Identification of Verbena officinalis based on ITS sequence analysis and RAPD-derived molecular markers.

Verbenae herba is a widely used drug and consists of the aerial parts of Verbena officinalis (Verbenaceae). Until now, the identification has been performed based on morphological and phytochemical analyses, which are not reliable enough to distinguish Verbena officinalis from other relevant species of the genus Verbena. Hence, impurities and adulterants, negatively influencing the therapeutic effect of the drug, may remain undetected. In an attempt to generate an accurate authentication method we used two different DNA-based approaches: comparison of ITS sequences and molecular markers (RAPD). Both approaches generally enabled discrimination of V. officinalis from the rest of the genus despite the intraspecific variation existing within V. officinalis. The application of the two independent methods, supporting each other, increases the security of identification. For better reproducibility and faster analysis, however, a SCAR marker and primers for HRM were derived from the RAPD results. The SCAR marker could distinguish V. officinalis from all other verbena species except its closest relative V. hastata, while discrimination of V. officinalis even from V. hastata was unproblematic with HRM.