Internal transcribed spacer 2 barcode: a good tool for identifying Acanthopanacis cortex.

Area of Science:

• Pharmacognosy and Molecular Biology
• Botanical identification using DNA markers

Background:

• Acanthopanacis cortex is a long-used medicinal herb.
• Potential safety issues arise from misidentification of Acanthopanacis cortex with similar herbs in markets due to historical and geographical factors.

Purpose of the Study:

• To evaluate the effectiveness of the internal transcribed spacer 2 (ITS2) DNA barcode for identifying Acanthopanacis cortex and its adulterants.
• To ensure the safety and quality of Acanthopanacis cortex in medicinal markets.

Main Methods:

• DNA extraction and sequencing of the ITS2 region from 69 samples across six species.
• Analysis using nearest distance, single-nucleotide polymorphisms (SNPs), and neighbor-joining (NJ) tree methods.
• Application of the Kimura-2-parameter model for genetic distance calculations.

Main Results:

• The ITS2 barcode demonstrated clear species discrimination, with minimum interspecific distances exceeding maximum intraspecific distances.
• Three stable SNPs were identified for differentiating Acanthopanacis cortex from closely related species.
• The NJ tree analysis successfully clustered Acanthopanacis cortex samples, distinguishing them from adulterants.
• ITS2 secondary structure analysis provided an additional layer for species identification.

Conclusions:

• The ITS2 DNA barcode is a reliable and effective tool for the accurate identification of Acanthopanacis cortex.
• DNA barcoding offers a convenient and powerful method for supervising medicinal markets and preventing the use of adulterated herbs.