DNA barcoding of <i>Bacopa</i> species coupled with high-resolution melting analysis.

In Thailand, there are three species of<i> Bacopa</i>, namely, <i>B. monnieri</i>, <i>B. caroliniana</i> and <i>B. floribunda</i>. Among these <i>Bacopa</i> species, <i>B. monnieri</i> is the only medicinal species used for the treatment of cognitive impairment and improvement of cognitive abilities because of its bioactive constituents, bacoside A and B. However, due to the similar characteristics of plants, it is difficult to differentiate among related species, resulting in confusion during identification. For this reason, to ensure therapeutic quality for consumers, authentication is important. In this study, the three abovementioned <i>Bacopa</i> species were evaluated using barcoding coupled with high-resolution melting (Bar-HRM) analysis based on primers designed for the <i>trn</i>L-F sequences of the three species. The melting profiles of the <i>trn</i>L-F amplicons of <i>B. caroliniana</i> and <i>B. floribunda</i> were clearly different from the melting profile of the <i>trn</i>L-F amplicon from<i> B. monnieri</i>; thus, the species could be discriminated by Bar-HRM analysis. Bar-HRM was then used to authenticate commercial products in various forms. The melting curves of the six commercial samples indicated that all the tested products contained genuine <i>B. monnieri</i> species. This method provides an efficient and reliable authentication system for future commercial herbal products and offers a reference system for quality control.