Internal transcribed spacer sequence-based identification and phylogenic relationship of I-Tiao-Gung originating from Flemingia and Glycine (Leguminosae) in Taiwan

Botanical root of Flemingia and Glycine of Leguminosae is used as a traditional Chinese medicine material “I-Tiao-Gung” in Taiwan. It is widely used in both traditional Chinese medicine and folk remedies for the treatment of rheumatism, arthropathy, leukorrhea, menalgia, menopausal syndrome, and chronic nephritis, and the improvement of bone mineral density. The quasi root of Glycine tomentella and Glycine tabacina is substituted and used by some off-shore island users, and it is also known as I-Tiao-Gung. Thus, the establishment of an effective method to distinguish the herb from alternative species is a critical issue. In this study, internal transcribed spacer (ITS) region-based analysis was used to ascertain the phylogenetic relationship among the indigenous four Flemingia species and two Glycine species. The length of the ITS regions among the six species ranged from 595 bp to 622 bp and the GC ratio in ITS (ITS 1 + 5.8S + ITS 2) regions ranged from 57.17% to 58.86%. The molecular phylogenetic trees were constructed and indicated that Flemingia species and Glycine species were separated into two clusters. These results indicate that ITS regions can be used as a molecular marker to differentiate the four Flemingia species and two Glycine species.