大花序桉树皮化学成分分析及其抗氧化活性研究

Analysis of the Chemical Constituents of the Eucalyptus cloeziana Bark and Research on Its Antioxidative Activities

利用超高效液相色谱-串联四极杆静电场轨道阱高分辨质谱(UPLC-Q-EXACTIVE-MS)法快速分析大花序桉树皮抽提物的化学成分,同时测定其体外抗氧化活性,为其树皮资源的开发利用提供科学依据。采用ACQUITY UPLC BEH C18色谱柱(2.1 mm×50 mm×1.7μm),以0.1%甲酸水(A)-甲醇(B)流动相进行梯度洗脱,流速为0.3 mL/min;采用ESI离子源,在正负离子模式下扫描,根据高分辨质谱提供的准分子离子峰和二级离子碎片的精确分子质量信息,结合数据库和相关文献材料,从大花序桉树皮中鉴定出化学成分共26种,其中黄酮类2种、机酸类15种、三萜类1种、生物碱类2种、脂肪酸酰胺类6种;体外抗氧化试验结果表明,大花序桉树皮抽提物对DPPH、ABTS均有较好的清除能力,其IC50分别为60.02、76.94μg/mL。本研究建立的UPLC-Q-EXACTIVE-MS法能快速、准确、较全面地鉴定大花序桉树皮化学成分,所得的裂解规律可为其他同类化学成分鉴定提供参考;大花序桉树皮具有良好的抗氧化活性,可作为天然抗氧化活性物质来源。

The purpose of this study was to rapidly analyze and identify the chemical constituents of Eucalyptus cloeziana bark extract using ultra high performance liquid chromatography-quadrupole/exactive Orbitrap mass spectrometry(UPLC-Q-EXACTIVE-MS)and determine the vitro antioxidant activity of these compounds to provide a scientific basis for the exploi-tation of their bark resources.A Waters ACQUITY UPLC BEH C18 column(2.1 mm×50 mm×1.7μm)was used for gradient elution with 0.1%formic acid aqueous solution and methanol as the mobile phase at a 3.0 mL/min flow rate.The electrospray ion source(ESI)was used for mass spectrometry data in positive and negative ion modes.According to the accurate excimer ion peak and secondary mass spectral information provided by UPLC-Q-EXACTIVE-MS,a total of 26 compounds in Euca-lyptus cloeziana bark were identified or tentatively identified by conjunction with the relevant literature,which included two flavonoids,15 organic acids,one triterpene,two alkaloids,and six fatty acid amides.The in vitro antioxidant test results showed that the bark extract of E.cloeziana had good DPPH and ABTS scavenging abilities,with IC50 values of 60.02μg/mL and 76.94μg/mL,respectively.This study is the first to establish that the UPLC-Q-EXACTIVE-MS method is a rapid,accu-rate,and comprehensive method for identifying the chemical composition of the bark of E.cloeziana,and the resulting cleav-age pattern can provide a reference for the identification of other similar chemical components.However,E.cloeziana bark has good antioxidant activity and can be a natural source of active antioxidant substances.