Chemometric Study Of Gentiana Rigescens Based On Chemical Fingerprint

The growing environments of medicinal plants are complicated,which lead to unstable medicinal quality.This problem has hindered the further development and utilization of this industry.The traditional identification methods are main observation of appearance and microscopic character.However,these approaches are subjective and inaccurate,which are insufficient for quality control.In view of the overall quality,many instruments and analytical techniques have played a more and more important role on the establishment of quality control system of medicinal plants.Fingerprint technique is able to create a qualitative and quantitative description of chemical profile,by which can detect the internal quality and treatment functions.Especially,spectroscopic and chromatographic methods are common and effective strategies.The former can elaborate the metabolic character overall and the latter can determinate the special active compounds in plants.The complementary information can provide the strong evidence for quality control of medicinal plants.Gentiana rigescens is one of the Chinese traditional medicines,which has the functions of eliminating damp-heat,quenching the fire of the liver and gall bladder.This species is mainly distributed in southwestern region of China.In this study,in order to discriminate and evaluate the G.rigescens material based on different producing areas,medicinal parts and growing years,ultraviolet-visible spectroscopy,Fourier transform infrared spectroscopy and high performance liquid chromatography,in combination of principal component analysis,partial least square discriminant analysis,partial least squares regression and support vector machine,were applied to analyze the chemical fingerprint characteristics,to describe the chemometrics classification features,and to determinate the active compounds.This study can provide a referee for quality control of this species.This paper is composed of 5 sections.Section 1 is about the discrimination of wild G.rigescens source from different producing areas on Yunnan-Kweichow Plateau based on Fourier transform infrared and chemometrics.Section 2 is about the feasibility of Fourier transform infrared technique for rapid measurement of main iridoid glycosides in this species.In Section 3,based on data fusion strategy,ultraviolet-visible and Fourier transform infrared spectroscopies further improve the discrimination accurate of G.rigescens source from different producing areas based on partial least square discriminant analysis and support vector machine models.Section 4 is about the discrimination and evaluation of cultivated G.rigescens materials from different medicinal parts and growing years qualitatively and quantitatively based on Fourier transform infrared and high performance liquid chromatography methods.Section 5 is a review about the application of ultraviolet,infrared spectroscopies and high performance liquid chromatography techniques for quality control of medicinal plants.1)The Fourier transform infrared characteristic peaks of wild G.rigescens from different producing areas are similar.Their absorbance are subtle different.The absorption peaks of 1610,1459,1375,1268,1075 cm-1 may be related to esters,phenols and terpene compounds.Principal component analysis result indicates that the quality of G.rigescens from Yunnan and Guizhou Province is different,which may be caused by elevation.Based on partial least square discriminant analysis and support vector machine models,G.rigescens from different producing areas were discriminated successfully and the accuracies of test set are 97.6% and 100%,respectively.The performance of non-linear classification method of support vector machine is better than linear method of partial least square discriminant analysis.2)Regarding high performance liquid chromatography as standard method,Fourier transform infrared spectroscopy,in combination of partial least squares regression model,are applied to determinate the gentiopicroside and total four iridoids(gentiopicroside,swertiamarin,sweroside and loganic acid)in wild and cultivated G.rigescens from different producing areas successfully,based on derivative algorithm and multiplicative scatter correction.The coefficient of determination is higher than 0.8.The root mean square error of estimation,root mean square error of cross validation and root mean square error of prediction are lower than 8 mg/g.The residual predictive deviations is higher than 2.Both models are reliable and robust.3)This section has reported the potential for chemometric characterization of G.rigescens from different producing areas using two rapid and low-cost spectroscopic techniques of ultraviolet-visible and Fourier transform infrared spectroscopies,individually and jointly.Comparatively,data fusion strategy can improve the discrimination performance obviously.In particular,the mid-level data fusion can provide the best results by selecting important variance from different data matrixes,with 100% correct classification of test samples by both partial least square discriminant analysis and support vector machine techniques.4)Selecting cultivated G.rigescens material as studied objective,high performance liquid chromatography and Fourier transform infrared techniques are applied to describe qualitative and quantitative characteristics of this species from different medicinal parts and growing years.High performance liquid chromatography data shows that accumulations of four iridoids(gentiopicroside,swertiamarin,sweroside and loganic acid)in 1-,2-and 3-year G.rigescens have obvious difference.After pretreatment of second derivative,Fourier transform infrared can discriminate the G.rigescens samples based on different medicinal parts and growing years successfully.In addition,based on selection of 1800-800 cm-1 band,the prediction performance of gentiopicroside was improved further.