ABSTRACT
Objective: In order to study the application of DNA barcoding in the authentication of Chinese patent medicines, Sanqi Tablets were used as the object to investigate the applicability, specificity and precision of this method. Methods: Fifteen batches of commercially available Sanqi Tablet samples were collected. The conditions of DNA extraction for Sanqi Tablet had been first investigated, and the DNA was used for testing the applicability of the methods such as PCR amplification, sequence acquisition, and species authentication in the principles for molecular identification of traditional Chinese materia medica using DNA barcoding. The specificity and reproducibility of DNA barcoding in identification of Sanqi Tablets and its adulterations from the roots of Panax notoginseng, P. ginseng and P. quinquefolius were also studied. Results: The Sanqi Tablet sample with an amount of sampling to be 100 mg and a water bath at 56 ℃ for 8 h gave an average concentration of 60.7 ng/μL and then the PCR amplification, sequence acquisition and species assignment were all successful. The ITS2 sequences of P. notoginseng, P. ginseng and P. quinquefolius were all 230 bp in length, and there were seven stable SNP loci between P. notoginseng and P. ginseng, P. notoginseng and P. quinquefolius. ITS2 sequences could be successfully obtained from lab-made and the adulterated Sanqi Tablets, and the Sanger sequencing chromatograms of different ratios of P. notoginseng and P. ginseng mixtures, P. notoginseng and P. quinquefolius mixtures had heterozygous peaks with corresponding peak height ratio at SNP positions. The repeatability, intermediate precision and reproducibility were all in line with the requirements of “General Regulation 9101” in the Chinese Pharmacopoeia. Conclusion: The ITS2 sequence can stably and accurately authenticate the raw materials of Sanqi Tablets with substantial specificity and precision. The DNA barcoding identification method of Sanqi Tablets will provide a new technical tool for ensuring the safety of Sanqi Tablets in clinical medications, and provide reference for the identification of other single-herb products documented in the Chinese Pharmacopoeia.
ABSTRACT
Objective:To establish a molecular identification method for Bupleurum chinense seeds based on ribosomal DNA internal transcribed spacer (ITS) sequence, ensuring the species authenticity of the cultivated seeds of B. chinense. Method:A total of 59 seeds samples of B. chinense and its main cultivated species, marketed B. chinense were collected. The effect of different sampling amounts and different water bath conditions on DNA extraction quality of the seeds was investigated, a DNA extraction method for seeds of Bupleurum was established. Their ITS sequences were obtained by polymerase chain reaction (PCR) and bidirectional sequencing. In addition, 34 ITS sequences of main cultivated Bupleurum species, such as B. chinense, B. scorzonerifolium, B. falcatum and B. smithii, were downloaded from GenBank to enrich identification database of B. chinense seeds. The neighbor-joining (NJ) dendrogram were constructed by MEGA-X 10.0.5 software to investigate the the species identification ability of ITS sequences for B. chinense seeds. And DNA barcoding identification of marketed B. chinense seeds was conducted based on BLAST method and NJ dendrogram method. Result:In total, 59 ITS sequences were obtained. ITS sequences of B. chinense could be divided into six haplotypes, including seven variable sites. The NJ dendrogram indicated that all the haplotypes of B. chinense could form independent branches, which could be distinguished from other cultivated species of Bupleurum in the collected samples, and possessed the ability to identify species of B. chinense seeds. Based on ITS sequence barcoding identification, 3 of the 19 marketed B. chinense seeds were B. falcatum with a counterfeit rate of 15.8%. Conclusion:DNA barcoding technology based on ITS sequence can accurately and reliably identify B. chinense seeds and its adulterants, providing reference for the standardization construction of Chinese medicinal materials seeds.