Different geographical origins and species of Paris obtained from southwestern China were discriminated by near infrared (NIR) spectroscopy and high performance liquid chromatography (HPLC) combined with multivariate analysis. The NIR parameter settings were scanning (64 times), resolution (4 cm−1), scanning range (10000 cm−1∼4000 cm−1) and parallel collection (3 times). NIR spectrum was optimized by TQ 8.6 software, and the ranges 7455∼6852 cm−1 and 5973∼4007 cm−1 were selected according to the spectrum standard deviation. The contents of polyphyllin I, polyphyllin II, polyphyllin VI, and polyphyllin VII and total steroid saponins were detected by HPLC. The contents of chemical components data matrix and spectrum data matrix were integrated and analyzed by partial least squares discriminant analysis (PLS-DA). From the PLS-DA model of NIR spectrum, Paris samples were separated into three groups according to the different geographical origins. The R2X and Q2Y described accumulative contribution rates were 99.50% and 94.03% of the total variance, respectively. The PLS-DA model according to 12 species of Paris described 99.62% of the variation in X and predicted 95.23% in Y. The results of the contents of chemical components described differences among collections quantitatively. A multivariate statistical model of PLS-DA showed geographical origins of Paris had a much greater influence on Paris compared with species. NIR and HPLC combined with multivariate analysis could discriminate different geographical origins and different species. The quality of Paris showed regional dependence.
Dried sclerotium of Wolfiporia cocos (F.A. Wolf) Ryvarden & Gilb. is a traditional Chinese medicine. Its chemical components showed difference among geographical origins, which made it difficult to keep therapeutic potency consistent. The identification of the geographical origin of W. cocos is the fundamental prerequisite for its worldwide recognition and acceptance. Four variable selection methods were employed for near infrared spectroscopy (NIR) variable selection and the characteristic variables were screened for the establishment of Fisher function models in further identification of the origin of W. cocos from Yunnan, China. For the obvious differences between poriae cutis (fu-ling-pi in Chinese, or FLP) and the inner part (bai-fu-ling in Chinese, or BFL) of the sclerotia of W. cocos in the pattern space of principal component analysis (PCA), we established discriminant models for FLP and BFL separately. Through variable selection, the models were significant improved and also the models were simplified by using only a small part of the variables. The characteristic variables were screened (13 for BFL and 10 for FLP) to build Fisher discriminant function models and the validation results showed the models were reliable and effective. Additionally, the characteristic variables were interpreted.
Gentiana rigescens is a traditional Chinese medicine with efficacy in liver protection, as a cholagogic, anti-hyperglycemic, and anti-hypertension agent, and in relieving spasms and pain.
Gentiana rigescens is one of the most important traditional Chinese medicines because of its therapeutic effects in protecting the liver and promoting bile discharge, anti‐hypertension, and spasm and pain relief. To enhance quality control, a comprehensive assessment of G. rigescens from different geographic origins by Fourier‐transform infrared (FTIR) in combination with chemometrics was conducted. Through pretreatment by the second derivative, spectrum standard deviation and Monte Carlo uninformative variable elimination (MC‐UVE), the characteristic FTIR spectra were selected and an identification model of the different geographic origins of G. rigescens was built by partial least squares discriminant analysis (PLS‐DA). The validation results showed that the accuracy rates of the model were 100%, 97.22%, and 100% for samples from Yunnan, Guizhou, and Sichuan, respectively. On the basis of the correlation between characteristic spectral points and the contents of swertiamarin, gentiopicroside, sweroside, and loganic acid, quantitative models were established by partial least squares regression (PLSR). The measured and predicted values were not significantly different as assessed through the paired t test (p > 0.05). Additionally, the characteristic spectra were interpreted, and 93 common peaks were selected. FTIR analysis combined with chemometric methods could accurately identify the different geographic origins of G. rigescens and rapidly predict the content of swertiamarin, gentiopicroside, sweroside, and loganic acid, thus providing a comprehensive method of evaluating traditional Chinese medicines.
The concentrations of nine mineral elements were determined by atomic absorption spectroscopy in Gentiana rigescens from three zones (middle, southeast, and northwest zones) of Yunnan province in China. The average concentrations of mineral elements were found in the order K>Ca>Mg>Fe>Na>Zn>Cu>Cr>Se. Samples collected from the middle zone of Yunnan were enriched in Na (242.24 ± 50.80 mg/kg) and Mg (959.78 ± 54.60 mg/kg). However, materials from the southeast zone were particularly enriched in Ca (3,448.70 ± 749.82 mg/kg), but depleted in Se. Whereas those from the northwest zone were plentiful of K (2,746.89 ± 84.84 mg/kg), Fe (923.06 ± 127.52 mg/kg), Zn (261.38 ± 53.05 mg/kg), Cu (110.08 ± 46.23 mg/kg), and Se (53.99 ± 22.38 mg/kg).
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