Abstract

Internal transcribed spacer 2 (ITS2) is known as a good sequence of DNA molecular barcoding. In this study, the authors authenticated Campsis Flos and its common adulterants based on ITS2 sequence. Campsis Flos has been used in traditional Chinese medicine for many years as a blood activator to promote menstruation. Among its adulterants in the market, the most common are the flowers of Paulownia tomentosa, Hibiscus syriacus and Rhododendron molle. To discriminate Campsis Flos from these adulterants and control its quality, safety and efficacy, the total genomic DNA was extracted from the leaves of Campsis grandiflora, Campsis radicans, and their common adulterants. The internal transcribed spacer 2 (ITS2) of ribosomal DNA was sequenced after PCR amplifying. A neighbor-joining (NJ) tree was constructed using MEGA 6.0. The ITS2 secondary structure was predicted by an ITS2 web server. The results showed that the ITS2 sequence lengths of C. grandiflora, C. radicans, and P. tomentosa were 246–248, 246, and 229–233 bp, respectively. The ITS2 sequence lengths of H. syriacus, H. syriacus L. f. var. syriacus f. amplissimus, and R. molle were all 230 bp. The ITS2 secondary structure of Campsis Flos was then effectively distinguished from its adulterants. In conclusion, barcode ITS2 sequence could be used to rapidly and accurately identify Campsis Flos from its adulterants to promote quality control and standardization.

Key words: DNA molecular barcoding, ITS2 sequence, Campsis Flos, identification.