Use of a novel combination of multiplex PCR and DNA barcoding in assessing authenticity of ginseng products

Abstract

Ginseng (Panax sp.) is a medicinal plant used for its purported health benefits, primarily in East Asian countries. The COVID-19 pandemic led to a significant increase in sales of dietary supplements, including ginseng supplements, to purportedly support immune health and provide other health benefits. However, this heightened demand has subsequently increased the risk of adulteration in these dietary supplements. This study aimed to determine the efficacy of a novel combination of DNA barcoding and multiplex PCR to identify species in ginseng supplements. A total of 50 commercial ginseng supplements containing Panax ginseng, Panax quinquefolius, or Panax notoginseng were obtained from an online vendor. Two composite samples per product were subjected to DNA extraction followed by multiplex PCR and DNA barcoding with three genetic targets (i.e., rbcL, matK, and ITS2). Of the three DNA barcoding markers, ITS2 had the highest amplification success at 74%, and matK had the highest sequencing success at 60%. DNA barcoding alone identified species in 68% of products, while multiplex PCR had an overall 60% identification rate. The combination of both methods resulted in a 72% species identification rate. In addition to improving the overall identification rate, the combination of both methods allowed for greater species resolution and the detection of undeclared plant species. Future research should explore combining DNA-based methods with chemical-based approaches to improve ginseng detection capabilities and enable the quantification of undeclared adulterants.