PHYTOCHEMICAL ANALYSIS
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2022
·Vol. 33
·期 6
·895-905
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IF 3.024
Li Cheng,Fang Wang,Yuanxin Cao,Chaoying Tong,Qisheng Wei,Shuyun Shi,Ying Guo
Introduction Citri Reticulatae Pericarpium Viride (CRPV, Qing Pi in Chinese) has been widely used in traditional Chinese medicine. Polymethoxylated flavonoids (PMFs), which are a special group of flavonoids with strong antitumor activity, are broadly distributed in citrus peels. However, systematic investigation of antitumor PMFs in CRPV has received little attention to date. Objectives An MCF-7 cell biospecific extraction method integrated with neutral loss/diagnostic ion filtering-based HPLC-QTOF-MS/MS strategy was developed for rapid and specific profiling of antitumor PMFs and systematic identification of PMFs in CRPV. Methodology By incubating MCF-7 cells with CRPV extract, potential antitumor PMFs specifically bound to cells and were isolated. Then, by systematic investigation of fragmentation pathways, neutral loss and diagnostic ion filtering strategies were proposed to comprehensively and accurately identify PMFs. Results Sixteen antitumor PMFs were unambiguously or tentatively identified. Among them, minor compound 15 (5-hydroxy-6,7,8,3′,4′-pentamethoxyflavone with a free hydroxyl group at C-5) exhibited excellent antitumor activity, with an IC 50 value of 2.81 ± 0.76 μg/mL, which is lower than that of 5-fluorouracil (IC 50 , 4.92 ± 0.83 μg/mL). Nobiletin ( 12 ) and tangeretin ( 16 ), two major PMFs, presented moderate antitumor activities with IC 50 values of 13.06 ± 1.85 and 17.07 ± 1.18 μg/mL, respectively, and their contents were sensitively and precisely determined. Conclusions To the best of our knowledge, this is the first report on the systematic investigation of antitumor PMFs in CRPV. The study will lay a foundation for the quality control and clinical application of CRPV.
研究领域:
中药学
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分析化学
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肿瘤学
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PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2026
·
IF 7.3
Bairong Fu,Dongqin Tan,Jing Jin,Lei Tong,Longxing Wang,Yihou Peng,Ningbo Geng,Lidong Wu,Huilian Ma,Yuwen Ni,Jiping Chen
The fragmentation behavior of isomeric hydroxylated polybrominated diphenyl ethers (OH-PBDEs) remains poorly elucidated, although LC-MS/MS is essential for their analysis. This study systematically characterizes their fragmentation behavior by LC-ESI-MS2, elucidating relationships between product ions, structural features, and instrument detection limits. Results demonstrated congener-specific variability in the signal intensity of [M–H]−, particularly among isomers. Fragmentation behavior is highly dependent on the hydroxyl location on the diphenyl ether scaffold, as well as the bromine substituent pattern. Three distinct mechanisms are identified: (1) Br abstraction via free radical-mediated rearrangement cleavage in meta-hydroxylated PBDEs, (2) preferential formation of the [Br]− ion via γ-elimination in ortho-hydroxylated PBDEs, and (3) characteristic formation of bromobenzoquinone anions via multistep fragmentation mechanisms in para-hydroxylated PBDEs. Furthermore, the ortho-effect, particularly pronounced in 2′–OH substituted congeners, significantly alters the fragmentation pathways. While the elucidated fragmentation pathways provided structural insights, the inherent weak signals challenged detection. A sensitivity-enhancing precolumn derivatization protocol with dansulfonyl chloride was introduced to solve the problem. The MS2 fragmentation of these derivatives was conveniently dominated by the cleavage of the C–S bond within the dansyl group, yielding abundant diagnostic ions that greatly aided in structural confirmation. As predicted, the derivatization strategy achieved a remarkable up to 15-fold improvement in the sensitivity. This investigation advances the understanding of OH-PBDE fragmentation, establishes an identification framework using specific patterns and diagnostic ions, and demonstrates a practical derivatization approach for enhanced sensitivity, elucidating structure-fragmentation relationships in brominated aromatics and providing methodological guidance for future analysis.
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高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2012
·Vol. 137
·期 12
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IF 3.333
Guan Jiwen,Hu Yongjun,Zou Hao,Cao Lanlan,Liu Fuyi,Shan Xiaobin,Sheng Liusi
In present study, photoionization and dissociation of acetic acid dimers have been studied with the synchrotron vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. Besides the intense signal corresponding to protonated cluster ions (CH 3 COOH) n ·H + , the feature related to the fragment ions (CH 3 COOH)H + ·COO (105 amu) via β-carbon-carbon bond cleavage is observed. By scanning photoionization efficiency spectra, appearance energies of the fragments (CH 3 COOH)·H + and (CH 3 COOH)H + ·COO are obtained. With the aid of theoretical calculations, seven fragmentation channels of acetic acid dimer cations were discussed, where five cation isomers of acetic acid dimer are involved. While four of them are found to generate the protonated species, only one of them can dissociate into a C–C bond cleavage product (CH 3 COOH)H + ·COO. After surmounting the methyl hydrogen-transfer barrier 10.84 ± 0.05 eV, the opening of dissociative channel to produce ions (CH 3 COOH) + becomes the most competitive path. When photon energy increases to 12.4 eV, we also found dimer cations can be fragmented and generate new cations (CH 3 COOH)·CH 3 CO + . Kinetics, thermodynamics, and entropy factors for these competitive dissociation pathways are discussed. The present report provides a clear picture of the photoionization and dissociation processes of the acetic acid dimer in the range of the photon energy 9–15 eV.
研究领域:
化学物理学
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光谱学
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计算化学
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高影响因子
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