DNA barcodes of bacopa plants found in Thailand

Abstract

Bacopa monnieri (Family Plantaginaceae) commonly known as ‘Brahmi’ or ‘Prom-mi’ is a medicinal plant used for a remedy of cognitive impairment and intelligence in Ayurvedic Materia Medica and Thai traditional medicine. Bacoside A, the major active constituents, is classified as triterpenoid saponin. In Thailand, there are three Bacopa species including Prom mi [B. monnieri (L.) Wettst.], Lan pailin [B. caroliniana (Walter) B. L. Rob.] and Phak sam lan [B. floribunda (R. Br.) Wettst.]. Since the dried or powdered raw materials are difficult to identify plant species, this study attempted to develop a method for accurate identification of Bacopa spp. found in Thailand by using DNA barcode. Six DNA regions, ITS, matK, rbcL, ycf1, psbA-trnH and trnL-F, were proposed for the study. DNA barcodes of ycf1 and trnL-F coupled with high resolution melting (HRM) analysis were successfully used for species identification. The characteristic of specific melting temperature (Tm) was able to distinguish among the Bacopa species. This is the first study using DNA barcode techniques to differentiate Bacopa spp. and identify the medicinal plant B. monnieri from the related species. Moreover, DNA barcodes are useful asset for standardization and quality control purposes.