板蓝根化学成分及抗氧化活性的研究

Chemical Constituents and Antioxidant Activity of Radix Isatidis

采用高效液相色谱-串联质谱法(HPLC-MS/MS)和直接进样的电喷雾串联质谱法(ESI-MS/MS)分析板蓝根乙酸乙酯提取物、正丁醇提取物和95%乙醇提取物的化学成分。同时,采用铁离子还原能力法(FRAP)评价板蓝根的抗氧化活性,并通过自由基清除能力法(DPPH)对FRAP法的测试结果进行验证。结果表明:在板蓝根乙酸乙酯提取物、正丁醇提取物和95%乙醇提取物中共鉴别出吲哚类、喹唑酮类、有机酸类、核苷类、嘌呤类、氨基酸类、黄酮类以及糖类等28个化合物。研究发现,板蓝根抗氧化活性部位主要集中在极性较低的化学组分中,吲哚类、喹唑酮类和有机酸类化合物是其主要的有效成分。该方法简便、快捷、灵敏,可为中药化学成分分析和抗氧化活性评价提供方法参考。

High performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） and electrospray ionization tandem mass spectrometry （ESI-MS/MS） were applied to analyze the chemical constituents from acetate, n-BuOH and 95% ethanol extracts of Radix Isatidis. The separation was performed on a Kromasil C18 column （4.6 mm×250 mm×5 μm） with gradient of 0.15% acetic acid/water and methanol as mobile phase with a flow rate of 0.8 mL/min at 25 ℃. The UV spectra of peaks were obtained by a diode array detector （DAD） under the detection wavelength at 254 nm and 265 nm. In order to get exact data of MS and MS2 spectra, the atmosphere pressure chemical ionization ion source （APCI） and electrospray ionization ion source （ESI） in positive and negative scan mode were utilized. Up to date, twenty-eight compounds are identified from the crude extracts, including indoles, quinazolinones, organic acids, nucleosides, purines, amino acids, flavones and carbohydrates. Meanwhile, the antioxidant activity of the extracts from Radix Isatidis were estimated by the ferric reducing antioxidant power （FRAP） and radical scavenging （DPPH） methods. The results of the antioxidant activities indicated that the compositions of antioxidant activity are mainly existed in the small polarity part. Indoles, quinazolinones, organic acids and porphyrins are the main antioxidative constituents of Radix Isatidis. This method is rapid and sensitive, which can be used for analyzing the chemical compositions and antioxidant activities of traditional Chinese medicine in the future.