DNA Barcoding Identification of Kadsurae Caulis and Spatholobi Caulis Based on Internal Transcribed Spacer 2 Region and Secondary Structure Prediction

BACKGROUND: Kadsurae Caulis and Spatholobi Caulis have very similar Chinese names. Their commodities were hard to distinguish because their stems were very alike after dried and processed. These two herbal drugs were often mixed in clinical use. OBJECTIVE: Authenticity assurance is crucial for quality control of herbal drugs. Therefore, it is essential to establish a method for identifying the two herbs. MATERIALS AND METHODS: In this paper, we used the DNA barcoding technology, based on the internal transcribed spacer 2 (ITS2) regions, to differentiate Kadsurae Caulis and Spatholobi Caulis. RESULTS: The ITS2 of these two herbs were very different. They were successfully differentiated using the DNA barcoding technique. CONCLUSIONS: DNA barcoding was a promising and reliable tool for the identification of medicinal plants. It can be a powerful complementary method for traditional authentication. SUMMARY: The internal transcribed spacer 2 (ITS2) regions between Kadsurae Caulis and Spatholobi Caulis varied considerably, totally 139 variable sites. Sample 1 was not Kadsurae Caulis as it labeled, but it should be Spatholobi Caulis in fact based on ITS2 region. The secondary structure can also separate Kadsurae Caulis and Spatholobi Caulis effectively. DNA barcoding provided an accurate and strong prove to identify these two herbs. Abbreviations used: CTAB: hexadecyltrimethylammonium bromide, DNA: deoxyribonucleic acid, ITS2:internal transcribed spacer 2, PCR: polymerase chain reaction