Study On Differentiation F Swertia Davidii Franch With Four Species In The Swertia And Their Response Of Active Components To Ecological Factors

Swertia davidii Franch.is known to possess heat-clearing and detoxifying properties.At tujia area,S.davidii was usually used to clear lung thermal and treat jaundice,acute enteritis and bacillary dysentery and so on.It is extremely difficult to discriminate different species according to the morphological characteristics,due to the appearance of S.davidii is similar to other species of the same genus.S.davidii is distributed in Hunan,Hubei,Sichuan province and other regions in China,which quality is different from place to place.Therefore,for ensuring accuracy and availability of using S.davidii,it is important to establish the methods of discriminating S.davidii with closely relative species and to discover which factors would affect the quality difference of S.davidii from different regions.In this study,Fourier transform infrared,Ultra performance liquid chromatography and Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with chemometrics and metabolites methods were used to discriminate S.davidii and relative species.The relationship was studied between chemical components and ecological factors of different habitats of S.davidii.It was found that three methods could be used to the species discrimination of S.davidii and the four species of Swertia genus.There were obvious differences in the quality of S.davidii for different habitats,which is the best quality in S.davidii of Chongqing.The major results as follows:(1)To realize the accurate discrimination of the plants in Swertia by Fourier transform infrared(FTIR)spectroscopy and chemometrics.The original infrared spectra data from different parts(roots,stems,leaves)of all the 543 samples from S.davidii.S.mileensis,S.punicea,S.angustifolia and S.cincta were collected and preprocessed by multiplicative scatter correction(MSC),standard normal variate(SNV),Savitzky-Golay filter(SG),first derivative(1D),second derivative(2D),third derivative(3D).The five species of Swertia could accurately distinguish by PLS-DA and SVM models that were established by spectra data of all parts.The data which were processed by MSC+SG+2D have showed the best classification.(2)Discriminate 5 species Swertia plants by data fusion of FTIR and UPLC.We compared the original spectrum of samples.Hierarchical cluster analysis(HCA)and random forest(RF)were used to analyze the data.HCA could reflect the classification and genetic relationship of S.leducii and its wild relatives.The other 4 species excepting S.punicea were correctly classified and its total accuracy rate reached 93.1%.S.punicea,S.cincta and S.davidii had closed relationship with S.leducii while S.angustifolia was relative far.Comparing the FTIR,UPLC,low-level data fusion and mid-level data fusion,the number of error samples in classification of RF analysis were 1,5,1 and 0,respectively.In the RF models,the best classification of mid-level data fusion with none error samples was better than other data matrix.(3)A metabolomics method for the geographical origin discrimination of Swertia and different metabolites analysis was established based on Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-QTOF-MS).Five species of Swertia were successfully distinguished by principal component analysis(PCA)and then the 7 markers from different plant were identified.It was concluded that the metabolomics method can be used for the discrimination of Swertia species and the identification of the whole component.(4)UPLC was used to determination the contents of 3 secoiridoids(swertiamarin,gentiopicrioside,sweroside)and xanthones(mangiferin)in S.davidii from Hunan,Hubei,Sichuan and other regions.Using the world climate database,ecological factors data such as temperature,precipitation were obtained.In addition,the effects of ecological factors on these active components of S.davidii were studied by correlation analysis.There were significant differences among active ingredients of S.davidii from different areas,and the contents of swertiamarin,gentiopicrioside,mangiferin of S.davidii in Chongqin were the highest.The contents of in different areas of S.davidii were in the order of swertiamarin > gentiopicrioside > mangiferin > sweroside.Besides that,the content of swertiamarin appeared significant positive correlation with the amount of gentiopicrioside.The chemical constituents,such as swertiamain,mangiferin and gentiopicrioside of S.davidii,were significantly correlated with ecological factors.The main ecological factors for affecting the contents of active components in S.davidii was precipitation of driest month.