Abstract:

To address the challenge of accurately distinguishing Uyghur medicinal herb pingna (Mentha spicata) from its easily confused substitute, M. canadensis due to their morphological similarities, and to ensure medication safety, a multi-dimensional identification method was established in this study. Ten batches of pingna and five batches of M. canadensis samples were collected. DNA barcoding (ITS sequence) was used for molecular identification, combined with thin-layer chromatography (TLC) and gas chromatography (GC) for the qualitative and quantitative analysis of L-carvone, the characteristic component of M. spicata. The ITS phylogenetic tree clearly separated the two species into two distinct clusters. TLC results showed that all M. spicata samples contained the characteristic spot of L-carvone, which was absent in all M. canadensis samples. GC analysis confirmed that the L-carvone content in M. spicata ranged from 0.21 to 1.62 mg/g, while it was undetected in M. canadensis. The multidimensional identification system integrating DNA barcoding and chemical characteristic profiling established in this study enables rapid and accurate cross-verification of M. spicata and M. canadensis. This reliable method provides crucial technical support for quality control and standardization of M. spicata.

Key words: pingna (Mentha spicata), DNA barcoding, ITS sequence, thin-layer chromatography, gas chromatography, identification