摘要:

AbstractThe alkaloids present in the leaves ofErythrina berteroanaandE. poeppigianahave been screened by gas chromatography and mass spectrometry. Samples of milk from goats which had been fed with leaves of these plants have also been analysed. Traces of β‐erythroidine were detected in the milk and this raised the question of whether it was suitable for human consumpti

ISSN:0958-0344    

DOI:10.1002/pca.2800040302

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractCultured roots ofStephania cepharantha, rich in the bisbenzylisoquinolines aromoline (1) and berbamine (2), were fed [3‐13C]tyrosine. The labelled alkaloids were isolated.13C NMR spectra showed that13C was specifically incorporated into sites on 1 and 2. The ratios of13C 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 intermediat

ISSN:0958-0344    

DOI:10.1002/pca.2800040303

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA high performance liquid chromatographic (HPLC) method was developed for the qualitative and quantitative determination of L‐tyrosine and six common tetrahydroisoquinoline alkaloids (papaverine, noscapine, sanguinarine, morphine, codeine and thebaine) ofPapaver somniferum.The reversed phase HPLC method yields baseline separation of the alkaloids in 20 min and is achieved using a simple H2O: MeOH linear gradient. Silanol effects commonly associated with the separation of such strongly basic compounds were minimized by the addition of the amine modifier, triethylamine, to the mobile phas

ISSN:0958-0344    

DOI:10.1002/pca.2800040304

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA method has been developed to determine the content of the bioactive diterpenoid triptolide in specimens ofTripterygium hypoglaucumandT. wilfordiiobtained from 21 different districts of China. Triptolide was extracted from powdered plant material with chloroform and, following removal of alkaloids, esterified with CH2N2and silylated withN‐(trimethylsilyl)imidazole. Samples were analysed quantitatively by high resolution gas chromatography withn‐hexatriacontane as internal standard. The minimum level of detection of triptolide was 25 ng and mean recoveries of 96% (relative standard deviation 8.7%) were recorded for extracts containing 25–75 μg/mL of the diter

ISSN:0958-0344    

DOI:10.1002/pca.2800040305

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA normal phase thin layer chromatographic procedure for the separation and detection of bilobalide and ginkgolides A, B, C and J has been developed. The method is based on the impregnation of commercially available silica gel F254 plates with sodium acetate. Silica gel thus impregnated gives a good separation of all major terpene trilactones in ginkgo leaves (0.06 ⩽ ΔRf0.17) with the solvent systems ethyl acetate: hexane (9:1) (non‐saturated chamber) or 100% methyl acetate (saturated chamber). The sodium acetate has two functions: it greatly improves the separation of the ginkgolide pairs G‐A/G‐B and G‐J/G‐C, and it enhances the sensitivity of the acetic anhydride spray reagent. Quantities of less than 1 μg of all four ginkgolides and bilobalide ca

ISSN:0958-0344    

DOI:10.1002/pca.2800040306

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractIn this paper the determination of taxol and the related compounds 10‐deacetyltaxol, cephalomannine and 10‐deacetylcephalomannine in various parts ofTaxus cuspidataSieb 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 i

ISSN:0958-0344    

DOI:10.1002/pca.2800040307

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractKernels from Michigan‐grown tart cherryPrunus cerasusL. cv. Montmorency were frozen at −40°C, lyophilized, crushed and extracted sequentially with hexane and methanol. Amygdalin, mandelonitrile and benzaldehyde were present in the kernel extracts and were quantified by high performance liquid chromatography. Amygdalin was found to be the major component, while free mandelonitrile is detected for the first time in the tart cherry pit ker

ISSN:0958-0344    

DOI:10.1002/pca.2800040308

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA capillary gas chromatographic (GC) method for the assay of cinnamic acid and 4‐coumaric acid in alfalfa (Medicago sativaL.) 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 w

ISSN:0958-0344    

DOI:10.1002/pca.2800040309

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractDifferent substrates were used in reaction assays for rosmarinic acid synthase, an enzyme involved in rosmarinic acid biosynthesis in cell cultures ofColeus blumei.In order to introduce the cinnamoyl moiety of the ester, 4‐coumaroyl‐CoA and caffeoyl‐CoA were applied as substrates; for the hydroxyphenyllactic acid moiety, 4‐hydroxyphenyllactate and 3,4‐dihydroxyphenyllactate were used. Four different reaction products were thus produced and these were analysed by ion spray mass spectrometry and tandem mass spectrometry after purification by semi‐preparative high pressure liquid chromatography. The molecular masses and the fragmentation patterns obtained by tandem mass spectrometry of the reaction products formed by the catalysis of rosmarinic acid synthase were in agreement with the structures of rosmarinic acid (caffeoyl‐3′,4′‐dihydroxyphenyllactate) and rosmarinic acid‐like esters (4‐coumaroyl‐4′‐hydroxyphenyllactate, 4‐coumaroyl‐3′,4′‐dihydroxyphenyllactate, caffeoyl‐4′‐hydroxyphenyllactate) as expected f

ISSN:0958-0344    

DOI:10.1002/pca.2800040310

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800040311

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY