Molecular identification of Aucklandiae Radix, Vladimiriae Radix, Inulae Radix, Aristolochiae Radix and Kadsurae Radix using ITS2 barcode

In order to identify Aucklandiae Radix, Vladimiriae Radix, Inulae Radix, Aristolochiae Radix and Kadsurae Radix using ITS2 barcodes, genomic DNA from sixty samples was extracted and the ITS2 (internal transcribed spacer) regions were amplified and sequenced. The genetic distances were computed using MEGA 5.0 in accordance with the kimura 2-parameter (K2P) model and the neighbor-joining (NJ) phylogenetic tree was constructed. The results indicated that for Aucklandiae Radix (Aucklandia lappa), Vladimiriae Radix (Vladimiria souliei and V. souliei var. cinerea), Inulae Radix (Inula helenium), Aristolochiae Radix (Aristolochia debilis) and Kadsurae Radix (Kadsura longipedunculata), the intra-specific variation was smaller than inter-specific one. There are 162 variable sites among 272 bp after alignment of all ITS2 sequence haplotypes. For each species, the intra-specific genetic distances were also smaller than inter-specific one. Furthermore, the NJ tree strongly supported that Aucklandiae Radix, Vladimiriae Radix, Inulae Radix, Aristolochiae Radix and Kadsurae Radix can be differentiated. At the same time, V. souliei (Dolomiaea souliei) and V. souliei var. cinerea( D. souliei var. cinerea) belonging to Vladimiriae Radix were clearly identified. In conclusion, ITS2 barcode could be used to identify Aucklandiae Radix, Vladimiriae Radix, Inulae Radix, Aristolochiae Radix and Kadsurae Radix. Our study may provide a scientific foundation for clinical safe use of the traditional Chinese medicines.