摘要:

AbstractA method of sample preparation using strong cation exchange solid phase extraction is described which enables the separation of phenolics and quinolizidine alkaloids in methanolic extracts ofGenistaspecies. The method has been used for determination of both groups of compounds with only one extraction step. The phenolics, flavonoids and isoflavonoids were analysed quantitatively by high performance liquid chromatography, avoiding UV absorbing alkaloids disturbing the detection of phenolics. At the same time the fingerprint patterns of the alkaloids could be obtained by gas liquid chromatography. Considering alkaloid, flavonoid and isoflavonoid patterns together, more detailed chemotaxonomic studies are possible and only small quantities of plant material are required.

ISSN:0958-0344    

DOI:10.1002/pca.2800060302

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAn improved bioautographic agar overlay method was developed for the detection of antimicrobial compounds from crude plant extracts using phenol red and a tetrazolium compound as dyes to improve resolution. This method worked successfully with a wide variety of microorganisms including a number of Gram‐positive and Gram‐negative bacteria and fungi. Phenol red and the test organisms were incorporated directly into nutrient agar that was overlayed onto a thin layer chromatogram of plant extracts. In the case of bacteria, after spraying with thiazolyl blue (methylthiazolyltetrazolium chloride), dark red coloured inhibition zones appeared against blue background. Satisfactory results were obtained even with those compounds which were present in very small quantities. This method proved to be useful for activity‐guided fractionation or for target‐directed isolation of the active constituents of

ISSN:0958-0344    

DOI:10.1002/pca.2800060303

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractRacemic mixtures of syntheticcis‐ ortrans‐4‐methyl‐5‐decanolide were separated by enantioselective high performance liquid chromatography with Chiraspher‐RT to yield all four stereoisomers as enantiopure compounds of distinct odour activities. In order to elucidate stereochemical features the isolated stereoisomers were reduced to their corresponding 4‐methyl‐1,5‐decandiols by reductive ester cleavage with lithium aluminium hydride. Absolute configurations were derived from proton nuclear magnetic resonance studies of diastereomeric di‐(R)‐2′‐methoxy‐2′‐trifluoromethylphenylacetic acid esters of these 1,5‐diols. Using enantioselective multidimensional capillary gas chromatography (column combination SE 52/heptakis‐(2,3‐di‐O‐methyl‐6‐O‐tert butyldimethylsilyl)‐β‐cyclodextrin), the direct enantioselective analysis of all four lactone stereoisomers was achieved. The application of this method to the scent of living, white flowering orchids (Aerangis confusa) provescis‐(4S)‐methyl‐(5S)‐decanolid

ISSN:0958-0344    

DOI:10.1002/pca.2800060304

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper reports the identification of sanguinarine and coptisine isolated from the crude extract of callus culture ofChelidonium majusby positive fast ion bombardment (FIB+) mass spectrometry (MS) and FIB+tandem mass spectrometry (MS‐MS). Callus was cultivated on Gamborg B5 medium for three weeks at 25°C and extracted with 70% ethanol. The alkaloids were extracted into chloroform, following ion pair formation, and then separated on a silica gel column. The presence of sanguinarine and coptisine was initially determined from chromatographic analysis, and the structures of the compounds were confirmed by MS. MS‐MS analysis was not suitable for coptisine since this compound did not produce daughter

ISSN:0958-0344    

DOI:10.1002/pca.2800060305

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractEvaporative light scattering and thermospray mass spectrometry have been investigated as two alternative methods for the liquid chromatographic detection of ginkgolides and bilobalide. Both techniques were used to quantify these metabolites in leaf extracts and in some phytopharmaceuticals. Only a minimum of sample pre‐purification was required. Results were compared with those obtained by gas chromatography (flame ionization detection), which is one of the most suitable methods for routine determinations of such compounds. The isolation of ginkgolides A, B, C, and J and bilobalide from leaves ofGinkgo bilobais also describe

ISSN:0958-0344    

DOI:10.1002/pca.2800060306

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe taxane content of the needles of 57 cultivars obtained from five major nurseries in the United States is presented. The analysis of taxol (1), and five other related taxanes, 10‐desacetyl‐7‐epi‐taxol (2), cephalomannine (3), 10‐desacetyl taxol (4), baccatin III (5) and 10‐desacetyl baccatin III (6) was carried out using a high performance liquid chromatographic method developed in our laboratory. The results of these analyses showed that the total “useful” taxanes varied between 0.0232%‐0.113%, with 1 and 6 being the most abundant taxanes. The survey identified 11 cultivars with a content of 1 ranging from 0.028% to 0.062%, and ten cultivars with a content of 6 ranging from 0.028% to 0.066%; 3 and 4 each represented approximately 30%‐50% of the concentration of taxol in most cultivars. Therefore, the needles of ornamentalTaxusrepresent a significant, rich and renewable source for taxol and ot

ISSN:0958-0344    

DOI:10.1002/pca.2800060307

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSaponins have been extracted from the seed ofDodonaea attenuataand converted to prosapogenins by mild acid hydrolysis. Partially acetylated derivatives of the sapogenin, R1‐barrigenol, were characterized by extensive two dimensional nuclear magnetic resonance spectroscopy. The complete assignments of1H and13C resonances and nuclear Overhauser effects of these partly acetylated sapogenins has allowed a straightforward assignment of the structures of the prosapogenins, including the location of the individual ester groups and the presence of artefacts from the acidic hydrolysis condition

ISSN:0958-0344    

DOI:10.1002/pca.2800060308

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800060310

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800060312

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800060313

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY