Specific PCR Identification between Peucedanum praeruptorum and Angelica decursiva and Identification between Them and Adulterant Using DNA Barcode

Chemotaxonomic Classification of Peucedanum japonicum and Its Chemical Correlation with Peucedanum praeruptorum, Angelica decursiva, and Saposhnikovia divaricata by Liquid Chromatography Combined with Chemometrics

The roots of Peucedanum japonicum (Apiaceae) have been used as an alternative to the roots of Saposhnikovia divaricata (Apiaceae) to treat common cold-related symptoms in Korea. However, a variety of Peucedanum species, including the roots of P. praeruptorum or Angelica decursiva (=P. decursivum), have been used to treat phlegm-heat-induced symptoms in China. Hence, as there are differences in the medicinal application of P. japonicum roots between Korea and China, chemotaxonomic classification of P. japonicum was evaluated. Sixty samples derived from P. japonicum, P. praeruptorum, A. decursiva, and S. divaricata were phylogenetically identified using DNA barcoding tools, and chemotaxonomic correlations among the samples were evaluated using chromatographic profiling with chemometric analyses. P. japonicum samples were phylogenetically grouped into the same cluster as P. praeruptorum samples, followed by S. divaricata samples at the next cluster level, whereas A. decursiva samples were widely separated from the other species. Moreover, P. japonicum samples showed higher chemical correlations with P. praeruptorum samples or A. decursiva samples, but lower or negative chemical correlations with S. divaricata samples. These results demonstrate that P. japonicum is more genetically and chemically relevant to P. praeruptorum or A. decursiva and, accordingly, the medicinal application of P. japonicum might be closer to the therapeutic category of these two species than that of S. divaricata.

Rapid Identification of Peucedanum Praeruptorum Dunn and its Adulterants by Hand-Held near-Infrared Spectroscopy

Peucedanum praeruptorum Dunn (PPD) is a traditional Chinese medical herb of high medical and economic value. However, PPD is often pretended by inexpensive plants. To establish an integrated methodology using hand-held near-infrared spectroscopy (NIRS) combined with chemical pattern recognition techniques to identify adulterated PPD products. The standard normal variate (SNV) was used to preprocess the original near-infrared spectra. Principal component analysis (PCA), linear discriminant analysis (LDA), and partial least squares regression analysis (PLSDA) were used to construct the recognition models. PCA analysis could not correctly distinguish PPD from non-PPD. However, based on absorbance in the spectral region of 1,405-2,442 nm and SVN pretreatment, the accuracy of the LDA model was above 90% at identifying genuine PPD. Compared with the LDA method, the PLSDA model is more stable and reliable, and its model prediction accuracy was 93.4%. The combination of near-infrared spectroscopy and chemometric methods based on a hand-held near-infrared spectrometer is an efficient, non-destructive, and reliable method for validating traditional Chinese medicine PPD. It can be used for rapid identification and quality evaluation of PPD in the field, medicinal material markets, and points of sale.

Identification of Bupleurum (Apiaceae) seeds by allele-specific PCR based on ITS sequences

The traditional Chinese medicine Bupleuri radix (chaihu) is the dried roots of Bupleurum chinense and Bupleurum scorzonerifolium and many adulterants exist because of the differences in traditional understanding, medication habits and seed resources. Therefore, rapid and accurate identification methods for Bupleurum (Apiaceae) seeds are required. We analyzed the internal transcribed spacer (ITS) sequences of five common Bupleurum species to detect variations in them, including B. chinense, B. scorzonerifolium, B. marginatum var. stenophyllum, B. falcatum and B. smithii var.parvifolium. Based on single nucleotide polymorphisms (SNPs) in the ITS region, we designed five specific primer pairs and used these primers in an allele-specific PCR technique to establish a robust molecular identification method. The neighbor-joining (NJ) tree of ITS sequences showed that five Bupleurum species formed their own monophyly. Five specific primer pairs were designed and integrated into a specific PCR master mix and cycling conditions. The primer pair of BCF/R8 for B. chinense could amplify a specific identification band of 429 bp and the minimum detection limit of the 5 g mixture was about 5%; BSF/R11 for B. scorzonerifolium could amplify a specific 464 bp band and the minimum detection limit was about 5%; BMSF/R1 for B. marginatum var. stenophyllum could amplify a specific 344 bp band and the minimum detection limit was about 1%; BFF/R7 for B. falcatum could amplify a specific 137 bp band and the minimum detection limit was about 1%; BSPF/R1 for B. smithii var. parvifolium could amplify a specific 390 bp band. Subsequent analysis proved the reliable accuracy and good practicability of the five specific identification primers, indicating that the allele-specific primer PCR identification method can quickly identify Bupleurum seeds. The method elaborated in this study has the advantages of simple operation, good accuracy and high efficiency.

Inspecting the True Identity of Herbal Materials from Cynanchum Using ITS2 Barcode

Cynanchum is a large genus with some important medicinal species in China. The medicinal species in Cynanchum are easily confused, leading to potential safety risks. In this study, the internal transcribed spacer 2 (ITS2) barcode was used to discriminate the medicinal plants in Cynanchum. The identifying capability of ITS2 was assessed using the specific genetic divergence, BLAST1, neighbor-joining (NJ) tree, maximum-likelihood (ML) tree, and single-nucleotide polymorphism (SNP) methods. Results indicated that the intra-specific genetic divergences of Cynanchum species were lower than their inter-specific genetic divergences. Of the 87 samples from 17 species, ITS2 showed a high identification efficiency of 90.8 and 87.4% at the species level through BLAST1 and the nearest distance methods. NJ tree and ML tree also demonstrated the suitability of ITS2 to differentiate Cynanchum species. Meanwhile, a stable SNP was found, and it could accurately authenticate Cynanchum paniculatum and Cynanchum atratum. Furthermore, we collected 64 commercial samples from three commonly used herbal medicines and evaluated the capability of ITS2 to survey their authentication. Of these samples, Cynanchi Atrati Radix et Rhizoma (Baiwei) showed a potential safety problem, and all the 11 test samples were adulterants. In conclusion, ITS2 can distinguish medicinal species in Cynanchum effectively, and its application could greatly improve the identification efficiency and accuracy of commercial herbal medicines in this genus.