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Major Bioactive Constituents (major + bioactive_constituent)
Selected AbstractsIsolation and identification of metabolites from dihydromyricetinMAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2007Yansong Zhang Abstract Dihydromyricetin (DHM) is the major bioactive constituent of Rattan Tea, which is the tender stems and leaves of Ampelopsis grossendentata. Seven metabolites (2,8) of DHM (1) were obtained by the chromatographic method. The metabolites 2,5 were obtained from the urine of rats administered orally with DHM; and metabolites 6,8 were detected in the fecal specimens of rats, which were also produced by human intestinal bacteria (HIB) in vitro, and were separated from the cultured media of HIB containing DHM. Their structures were elucidated as 5,7,3,,5,-tetrahydroxyflavanonol (2); 5,7,3,,5,-tetrahydroxy-4,-methoxyflavanonol (3); 5,7,4,,5,-tetrahydroxy-3,-methoxyflavanonol (4); and dihydromyricetin- O -5-,- D -glucuronide (5); (2R,3S)-5,7,3,,4,,5,-pentahydroxyflavanonol (6); 3,4,5,7,3,,4,,5,-hepthydroxyflavan (7) and 5,7,3,,4,,5,-pentahydroxyflavanone (8) on the basis of UV, NMR and LC-MS/MS data. These seven metabolites were formed through familiar metabolic reactions. Dihydromyricetin- O -5-,- D -glucuronide (5) is a new compound. The 13C-NMR data of (2) and (4) are reported for the first time. Copyright © 2007 John Wiley & Sons, Ltd. [source] Characterization of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen) by high-performance liquid chromatography with electrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2006Min Yang The qualitative analysis of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen in Chinese) was performed using high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (ESI-MSn). Tanshinones are the major bioactive constituents of Dan-shen, which is used in China for the treatment of haematological abnormalities and cardiovascular diseases. The ESI-MSn fragmentation behavior of tanshinones was investigated. For tanshinones with the tanshinone I nucleus, the fragmentation was triggered by loss of a molecule of CO except bearing a substituent at C17 or C18, followed by sequential eliminations of CO. If C15,16 was a saturated bond, the fragmentation was triggered by elimination of a molecule of H2O. For tanshinones with the tanshinone IIA nucleus, the fragmentation was triggered by loss of a molecule of H2O, followed by successive eliminations of CO. Ions corresponding to loss of a molecule of propylene (,m,=,42) were also observed. Moreover, when C15,16 was a saturated bond, ions corresponding to losses of CH3, H2O and propylene were more abundant. If no D-ring existed, the presence of isopropyl resulted in an elimination of a molecule of H2O with an adjacent CO or OH. In addition, the extension of the , -conjugation in the A-ring (especially at C1,2) induced the fragmentation by loss of a molecule of CO. These fragmentation rules were applied to the identification of tanshinones in a chloroform/methanol (3:7) extract of Dan-shen, which was separated on a C18 column with gradient elution. A total of 27 tanshinones were identified, including five new constituents. The established method could be used for the sensitive and rapid identification of tanshinones in the Dan-shen drug and its pharmaceutical preparations. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis of bufadienolides in the Chinese drug ChanSu by high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2005Min Ye The qualitative analysis of bufadienolides in the Chinese drug ChanSu was performed using high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS). Bufadienolides are the major bioactive constituents of ChanSu, which is used to treat heart failure and cancer in traditional Chinese medicine. The APCI-MS fragmentation behavior of bufadienolides was studied. For bufadienolides with only hydroxyl substituents, the fragmentation was characterized by successive eliminations of H2O and CO molecules, and the profile of MS/MS product ions was correlated with the number of hydroxyl groups. If a C-16 acetoxyl group was present, the fragmentation of [M+H]+ ions was triggered by initial loss of 60,Da (HOAc). The elimination of CO was significant for bufadienolides with a 19-formyl group, and the 19-hydroxyl group could be characterized by the loss of 30,Da (HCHO). These fragmentation rules were applied to the identification of bufadienolides in a methanolic extract of ChanSu, which was separated on a C18 column with gradient elution. A total of 35 bufadienolides were identified, including four new constituents. The method established here facilitated the convenient and rapid quality control of ChanSu crude drug and its pharmaceutical preparations. Copyright © 2005 John Wiley & Sons, Ltd. [source] Characterization of phenolic compounds in the Chinese herbal drug Tu-Si-Zi by liquid chromatography coupled to electrospray ionization mass spectrometry,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2005Min Ye Phenolic compounds are the major bioactive constituents of the Chinese herbal drug Tu-Si-Zi, which is prepared from the seeds of Cuscuta chinensis. However, seeds of C. australis also are offered under the name of this drug in the herb market. In order to make a comparison of their chemical constituents, the phenolic compounds of these two Cuscuta species were analyzed by high-performance liquid chromatography/diode-array detection/electrospray ion trap tandem mass spectrometry (HPLC/DAD/ESI-MSn). A total of 50 compounds were observed in the methanol extracts, including 23 flavonoids, 20 lignans and 7 quinic acid derivatives. These compounds were separated on a C18 column and identified or tentatively characterized based on UV spectra and MS fragmentation behavior. In contrast to previous reports, the phenolic patterns of these two Cuscuta species were found to be very different. Kaempferol and astragalin were the predominant constituents of C. australis, while hyperoside was the major compound in C. chinensis. Most of the identified compounds, especially the acylated flavonoid glycosides, have not previously been reported from Cuscuta species. In addition, a 30,Da neutral loss observed for flavonols was investigated and could be used to differentiate flavonoid isomers such as kaempferol and luteolin. The ESI-MS fragmentation behavior of furofuran lignans was also investigated, and a characteristic pathway is proposed. The large differences observed between the phenolic constituents of C. chinensis and C. australis strongly encouraged further comparison of the bioactivities of these two species. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||