世界中医药

目的：运用Internal Transcribed Spacer 2(ITS2)条形码对半枝莲及其混伪品进行鉴别研究，为该药材的安全用药提供依据。方法：提取样品基因组DNA，对ITS2序列进行PCR扩增和双向测序，所得序列经CodonCode Aligner V5.0.2.0拼接，采用MEGA6.0软件进行序列比对，计算种内和种间遗传距离。采用最近距离法(Nearest Distance)和构建邻接树(NJ Tree)分析ITS2条形码对半枝莲的鉴定能力。结果：半枝莲ITS2序列种内遗传距离为0~0.008 4，与其混伪品半边莲、韩信草和荔枝草的种间遗传距离分别为0.354 7~0.369 6、0.044 2~0.054 2、0.271 9~0.301 8。半枝莲种内最大遗传距离小于其与混伪品的种间最小遗传距离，表明ITS2条形码可以准确鉴定半枝莲与其混伪品。基于ITS2序列构建的NJ树也可将半枝莲及其混伪品明显区分开。结论：ITS2序列可以快速、准确鉴别半枝莲与其混伪品，是鉴别半枝莲、保障其药材质量的有效条形码。

English Summary:

To discriminate betweenScutellariabarbata and its adulterants using ITS2 barcode to provide evidence for its clinic safety.Methods:The DNA was extracted from the samples and the second internal transcribed spacer(ITS2)was amplified and sequenced.Sequence assembly was performed using the CodonCode AlignerV5.0.2.0.The genetic distances and variable sites of ITS2 region were analyzed using MEGA6.0 after sequence alignment.Nearest distance and neighbor-joining tree(NJ-tree)methods were used to test the identification efficiency of the ITS2 barcode.Results:The intraspecific genetic distances ofS.barbata were 0~0.0084，while the interspecific genetic distances between S.barbata and its adulterants were 0.3547~0.3696,0.0442~0.0542，and 0.2719~0.3018，respectively.The maximum intraspecific genetic distance of S.barbata was lower than the minimum interspecific genetic distance between S.barbataand its adulterants，which indicates that ITS2 barcode could discriminate S.barbata and its adulterants accurately.The NJ tree based on ITS2 sequences also reveals that S.barbata and its adulterants could be obviously identified.Conclusion:S.barbata could be accurately distinguished from its adulterants using ITS2.The ITS2 region is an efficient barcode to guarantee the quality of medicines.

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