DNA barcoding for the discrimination of Uncaria gambir and its closely related species using internal transcribed spacer genes

Abstract

Background: Uncaria gambir is one Uncaria species that exclusively grows in Indonesia. The phytochemical constituents of this species have been widely explored and its extracts are used as traditional medicine. However, the relationship between Uncaria gambir and other Uncaria species is still unknown. DNA barcoding was used in this study to reveal this relationship. Methods: Genomic DNA was isolated from four main cultivated variants of Uncaria gambir species in Indonesia. ITS primer was used to amplify the specific gene region. Genetic distance analysis was carried out on Uncaria gambir and 12 other Uncaria species. A phylogenetic tree was created to determine the relationship among Uncaria species using the maximum likelihood method. Results: The ITS primer successfully amplified the ITS region in Uncaria gambir. Genetic distance and phylogenetic tree analyses showed that Uncaria gambir has a close relationship with Uncaria scandens, Uncaria yunnanensis, and Uncaria macrophylla which is also indicated by Interspecific distance analysis. Conclusions: Although the DNA barcoding gap is absent in genetic distance analysis, the phylogenetic tree analysis from the ITS region can differentiate Uncaria gambir from other Uncaria species.