Identification of commercial Bupleuri Radix and its adulterants based on ITS2 barcode / 中草药

ABSTRACT

Objective DNA barcoding technology, a molecular identification method, is applied to distinguishing Bupleuri Radix from its adulterants in order to ensure the quality and clinical curative effect. Methods In this study, the internal transcribed spacer 2 (ITS2) regions of 85 samples were amplified by PCR and sequenced bi-directionally. Obtained sequences were assembled using CodonCode Aligner. The genetic distances were computed by MEGA 6.0 in accordance with the kimura 2-parameter (K2P) model and the phylogenetic tree was constructed by Neighbor-joining (NJ) method. Moreover, the secondary structure of ITS2 was predicted using ITS2 database websites. Results The intra-specific genetic distances were smaller than inter-specific ones in ITS2 regions of Bupleuri Radix. NJ tree and secondary structure results could distinctly differentiate quality product and adulterants. Only 64.7% of the 85 samples were in accordance with the requirements of Chinese Pharmacopoeia. Conclusion ITS2 sequence can accurately and reliably identify the authenticity of Bupleuri Radix and could provide a new technique to ensure clinical safety of this traditional Chinese medicine.