Identification of medicinal Atractylodes based on ITS sequences of nrDNA.

Dried rhizomes of five species of Atractylodes (A. japonica, A. macrocephala, A. lancea, A. chinensis, and A. koreana), Compositae, have been used as crude drugs mainly for the treatment of stomach disorders and for their diuretic properties in Chinese and Japanese traditional medicines. The identification of the botanical origins of these crude drugs is generally difficult from their morphological and chemical features only. In this study, for identification with more reliable, nuclear ribosomal DNA (nrDNA), internal transcribed spacer (ITS) regions of five species of medicinal Atractylodes were sequenced. As a result, specific ITS genotypes were recognized by each species. The four species (A. japonica, A. macrocephala, A. lancea, and A. chinensis) prescribed in Chinese and Japanese Pharmacopoeias as botanical origins of crude Atractylodes drugs could be distinguished by their ITS sequences because they had difference genotypes on the ITS sequences. However, the genotype of A. koreana was the same as that of A. chinensis. Additionally, hybrids between A. lancea and A. chinensis were also recognized as nucleotide additives on their ITS sequences. In this study, several morphological characteristics were researched by their genotype, too. As this result, the hybrids recognized from the genetic analysis had intermediate morphological characteristics between A. lancea and A. chinensis. It was also recognized that A. lancea and A. chinensis except for their hybrids were significant differences. It is therefore suggested that ITS sequences of nrDNA would be useful for the identification of the crude drugs derived from Atractylodes species and their interspecific hybridizations.