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

Abstract

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.

A Systematic Study on DNA Barcoding of Medicinally Important Genus Epimedium L. (Berberidaceae)

“…Recently, DNA barcoding technique has been widely used for species discrimination. Up to now, matK , rbcL , psbA - trnH , internal transcribed spacer (ITS), and ITS2 are the most commonly used regions for DNA barcoding in plants [31,32,33,34]. In this study, we systematically evaluated the feasibility and identification efficiency of four generally acknowledged single loci, namely, rbcL , psbA - trnH , ITS, and ITS2, and their combinations to discriminate the Epimedium species distributed in China to identify the most suitable barcodes for genus Epimedium and provide effective information for the species identification of this genus.…”

Sixteen Years of DNA Barcoding in China: What Has Been Done? What Can Be Done?

“…For example, Li et al (2014) identified the herbal medicinal materials from Aristolochia using the matK, rbcL, psbA-trnH, and trnL-trnF DNA regions. Guo et al (2017) identified the herbal materials from Cynanchum using the ITS2 barcode; Gong et al (2018) constructed a DNA barcode reference library for "Nan Yao" (crude drugs mainly produced in or imported through tropical and subtropical China, especially the Lingnan region, i.e., the territories south of the Nanling Mountains) using ITS2; and Jiao et al (2018) identified the medicinal Polygonati Rhizoma (a traditional medicinal and edible product with Polygonatum polysaccharides, saponins, phenols, and flavonoids) efficiently and accurately using ITS2 and psbA-trnH sequences. This shows that the selection of molecular markers for plant groups in China still relies heavily on the combination of multiple markers.…”

Cynanchum paniculatum and Its Major Active Constituents for Inflammatory‐Related Diseases: A Review of Traditional Use, Multiple Pathway Modulations, and Clinical Applications

“…The medicinal species in Cynanchum are easily confused, leading to potential safety risks. Through the development of identification technology, researchers identified Cynanchi Atrati Radix et Rhizoma ( Baiwei in Chinese) showed a potential safety problem by discriminating 64 commercial samples of the medicinal plants [ 116 ]. By employing the internal transcribed spacer 2 (ITS2) barcode, researchers surveyed the authentication and greatly improved the identification efficiency and accuracy of commercial herbal medicines in the Cynanchum genus [ 13 , 114 , 116 ].…”

“…Through the development of identification technology, researchers identified Cynanchi Atrati Radix et Rhizoma ( Baiwei in Chinese) showed a potential safety problem by discriminating 64 commercial samples of the medicinal plants [ 116 ]. By employing the internal transcribed spacer 2 (ITS2) barcode, researchers surveyed the authentication and greatly improved the identification efficiency and accuracy of commercial herbal medicines in the Cynanchum genus [ 13 , 114 , 116 ]. In 2006, Deng et al reported quick and easy identification of paeonol content by the microwave-assisted extraction and headspace single-drop microextraction (MAE-HS-SDME) method for quality monitoring for the two herbal medications of Cynanchum paniculatum and Paeonia suffruticosa [ 13 , 114 , 117 ].…”