红外光谱技术在滇龙胆栽培方式选择上的应用

摘要

Medicinal plants are the resources of traditional Chinese medicines (TCM), and selecting appropriate cultivation method is conductive to guarantee the quality of TCM from the source.In this research, in order to select optimal cultivation method for the Gentiana rigescens, Fourier transform infrared (FTIR) spectroscopy combined with chemometrics was used for analyzing the G.rigescens which were cultivated through sowing in drill, broadcast sowing, transplanting after root pruning, cutting and transplanting after pruning.The results were as follows: (1) Original FTIR spectra of G.rigescens from different cultivation methods had some differences in shape, position and intensity of peak.After preprocessed with the wavelet denoising, the spectral data were analyzed by partial least squares discriminant analysis (PLS-DA), and samples with different cultivation methods could be distinguished well.The results of PLS-DA demonstrated that samples with the same cultivation method could be grouped well.It suggested that the difference between chemical constituents and content of G.rigescens with the same cultivation method were relatively low.The G.rigescens through sowing (sowing in drill and broadcast sowing) were relatively close, so were the G.rigescens through transplanting (root pruning, cutting and pruning).However, samples by sowing were far from that of transplanting.It showed that cultivation method influence the accumulation of chemical constituents of G.rigescens.(2) The total content of four main components in G.rigescens was decreased in the order of pruning, root pruning, broadcast sowing, sowing in drill and cutting, and was significantly higher in samples through pruning than that of others except for root pruning (P<0.05).The G.rigescens through pruning could obtain optimum quality.(3) Based on the reference data performed by liquid chromatography, orthogonal signal correction-partial least squares (OSC-PLS) models were established for predicting the content of gentiopicroside, loganic acid, swertiamarin and sweroside in G.rigescens from different cultivation methods.Both of the determination coefficients (R2) of calibration and validation sets were above 0.90, root mean square error of estimation (RMSEE), root mean squared error of cross-validation (RMSECV) and RMSEP were below 1.65.It demonstrated that the models showed good linear correlation and prediction accuracy.It provides the reference for the popularization and application of infrared spectroscopy in the field of TCM.%该研究采用傅里叶变换红外光谱结合化学计量学,对条播、撒播、剪根后移栽、扦插和剪枝后移栽的滇龙胆进行了分析,以筛选滇龙胆的最佳栽培方式.结果表明:(1)不同栽培方式的滇龙胆原始谱图在峰形、峰位和峰强上有一定差异;用小波去噪法对光谱进行优化处理并进行偏最小二乘判别分析(Partial least squares discriminant analysis, PLS-DA),能较好地区分不同栽培方式的滇龙胆样品,PLS-DA二维得分图显示同一栽培方式的样品聚在一起,表明相同栽培方式的滇龙胆化学组成和含量差异较小;播种滇龙胆样品(条播和撒播)距离较近,移栽滇龙胆样品(剪根、扦插和剪枝)距离较近,而播种和移栽滇龙胆样品距离较远,表明栽培方式对滇龙胆化学成分的积累有影响.(2)滇龙胆四种主要成分总含量大小依次是剪枝>剪根>撒播>条播>扦插,除剪根后移栽,剪枝后移栽滇龙胆中四种主要成分总含量显著高于其他栽培方式下的滇龙胆(P<0.05),剪枝后移栽滇龙胆质量最佳.(3)以液相数据为参考值,采用正交信号校正-偏最小二乘回归模型预测不同栽培模式滇龙胆中龙胆苦苷、马钱苷酸、獐牙菜苦苷和当药苷的含量.校正集和验证集的决定系数(R2)均大于0.90,校正均方根误差、交叉验证均方差和预测均方根误差均小于1.65,模型相关性和预测效果好,该方法对红外光谱分析在中药领域的推广应用提供了参考.