基于HPLC-ECD研究牡荆叶抗氧化的谱-效关系

Spectrum-effect relationship of antioxidant activity in Vitex negundo var. cannabifolia leaves based on HPLC-ECD

关键词:  牡荆叶, HPLC, 电化学检测, 抗氧化, 谱-效关系, 总酚, 总黄酮

Key words:  Vitex negundo var. cannabifolia leaves, HPLC, electrochemical detection, antioxidation, spectrum-effect relationship, total phenolics, total flavonoids

摘要:

为研究牡荆叶指纹图谱与抗氧化活性的谱-效关系,该研究首先建立了18批牡荆叶的高效液相色谱-电化学检测法(HPLC-ECD)指纹图谱,并对不同来源牡荆叶药材进行聚类分析; 鉴定主要酚类化合物并测定其含量; 分析牡荆叶的总酚和总黄酮含量,采用DPPH自由基清除法、ABTS自由基清除法、氧自由基吸收能力法及铁离子还原能力法考察其体外抗氧化活性,通过皮尔逊相关分析、灰度关联分析及偏最小二乘回归分析法研究牡荆叶的谱-效关系。结果表明:(1)牡荆叶的指纹图谱标定21个共有峰,共指认出10个峰,其含量顺序为绿原酸>异荭草苷>木犀草苷>异牡荆素>异绿原酸A>异绿原酸C>原儿茶酸>荭草苷>异绿原酸B>新绿原酸; 不同产地样品间相似性较高,相似度结果为0.816～0.983。(2)系统聚类分析显示,样品含量对分类有一定影响,不同来源样品被分为3类,其中南北方样品存在一定差异。(3)牡荆叶中总酚和总黄酮的含量分别为15.82～61.83 mg·g^-1和27.85～157.65 mg·g^-1,样品均具不同程度的抗氧化活性。(4)谱-效关系表明,牡荆叶的抗氧化活性是多种化合物协同作用的结果,峰9(异荭草苷)、峰4和峰5(绿原酸)等化合物对牡荆叶药材抗氧化活性的贡献最大。牡荆叶具有较好的抗氧化活性,其中主要的活性指标是异荭草苷和绿原酸。该研究结果可为牡荆叶抗氧化活性成分的筛选及其质量控制提供参考依据。

Abstract:

In order to study the spectrum-effect relationship between fingerprint and antioxidant activity of the leaves of Vitex negundo var. cannabifolia, the fingerprints of 18 batches of V. negundo var. cannabifolia leaves were established by high performance liquid chromatography-electrochemical detection(HPLC-ECD), and the cluster analysis of medicinal materials from different sources was performed simultaneously. The main phenolic compounds from V. negundo var. cannabifolia leaves were identified and determined. The contents of total phenolics and total flavonoids in V. negundo var. cannabifolia leaves were analyzed, and the antioxidant activities in vitro were evaluated by the methods of DPPH radical scavenging capacity, ABTS radical scavenging capacity, oxygen radical absorbance capacity and ferric ion reducing ability power. The spectrum-effect relationships of V. negundo var. cannabifolia leaves were analyzed by Pearson correlation analysis, gray relational analysis and partial least square regression analysis. The results were as follows:(1)The fingerprints of V. negundo var. cannabifolia leaves were established with 21 common peaks and a total of 10 peaks were identified. The order of content was chlorogenic acid > isoorientin > luteoloside > isovitexin > isochlorogenic acid A > isochlorogenic acid C > protocatechuic acid > orientin > isochlorogenic acid B > neochlorogenic acid. The similarity among the samples from different producing areas was high, and the values were ranged from 0.816 to 0.983.(2)The results of the cluster analysis showed that the content of the compounds had a certain influence on the classification and the samples from different sources were divided into three categories, among which the samples from the south and the north were different.(3)The contents of total phenolics and total flavonoids in V. negundo var. cannabifolia leaves were 15.82 to 61.83 mg·g^-1 and 27.85 to 157.65 mg·g^-1, respectively, and the antioxidant activity of all samples from V. negundo var. cannabifolia leaves existed differences.(4)The spectrum-effect relationship indicated that the antioxidant activity of V. negundo var. cannabifolia leaves was the result of the synergistic effect of many compounds, and compounds such as peak 9(isoorientin), peak 4 and peak 5(chlorogenic acid)made the greatest contribution to the antioxidant activity of V. negundo var. cannabifolia leaves. V. negundo var. cannabifolia has good antioxidant activity, and the main activity indexes are isoorientin and chlorogenic acid. This study can provide a reference basis for the screening and quality control of antioxidant components in V. negundo var. cannabifolia.