农林复合系统滇龙胆茎叶化学计量特征研究

以农林复合系统种植的滇龙胆(Gentiana rigescens Franch.ex Hemsl.)为材料,采用高效液相色谱法建立不同栽培系统滇龙胆茎、叶的色谱指纹图谱,并测定其主要活性成分马钱苷酸、獐牙菜苦苷、龙胆苦苷和当药苷含量,研究不同栽培系统滇龙胆茎、叶化学计量特征。采用相关性分析、指纹图谱相似度分析、偏最小二乘判别分析(PLS-DA)、变量投影重要性准则(VIP)等方法进行化学数据分析。结果显示,滇龙胆主要活性成分马钱苷酸含量为(1.85±0.92)mg/g~(7.43±7.64)mg/g,獐牙菜苦苷含量为(1.03±0.17)mg/g~(1.58±0.50)mg/g,龙胆苦苷含量为(15.28±11.34)mg/g~(24.59±7.84)mg/g,当药苷含量为(4.10±1.64)mg/g~(31.67±22.70)mg/g,且叶片中4种活性成分的总含量高于茎;不同栽培系统中,与尼泊尔桤木间作的滇龙胆茎、叶活性成分总含量最高,而与核桃间作的滇龙胆茎、叶活性成分总含量最低。相关性分析显示,植株相同部位和不同部位间的环烯醚萜和裂环烯醚萜含量呈显著(P0.05)或极显著(P0.01)正相关。指纹图谱相似度分析表明,不同栽培系统滇龙胆茎指纹图谱相似度介于0.989~0.992之间、叶指纹图谱相似度为0.988~0.996,相同部位样品化学成分种类相似。PLS-DA分析结果表明,茎和叶片整体化学计量特征具有明显差异;单作及林药间作的样品被区分为不同类群,不同间作模式下滇龙胆茎、叶化学成分具显著差异,叶片高效液相色谱指纹图谱可用于区分不同栽培系统滇龙胆样品。本研究结果可为农林复合系统滇龙胆有效成分含量研究及滇龙胆资源的合理开发利用提供科学依据。

Chemometric Analysis of the Stem and Leaf of Gentiana rigescens in Agroforestry Systems

A method for HPLC fingerprinting of the aerial parts of Gentiana rigescens Franch. ex Hemsl. in agroforestry and monoculture systems was established. Contents of the main bioactive compounds, such as loganic acid, swertiamarin, gentiopicroside and sweroside, were determined. Variations in the chemometric characteristics of the stems and leaves under different cultivation systems were investigated, with correlation analysis, similarity analysis, partial least squares discriminant analysis (PLS-DA) and variable importance in the projection (VIP) analysis used to investigate these variations. Quantitative analysis showed that gentiopicroside, swertiamarin, loganic acid and sweroside contents ranged from (15.28±11.34) mg/g to (24.59±7.84) mg/g, (4.10±1.64) mg/g to (31.67±22.70) mg/g, (1.85±0.92) mg/g to (7.43±7.64) mg/g, and (1.03±0.17) mg/g to (1.58±0.50) mg/g, respectively. Total contents of the four bioactive compounds in leaves were higher than those in stems. Total content of the four bioactive compounds in the aerial part was the highest in the plant intercropped with Alnus nepalensis D. Don and was the lowest in the plant intercropped with Juglans regia L.. Correlation analysis showed that the variation in iridoid and secoiridoid content had significant (P < 0.05) or very significant (P < 0.01) positive correlation in the same part and in different parts, respectively. Similarities of the stem samples ranged from 0.989 to 0.992. Similarities of the leaf samples ranged from 0.988 to 0.996. The chemical constituents in stems and leaves were similar. However, the contents of those compounds were different. PLS-DA analysis showed that the chemometric characteristics of the stems and leaves were very different. Samples collected from different cultivation systems were classified as different groups. Chemical compounds in the leaves were more affected by the cultivation system than those in the stems. These results provide useful information for the study of agroforestry systems of G. rigescens Franch. ex Hemsl. and sustainable use of medicinal materials.