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Alberto Plaza Sonia Piacente Angela Perrone Arafa Hamed Cosimo Pizza Giuseppe Bifulco 《Tetrahedron》2004,60(52):12201-12209
Stemmosides C and D, two novel pregnane glycosides characterized by an unusual C-17 side chain were isolated from the pericarps of Solenostemma argel. In addition, stemmoside D displays an uncommon 14β proton configuration, apparently being the first pregnane isolated from plants known to have a 15 keto, cis CD ring junction. Their structures have been established by ESIMS and NMR experiments. The relative configuration of the molecules was determined using a strategy based on the simulation of 1H, 13C, and J coupling NMR parameters. DFT calculations of 1H and 13C chemical shifts, and of the 1H homonuclear spin–spin coupling constants were performed with the mPW1PW91 functional using the 6-31G(d,p) basis set on the fully optimized geometries of all the possible stereoisomers. 相似文献
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Bedir E Calis I Piacente S Pizza C Khan IA 《Chemical & pharmaceutical bulletin》2000,48(12):1994-1995
A new flavonol glycoside, isorhamnetin 3-O-beta-D-apiofuranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-galactopyranoside, and the known diglycoside, isorhamnetin 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside were isolated from the aerial parts of Astragalus vulneraria. Characterization of the two compounds was done by spectroscopic methods (1D and 2D NMR, and FAB-MS). 相似文献
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A novel steroidal glycoside has been isolated from the starfish Protoreaster nodosus. The structure includes a 3β,5α,6β,8β,15α,24ξ-hexahydroxysteroidal moiety and a sugar moiety [2-0-methyl-β-D-xylopyranosyl-(1 → 2)-α-L-arabinofuranosyl] which is glycosidically attached at C-24 of the aglycone. 相似文献
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Montoro P Tuberoso CI Perrone A Piacente S Cabras P Pizza C 《Journal of chromatography. A》2006,1112(1-2):232-240
Anthocyanins in extracts of berries of Myrtus communis, prepared following a typical Sardinia myrtle liqueur recipe, were identified and quantified by HPLC coupled with electrospray/tandem mass spectrometry using, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of the anthocyanidins were dependent on the MS technique employed, and differed considerably from those previously reported. The anthocyanin profile of five anthocyanin glucosides and four anthocyanin arabinosides, the latter not previously identified in this specie, was specific for myrtle berry extracts. The quantitative compositions of extracts of myrtle berries derived from different geographical areas in Italy were compared. 相似文献
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Qualitative and quantitative analyses of phenolic compounds are of interest for both medicinal and food plants. In the present work, the phenolic fraction from Yucca schidigera, a plant bearing the GRAS (Generally Recognized as Safe) label approved by the US Food and Drug Administration, was studied. Crude extracts of Y. schidigera bark were investigated by liquid chromatography/UV spectrophotometry with diode-array detection, liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS), in order to develop and optimize simple and rapid techniques to determine both stilbenes and yuccaols for the purposes of quality control of collected material. With optimal LC and MS conditions, stilbenes and yuccaols were quantified with all the proposed methods and the results were compared. Sensitivity was evaluated and the results indicated that MS/MS detection in the multiple reaction monitoring mode is easily applicable to this plant and allows the rapid and direct identification and quantification of these peculiar compounds in crude plant extracts. 相似文献
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Rodrigues CM Rinaldo D dos Santos LC Montoro P Piacente S Pizza C Hiruma-Lima CA Brito AR Vilegas W 《Rapid communications in mass spectrometry : RCM》2007,21(12):1907-1914
Direct flow injection electrospray ionization ion trap tandem mass spectrometry (ESI-IT-MS/MS) was used to investigate the polyphenolic compounds present in an infusion from the barks of Hancornia speciosa Gom. (Apocynaceae), a native Brazilian plant popularly known as 'mangabeira', used as a source of nutrition and against gastric disorders. After a simple sample filtration pretreatment the characteristic fingerprint of the infusion was performed in negative ion ESI mode in a few minutes. At low capillary-voltage activation, the deprotonated molecules ([M--H]-) were observed and using collision-induced dissociation the product ion spectra showed the presence of a homologous series of B-type proanthocyanidins, as well as another series containing their respective C-glycosylated derivatives, with a degree of polymerization from 1 up to 6 units of interlinked catechins. Therefore, direct flow injection allowed us to identify the key compounds without preparative isolation of the components. 相似文献
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M. D. Alaniya N. Sh. Kavtaradze C. Bassarello A. V. Skhirtladze C. Pizza I. Kutateladze 《Chemistry of Natural Compounds》2006,42(6):681-685
New flavonoid oligosides, the structures of which were established by chemical transformations and UV, IR, PMR, and 13C NMR spectra, were isolated from Astragalus galegiformis leaves.
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Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 555–558, November–December, 2006. 相似文献