Characteristic fragmentation patterns of trimethylsilyl and trimethylsilyl-oxime derivatives of plant disaccharides as obtained by gas chromatography coupled to ion-trap mass spectrometry.

The characteristic fragmentation pattern of six reducing and two non reducing type disaccharides-(neohesperidose, acuminose, sambubiose, rutinose, vicianose, primverose, and two arabinosyl-inositols) has been described. These saccharides have not been previously identified by on-line chromatographic techniques. Unambiguous specific characteristics of the TMS (oxime)s such as mass distribution, syn/anti oximes ratios and elution order proved to be associated with their reducing or non reducing character, with their aldosyl property and with the position of their O-glycosidic linkages. The practical utility of the mass fragmentation study of these rare disaccharides was demonstrated, at the first time, by the simultaneous, on-line identification and quantification of the acuminose, vicianose, primverose and arabinosyl-inositol contents of tea leaves, from green and black tea blends of Indian and Chinese origin.

Complementary fragmentation pattern analysis by gas chromatography-mass spectrometry and liquid chromatography tandem mass spectrometry confirmed the precious lignan content of Cirsium weeds.

In this paper, as novelties to the field, it is confirmed at first, that the fruits of Cirsium species, regarded as injurious weeds, do contain lignans, two, different butyrolactone-type glycoside/aglycone pairs: the well known arctiin/arctigenin and the particularly rare tracheloside/trachelogenin species. These experiences were supported by gas chromatography-mass spectrometry (GC-MS), by liquid chromatography tandem mass spectrometry (LC-MS/(MS)) and by nuclear magnetic resonance (NMR) spectroscopy. The study reflects the powerful impact of the complementary chromatographic mass fragmentation evidences resulting in the identification and quantification, the extremely rare, with on line technique not yet identified and described, tracheloside/trachelogenin pair lignans, without authentic standard compounds. Fragmentation pattern analysis of the trimethylsilyl (TMS) derivative of trachelogenin, based on GC-MS, via two different fragmentation pathways confirmed the detailed structure of the trachelogenin molecule. The complementary chromatographic evidences have been unambiguously confirmed, by (1)H and (13)C NMR analysis of trachelogenin, isolated by preparative chromatography. Identification and quantification of the fruit extracts of four Cirsium (C.) species (C. arvense, C. canum, C. oleraceum, and C. palustre), revealed that (i) all four species do accumulate the tracheloside/trachelogenin or the arctiin/arctigenin butyrolactone-type glycoside/aglycone pairs, (ii) the overwhelming part of lignans are present as glycosides (tracheloside 9.1-14.5 mg/g, arctiin 28.6-39.3 mg/g, expressed on dry fruit basis), (iii) their acidic and enzymatic hydrolyses to the corresponding aglycones, to trachelogenin and arctigenin are fast and quantitative and (iv) the many-sided beneficial trachelogenin and arctigenin can be prepared separately, without impurities, excellent for medicinal purposes.

Mass fragmentation study of the trimethylsilyl derivatives of arctiin, matairesinoside, arctigenin, phylligenin, matairesinol, pinoresinol and methylarctigenin: their gas and liquid chromatographic analysis in plant extracts.

The mass fragmentation patterns and the characteristic behavior of the trimethylsilyl (TMS) derivatives of the dibenzylbutyrolactone-type (arctiin, arctigenin, methylarctigenin, matairesinoside, matairesinol) and those of the diphenylperhydrofurotetrahydrofurane-type (phylligenin, pinoresinol) lignans, obtained by gas chromatography-mass spectrometry (GC-MS), were presented. It was shown that upon acidic hydrolysis the dibenzylbutyrolactone-type lignans are stable while the diphenylperhydrofurotetrahydrofurane-type ones decompose. As a novelty to the field we confirmed that the fragment species of the derivatized lignan glycosides, in the presence of excess hexamethyldisilazane, leaded to their in situ derivatization. Quantification of the selective fragment ions of the TMS derivatives by GC-MS, in respect of the ions found one by one, and concerning the selective fragment ions {SFI(s)} in total, provided acceptable reproducibilities, suitable for quantitation purposes: varying between 1.20% and 6.6% relative standard deviation percentages (RSD%). For characterization of the behavior of various type of lignans, analyses were performed with the untreated and with the trifluoroacetic acid hydrolyzed plant extracts, from the same sample, in parallel, both by GC-MS and by high performance liquid chromatography-mass spectrometry, working in the positive electron ionization mode (HPLC-ESPI-MS). The analysis of lignans in fruit and leaf extracts (obtained from the Arctium, Centaurea and Forsythia plants) was confirmed both by GC-MS and by HPLC-ESPI-MS. Our multicomponent system (including the identification and quantification of sugars, sugar alcohols, and several members of various homologous series of acids, anthraquinones and flavonoids) has been extended to the analysis of lignan glycosides and to the free lignans. Reproducibilities in the quantitation of lignans in plant matrices, as averages on GC and HPLC basis, varied between 0.9% and 11% (RSD). The distribution of the lignan constituents was presented for 5 Arctium, for 8 Centaurea and for 4 Forsythia plant extracts: the total of lignan contents varied between 0.42 and 87.9 mg/g, respectively.