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New Constituents (new + constituent)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

New Constituents from the Leaves of Morinda citrifolia.

CHEMINFORM, Issue 28 2007
Junko Takashima
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Two New Constituents from the Bark of Holarrhena pubescens.

CHEMINFORM, Issue 32 2003
Bina Shaheen Siddiqui
No abstract is available for this article. [source]

Ecdysteroids from Silene viridiflora

HELVETICA CHIMICA ACTA, Issue 4 2009
András Simon
Abstract Two new ecdysteroid acetonide derivatives, 5, -2-deoxy-20-hydroxyecdysone 20,22-acetonide (6) and makisterone C 2,3;20,22-diacetonide (8), were isolated from the dried herb of Silene viridiflora. The already known 5, -2-deoxy-20-hydroxyecdysone 20,22-acetonide (7) is additionally reported here as a new constituent of S. viridiflora. Five earlier described S. viridiflora ecdysteroids, integristerone A (1), 5,20,26-trihydroxyecdysone (26-hydroxypolipodine B; 2), 20,26-dihydroxyecdysone (3), 2-deoxy-20-hydroxyecdysone (4), 2-deoxyintegristerone A (5), are also included because of their improved characterization. The structures were established via spectroscopic analyses, including one- and two-dimensional NMR and mass spectrometry. [source]

Characterization of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen) by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2006
Min 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 spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2005
Min 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]