Qualitative and quantitative analysis of diterpenoids in Salvia species by liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.
ABSTRACT An on-line ultra-high-performance liquid chromatography (UHPLC) coupled with photodiode-array detection and quadrupole time-of-flight tandem mass spectrometry (QTOF-MS/MS) method has been optimized and established for the qualitative and quantitative analysis of the important diterpenoids in the methanol extracts of 12 Salvia species. Specific marker components were identified for the classification of the Salvia samples by principal component analysis. The accurate mass measurement within 3 ppm error for all the protonated molecules and subsequent fragment ions offers higher quality structural information for interpretation of fragmentation pathways of various groups of diterpenoids. Thus, a total of 21 diterpenoids from different Salvia species were separated within 10 min, and were unequivocally or tentatively identified via comparisons with authentic standards and literature. This UHPLC-QTOF-MS/MS method was validated to be sensitive, precise and accurate with the limit of detections at 3.0-16 ng/ml, and the overall intra-day and the inter-day variations less than 3%. The recovery of the method was in the range of 96.2-101.8%, with relative standard deviation (RSD) less than 3.0%. The results demonstrated that the qualitative and quantitative differences in diterpenoids were not only useful for chemotaxonomy in some Salvia species but also for the standardization and differentiation of large numbers of similar samples.
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ABSTRACT: Tanshinones are a class of abietane diterpene compound isolated from Salvia miltiorrhiza (Danshen or Tanshen in Chinese), a well-known herb in Traditional Chinese Medicine (TCM). Since they were first identified in the 1930s, more than 40 lipophilic tanshinones and structurally related compounds have been isolated from Danshen. In recent decades, numerous studies have been conducted to investigate the isolation, identification, synthesis and pharmacology of tanshinones. In addition to the well-studied cardiovascular activities, tanshinones have been investigated more recently for their anti-cancer activities in vitro and in vivo. In this review, we update the herbal and alternative sources of tanshinones, and the pharmacokinetics of selected tanshinones. We discuss anti-cancer properties and identify critical issues for future research. Whereas previous studies have suggested anti-cancer potential of tanshinones affecting multiple cellular processes and molecular targets in cell culture models, data from in vivo potency assessment experiments in preclinical models vary greatly due to lack of uniformity of solvent vehicles and routes of administration. Chemical modifications and novel formulations had been made to address the poor oral bioavailability of tanshinones. So far, human clinical trials have been far from ideal in their design and execution for the purpose of supporting an anti-cancer indication of tanshinones.International Journal of Molecular Sciences 01/2012; 13(10):13621-66. · 2.46 Impact Factor
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ABSTRACT: BACKGROUND: Electrospray tandem mass spectrometry approach is widely used for the rapid characterization of natural products. This paper describes the gas-phased ESI-MS/MS fragmentation of abietane-type diterpenoids and their novel dimeric conjugate, salvialeriafone (1) using both positive and negative ion electrospray ionization quadropole time-of-flight mass spectrometry (ESI-QqTOF-MS/MS) hybrid instrument. Diterpenoids are widely distributed throughout the plant kingdom and posses interesting biological activities. RESULTS: ESI-QqTOF-MS (positive ion mode) of diterpenoids 1--6 under collision-induced dissociation tandem mass spectrometric analysis (CID-MS/MS) showed the characteristic losses of water, carbonmonoxide and propene molecules, while analysis in negative ion mode showed the characteristic losses of water, carbon monoxide, methane molecules and methyl radical. Results demonstrated the differences in the product ions and base peaks due to the differences in the skeleton. A novel dimeric conjugate, salvialeriafone (1) showed characteristic fragmentation pattern and was found to be more prone to form radical ions, as compared to monomeric diterpenoids. The fragmentation pathways of characteristic fragments were proposed with the aid of HRESIMS. CONCLUSIONS: Extensive tandem mass spectrometric studies of salvialeriafone (1) and related diterpenoids 2--6 were conducted and their characteristic fragments were identified. The knowledge of the fragmentation pattern of these diterpenoids will be useful for the characterization of new dimers of this class of compounds.Chemistry Central Journal 10/2012; 6(1):120. · 1.31 Impact Factor
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ABSTRACT: A reliable and sensitive ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method has been optimized and established for analysis of protostane triterpenoids in a commonly used traditional Chinese herbal medicine Alisma orientalis (Sam.) Juzep. The separation of crude extract of A. orientalis was achieved on a Waters ACQUITY HSS T3 column (100 mm x 2.1 mm, 1.8 microm) eluting with 0.1% (v/v) formic acid/acetonitrile. A total of 20 protostane triterpenoids including 19 known compounds and a new one were well separated within 7 min. The collision-induced dissociation (CID) tandem mass spectrometric (MS/MS) fragmentation patterns of protostane triterpenoids was firstly reported in this study. The hydrogen rearrangement at the C-23-OH leads to dissociation of the bond between C-23 and C-24 in the protostane triterpenoid skeleton during the CID process. This dissociation was the characteristic CID fragmentation pathway of this class of triterpenoids, and was useful for further differentiation of some positional isomers which contain an acetyl unit on the C-23 or C-24 position. The identities of isolated compounds were identified by comparing their retention times and CID fragmentation behaviors with those of reference standards or tentatively assigned by matching the empirical molecular formulae with those reported in the literature. It is concluded that this newly established UPLC/Q-TOF-MS method is a powerful approach for structural elucidation of protostane triterpenoids isolated from A. orientalis.Rapid Communications in Mass Spectrometry 06/2010; 24(11):1514-22. · 2.51 Impact Factor