Research Of Simultaneous And Rapid Identification Of Three Species Of Ephedra Authorized In The Chinese Pharmacopoeia Using Near-infrared Spectroscopy

Ephedrae herba are used in the treatment of anemofrigid cold,chest tightness,asthma and wind edema.The dried herbaceous stems of Ephedra sinica Stapf,Ephedra intermedia Schrenk et C.A.Mey.or Ephedra equisetina Bge.have been recorded as the Ephedrae herba in the Chinese Pharmacopoeia,European Pharmacopoeia and Japanese Pharmacopoeia.In this study,a near-infrared(NIR)spectroscopy combined with the chemometrics for identifying the three species of Ephedra authorized in the Chinese pharmacopoeia was established.The three species of Ephedra authorized in the Chinese pharmacopoeia can be simultaneously and rapidly identified by using this method.OBJECTIVE:To identify simultaneously and rapidly three species of Ephedra authorized in the Chinese pharmacopoeia using near-infrared(NIR)spectroscopy.METHODS:1.Measurements of NIR spectra of Ephedra authorized in the Chinese pharmacopoeia and adulterant speciesThe Ephedra authorized in the Chinese pharmacopoeia,including Ephedra sinica Stapf,Ephedra intermedia Schrenk et C.A.Mey.and Ephedra equisetina Bge.,and the adulterant species,including Ephedra likiangensis Florin,one species of plant similar in morphology to Ephedra sinica Stapf,Artemisiae scopariae herba,Coptidis rhizoma and Astragali radix,were pulverized and through the sieve of 80 mesh.The spectra were measured with Antaris II Fourier transform NIR analyzer.The measurement conditions: the scan range of 10000 – 4000 cm-1,resolution of 4 cm-1 and scans of 64.2.Calibration and validation of the discriminant analysis model for identification of the three species of Ephedra authorized in the Chinese pharmacopoeiaThe same spectral features,which differ from various adulterant species,were extracted from different species of Ephedra authorized in the Chinese pharmacopoeia using Fourier transform NIR diffuse reflectance spectroscopy combined with chemometric techniques.The discriminant analysis(DA)model were built and validated for identifying the different species of Ephedra authorized in the Chinese pharmacopoeia from the various adulterant species.3.Calibration and validation of the counterpropagation artificial neural network model for identification of the three species of Ephedra authorized in the Chinese pharmacopoeiaThe same spectral features,which differ from various adulterant species,were extracted from different species of Ephedra authorized in the Chinese pharmacopoeia using Fourier transform NIR diffuse reflectance spectroscopy combined with chemometric techniques.The counterpropagation artificial neural network(CP-ANN)model were built and validated for identifying the different species of Ephedra authorized in the Chinese pharmacopoeia from the various adulterant species.The performances of two models were compared.RESULTS:1.The prediction accuracy of the established DA model was 100.0% for both calibration and validation.2.The prediction accuracy of the established CP-ANN model was 100.0% for all of calibration,cross-validation and validation.3.Although the two models have the same prediction accuracy,the nonlinear CP-ANN model is slightly better than the linear DA model because it uses less principal components(PCs).CONCLUSION:The three species of Ephedra authorized in the Chinese pharmacopoeia can be simultaneously and rapidly identified by using the established NIR spectroscopy.