中药库拉索芦荟化学成分的液质定性分析

Qualitative analysis of chemical constituents of Aloe made from Aloe barbadensis by liquid chromatography-mass spectrometry

关键词:  芦荟, HPLC-DAD-ESI-IT-TOF-MSⁿ, 蒽醌, 蒽酮, 色酮, 化学成分, 裂解途径

Key words:  Aloe, HPLC-DAD-ESI-IT-TOF-MSⁿ, anthraquinone, anthrone, chromone, chemical constituents, fragmentation pathways

摘要:

为阐明中药库拉索芦荟(Aloe barbadensis)叶的汁液浓缩干燥物的化学成分,该研究采用HPLC-DAD-ESI-IT-TOF-MSⁿ技术,结合对照品对比和文献检索,对其进行系统的定性分析。以水(A)-乙腈(B)为流动相进行梯度洗脱,流速为1.0 mL·min^-1,质谱使用ESI离子源,采用负离子模式分析液质数据。结果表明:(1)首次阐明中药库拉索芦荟中蒽醌类(芦荟大黄素、大黄素甲醚、大黄素-8-O-β-D-吡喃葡萄糖苷)、蒽酮类(芦荟素A、芦荟糖苷A)、色酮类(芦荟新苷D、7-O-甲基芦荟新苷A、altechromone A、芦荟苦素、芦荟新苷G、芦荟新苷C)、α-吡喃酮类(芦荟宁A、芦荟宁B)四类成分的主要化合物的裂解途径。蒽醌类化合物的裂解途径以失去CO₂和CO为主,蒽酮类化合物的裂解途径以己糖苷的裂解和失去CO为主,色酮类化合物的裂解途径以己糖苷的裂解和酯基的水解为主,α-吡喃酮类的裂解途径主要包括己糖苷的裂解、CO₂和H₂O的丢失等。(2)共检测到168种化学成分,参考相关文献、数据库和对照品数据共鉴定/指认了其中的78种化学成分,包括3种蒽醌类成分、29种蒽酮类成分、35种色酮类成分、7种α-吡喃酮类成分、4种其他类成分; 78种化学成分中有23种为新发现的库拉索芦荟叶的化学成分,其中aloinoside D、isoeleutherin、ethylidene-aloenin等14种成分具有抗菌、抗炎或清除自由基等药理活性。该研究结果进一步丰富了中药库拉索芦荟的化学成分信息,为芦荟的药效物质基础研究及质量控制奠定了基础。

Abstract:

To clarify the chemical constituents of the traditional Chinese medicine Aloe made from Aloe barbadensis, i.e., the concentrated dry matter of the juice of the leaves of A. barbadensis, a systematic qualitative analysis of them was conducted using the technique of HPLC-DAD-ESI-IT-TOF-MSⁿ in conjunction with the comparison of reference compounds and literature search. The gradient elution was performed with water(A)-acetonitrile(B)as mobile phase at a flow rate of 1.0 mL·min^-1. The liquid chromatography-mass spectrometry data were acquired under alternate negative ion and positive ion detection mode using an ESI ion source. The structure elucidation of the chemical constituents was mainly based on negative ion mass spectrometry data. The results were as follows:(1)For the first time, the fragmentation pathways of anthraquinones(aloe-emodin, physcion, and emodin-8-O-β-D-glucoside), anthrones(aloin A, aloinoside A), chromones(aloeresin D, 7-O-methylaloeresin A, altechromone A, aloesin, aloeresin G, and aloeresin C), and α-pyranones(aloenin A, aloenin B)in Aloe made from A. barbadensis were clarified. The fragmentation pathway of anthraquinones was dominated by loss of CO₂ and CO, and that of anthrones was dominated by cleavage of hexosides and loss of CO. The fragmentation pathways of chromones was dominated by cleavage of hexosides and hydrolysis of the ester group, and that of α-pyranones was dominated by cleavage of hexosides and loss of CO₂ and H₂O.(2)A total of 168 chemical constituents of Aloe made from A. barbadensis were detected, and 78 of them were identified on the basis of reference compound comparison, literature retrieval, and chemical database(such as SciFinder)searching. The 78 compounds included 3 anthraquinones, 29 anthrones, 35 chromones, 7 α-pyranones and 4 other constituents. Twenty-three of 78 compounds were discovered in the leaves of A. barbadensis for the first time. Fourteen of 23 were newly discovered compounds, including aloinoside D, isoeleutherin, and ethylidene-aloenin, possessed antibacterial, anti-inflammatory, or free radical scavenging activities. The results of this study further enrich the information on the chemical constituents of the traditional Chinese medicine Aloe made from A. barbadensis, and lay a foundation for the study of the therapeutic material basis and quality control methods of Aloe.