Assessment of the Authenticity of Herbal Dietary Supplements: Comparison of chemical and DNA barcoding methods

Dietary supplements are a growing, multi-billion dollar, global business. The consumer perceptions that these products are natural and safe, may prevent disease, may replace prescription medicines, or may make up for a poor diet, have led to their growing popularity. At the same time, some of these businesses have been criticized for problems related to, among others, poor quality control, safety, misbranding, and adulteration. Investigations have shown that some of these products were found to be unauthentic as they lack chemical markers associated with the particular plant. Other investigations have also found that botanical supplements were devoid of the labeled ingredients based on not finding their genetic signature according to DNA barcoding. These investigations have brought into the discussion the suitability of traditional DNA barcoding methods for analyzing finished dietary supplements. In our study, we investigated five popular botanical ingredients (Valerian, soy isoflavones, yohimbe, St. John's wort and Ginkgo) for their authenticity by chemical and DNA barcoding methods. The results of the HPLC quantification of the chemical markers with respect to the label claims are discussed and compared to the results of the DNA barcoding study. Based on the findings, the advantages and drawbacks of the two methods are discussed.