides stevioside and rebaudioside A in the leaves of the plant Stevia rebaudiana Bertoni. Results were compared and found to be very close in all basic features: resolution, accuracy and reproducibility. Thin‐layer chromatrography was found to be more suitable in case of phytochemical screening of large number of samples.
Desorption chemical ionization mass spectrometry of C‐glycosylflavones
Authors: Bakhtiar A. , Gleye J. , Moulis C. , Fourasté I.
Published: March 2007

Seventeen natural C‐glycosylflavones have been analysed using positive desorption chemical ionization mass spectrometry with ammonia as reagent gas. This technique provides the molecular weight, information for the identification of the aglycone, the sugar sequence, and the characterization of the C‐sugar (hexose, pentose). The distinction between mono‐C‐glycosylflavones, di‐C‐glycosylflavones, C‐glycosylflavone 2″‐O‐glycosides, and di‐C‐glycosylflavone 2‴‐O‐glycosides is also obtained.
A comparison of gas chromatography and high performance liquid chromatography for artemisinin analyses
Authors: Ferreira Jorge F. S. , Charles Denys J. , Wood Karl , Janick Jules , Simon James E.
Published: March 2007

An improved method for high performance liquid chromatography with electrochemical detection (HPLC‐EC) is presented for artemisinin analysis. It involves increased concentration of organic phase, elimination of the degassing step in sample preparation, and reduced time for heating and degassing in mobile phase preparation and recycling. The HPLC‐EC method was compared to a gas chromatographic (GC) method, which measured artemisinin indirectly through two of its degradation products, labelled A and B. Both methods provided a good separation of artemisinin from artemisitene, arteannuin B, and the semisynthetic dihydroartemisinin. Peak B provided a higher correlation to the levels of artemisinin detected by HPLC‐EC. Peaks A, B and Z (a small peak preceding A and B) were identified through electron impact and chemical ionization spectra from GC‐mass spectral analysis.