ABSTRACT
Rhei Radix et Rhizoma is one of the most used medicinal materials in China. Its original species are Rheum palmatum, Rh. tanguticum, and Rh. officinale. Rhei Radix et Rhizoma derived from different original species are significantly different in their active ingredients and pharmacological effects. To develop an accurate, rapid, and specific identification method, we obtained the chloroplast genomes of the three original species by Illumina Novaseq sequencing. We designed specific DNA barcodes from the hypervariable regions, which can accurately identify the three original species. The experimental results showed that the total length of the chloroplast genomes of Rh. tanguticum, Rh. officinale and Rh. palmatum were 161 039 bp, 161 093 bp, and 161 136 bp, respectively. All the three genomes were represented as typical quadripartite structures. A total of 131 genes, including 86 protein-coding genes, 37 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes were identified from each chloroplast genome. Five pairs of primers based on the hypervariable regions were designed to efficiently amplify 42 samples. Results confirmed that five hypervariable regions, rps16-trnQ, psaA-ycf3, psbE-petL, ndhF-rpl32, and trnT-trnL, can be used as specific DNA barcodes for the identification of Rh. tanguticum, Rh. officinale, and Rh. palmatum. These results provided genetic information for further species identification of Rhei Radix et Rhizoma, and improve the safety of this clinical medication as well as standardize the market for Rhei Radix et Rhizoma.
ABSTRACT
Adulterants and counterfeits were found in some of the commercial traditional Chinese medicine (TCM) decoctions in Hongjin Xiaojie Jiaonang, Hongjin Xiaojie Pian, and Chaihuang Keli during the national drug sampling inspection. However, it was difficult to determine the species of the adulterants and counterfeits by conventional testing methods. Therefore, a total of 184 samples of the TCM decoctions and raw materials belong to the prescriptions of above mentioned traditional Chinese patent medicines, including Bupleuri Radix, Bajiaolian, Heimayi, and Shufuchong, were collected and authenticated by DNA barcoding technology. 111 ITS2 sequences were obtained from 115 commercial TCM decoctions and raw materials of Bupleuri Radix, among which 71 were Bupleurum chinense, three were B. scorzonerifolium, and 31 were closely related species in the same genus. In addition, counterfeits derived from different genera, such as Ailanthus altissima (one sample), Saposhnikovia divaricate (two samples), and Solidago decurrens (three samples), were also detected. 21 ITS2 sequences were obtained from 22 commercial TCM raw materials of Bajiaolian, among which 15 were Diphylleia sinensis and six were Dysosma versipellis and other species in genus Dysosma. For 22 Heimayi samples, PCR amplification of COI sequence was failed due to genomic DNA degradation. Among 38 Shufuchong samples, 24 COI sequences were obtained and only nine of them were the genuine species (Armadillidium vulgare) recorded in the Chinese Pharmacopoeia, 11 were Porcellio laevis, two were Mongoloniscus sinensis, and two samples could not be identified due to the limitation of database. This study demonstrates that DNA barcoding technology is suitable for the species authentication of the decoctions of traditional Chinese patent medicine prescription. It is a conductive way for the establishment of traceability system for the whole TCM industrial chain.
ABSTRACT
Rhei Radix et Rhizoma is a kind of commonly used Chinese medicinal materials. Due to the overharvesting, the wild resource is endangering. Large market demand caused severely adulterant of commercial Rhei Radix et Rhizoma medicinal materials and decoction pieces. This manuscript reviewed the advances of the original species authentication in the industrial chain of Rhei Radix et Rhizoma during the latest decade, including characteristics and microscopic features, phytochemical analysis on anthraquinones, and molecular authentication based on DNA barcoding. Accordingly, an original species authentication route for the industrial chain of Rhei Radix et Rhizoma was summarized:(1)the identification of seeds and seedlings by DNA barcoding;(2) the selection of high variable sites based on the chloroplast genome;(3)biomonitoring of the Rhei Radix et Rhizoma medicinal materials and decoction pieces by two-dimensional DNA barcode;(4)traceability of Chinese patent medicines by third-generation sequencing. In conclusion, the combination of molecular identification and traditional identification methods provides a new idea for the identification of the original species of Rhei Radix et Rhizoma in the industrial chain and a essential guidance for the research of drug safety and efficacy of Rhei Radix et Rhizoma.
Subject(s)
Animals , Anthraquinones , Drugs, Chinese Herbal , Plant Roots , Rheum , RhizomeABSTRACT
Although the guiding principles for molecular identification of traditional Chinese medicines (TCM) using DNA barcoding have been recorded in the Chinese Pharmacopoeia, there is still a lack of systematic research on its application to commercial TCM decoctions. In this study, a total of 212 commercial TCM decoctions derived from different medicinal parts such as root and rhizome, fruit and seed, herb, flower, leaf, cortex, and caulis were collected to verify applicability and accuracy of the method. DNA barcodes were successfully obtained from 75.9% (161/212) of the samples, while other samples failed to be amplified due to genomic DNA degradation. Among the 161 samples, 85.7% of them were identified as recorded species in the Chinese Pharmacopoeia (2020 edition). In addition, 14 samples could be identified as species recorded in the Chinese Pharmacopoeia and their closely related species in the same genus. Morphological identification for the unconfirmed samples showed that eight were genuine species and three were adulterants, while the other three were unidentifiable due to lack of morphological characteristics. Furthermore, the DNA barcodes of seven samples accurately mapped to the sequences of adulterants. Remarkably, counterfeit products were detected in two samples. These results demonstrate that DNA barcoding is suitable for the identification of commercial TCM decoctions. The method can effectively detect adulterants and is appropriate for use throughout the industrial chain of TCM production and distribution, and by the supervisory agencies as well.