Liu Yang, Wang Xiaoyue, Wang Lili, Chen Xiaochen, Pang Xiaohui, Han Jianping
Institute of Medicinal Plant Development, Chinese Academy of Medicinal Science and Peking Union Medicinal College Beijing, China.
Front Plant Sci. 2016 Mar 18;7:319. doi: 10.3389/fpls.2016.00319. eCollection 2016.
American ginseng (derived from Panax quinquefolius) is one of the most widely used medicinal herbs in the world. Because of its high price and increasing demand, there are many adulterants on the market. The proposed internal transcribed spacer 2 (ITS2) has been used to identify raw medicinal materials, but it is not suitable for the identification of Chinese patent medicine ingredients. Therefore, a short barcode for the identification of processed American ginseng and its corresponding Chinese patent medicines would be profitable. In this study, 94 samples of American ginseng and Asian ginseng were collected from all over the world. The ITS2 region was sequenced, and a nucleotide signature was developed based on one single nucleotide polymorphism (SNP) site unique to American ginseng. The nucleotide signature (atcactcctt tgcgggagtc gaggcgg) consists of 27 bases over the length of the ITS2 sequence (420 bp). Furthermore, we also designed primer pairs to amplify the nucleotide signature; the specific primer pair 4F/4R has been found to be unique to the ginseng species and capable of amplifying the nucleotide signatures from Chinese patent medicines and decoctions. We used the nucleotide signature method to inspect ginseng products in Chinese patent medicines; 24 batches of Chinese patent medicine from stores in Beijing were amplified and sequenced successfully. Using the double peaks at the SNP sites of the nucleotide signature, 5 batches were found to be counterfeits, and 2 batches were found to contain adulterants. Thus, this nucleotide signature, with only 27 bp, has broadened the application of DNA barcoding in identification of decoctions, Chinese patent medicines and other ginseng products with degraded DNA. This method can rapidly identify ginseng products and could also be developed as an on-site detection method.
西洋参（来源于五加科人参属植物西洋参）是世界上使用最广泛的草药之一。由于其价格高昂且需求不断增加，市场上存在许多掺假品。已提出的内转录间隔区2（ITS2）已用于鉴定生药材，但不适用于中成药成分的鉴定。因此，一个用于鉴定加工后的西洋参及其相应中成药的短条形码将具有重要意义。在本研究中，从世界各地收集了94个西洋参和亚洲人参样本。对ITS2区域进行了测序，并基于西洋参特有的一个单核苷酸多态性（SNP）位点开发了一个核苷酸特征序列。该核苷酸特征序列（atcactcctt tgcgggagtc gaggcgg）在ITS2序列长度（420 bp）上由27个碱基组成。此外，我们还设计了引物对来扩增该核苷酸特征序列；已发现特异性引物对4F/4R对人参属物种具有特异性，能够从中成药和汤剂中扩增出核苷酸特征序列。我们使用核苷酸特征序列方法检测中成药中的人参产品；成功扩增并测序了来自北京商店的24批次中成药。利用核苷酸特征序列SNP位点处的双峰，发现5批次为假冒品，2批次含有掺假物。因此，这个仅27 bp的核苷酸特征序列拓宽了DNA条形码在鉴定汤剂、中成药和其他DNA降解的人参产品中的应用。该方法能够快速鉴定人参产品，还可开发成为一种现场检测方法。
