Identification of traditional medicine "Fructus Arctii" by nuclear ribosomal DNA ITS sequences

Abstract

To identify the traditional medicine Fructus Arctii from its adulterants by ITS. Twenty-six samples of the different Fructus Arctii materials and 10 samples of the adulterants of the fruits of A. tomentosum, Onopordum acantium, Silybum marianum, and Amorpha fruticosa were collected. The total DNA of the samples were extracted, amplified cloned and sequenced. ITS sequences were obtained from 26 samples respectively, there were Fructus Arctii 641 bp, A. tomentosum 641 bp, Onopordum acantium 639 bp, Silybum marianum 630-631 bp, Amorpha fruticosa 625-626 bp, which were registered in the GenBank. The similarity in ITS sequences between Fructus Arctii and the adulterants was less than 95%. In contrast, the similarity between any pair of Fructus Arctii was greater than 99%. The similarity was 98.29%-99.22% between Fructus Arctii and A. tomentosum. Phylogeny tree reconstruction using UPGMA analysis based on ITS nucleotide sequences can effectively distinguish Fructus Arctii from adulterants. ITS sequences can be used as a reliable molecular marker for the identification of Fructus Arctii.