Testing of the supplements was conducted using DNA barcoding, a technique that uses specific DNA sequences to look for markers that indicate a specific plant species. This technique has had much success in determining animal and plant material authenticity and inclusion of potential adulterants.
However, these techniques work best on material where the DNA is likely to be there intact. As pointed out by the critics of this investigation, many of the herbal supplements sold are highly processed, and this processing may degrade the DNA to a point where it will not be detected.
In DNA barcoding of medicinal plant material for identification (Techen, etal 2014 Current Opinion in Biotechnology Volume 25, Pages 103–110):
The isolation of pure, high molecular weight DNA is critical for the successful application of molecular methods. This can be quite a challenge since in processed medicinal plant material the DNA is often highly degraded or the plant material contains high amounts of polysaccharides, polyphenols and other secondary metabolites, such as, alkaloids and flavonoids. Various commercial kits and modified traditional methods are available to yield in good quality DNA from raw and powdered medicinal plant material, herbarium specimens, capsules, tablets, or tinctures for downstream applicationsIn DNA barcoding as a new tool for food traceability (Galimberti et al. 2013, Food Research International Volume 50, Issue 1, Pages 55–63):
DNA is normally more resistant to industrial processes than other molecules, such as proteins (Martinez et al., 2003), and DNA fingerprinting methods can be successfully used in identifying animal or plant materials, even when in small traces (Bottero and Dalmasso, 2011, Costa et al., 2010, Kesmen et al., 2007, Mane et al., 2009, Martin et al., 2009 and Soares et al., 2010). Nonetheless, food processing causes chemical and physical alterations, degradation and fragmentation being the most common effects (Bauer, Weller, Hammes, & Hertel, 2003). DNA integrity largely influences the effectiveness of molecular methodologies (Hellberg and Morrisey, 2011, Meusnier et al., 2008 and Pafundo et al., 2007). DNA barcoding can have two advantages if compared to DNA fingerprinting approaches: i) it requires the amplification of a short DNA fragment (hence there is a lower risk of fragmentation), and ii) it is based on mitochondrial or plastidial genome (more preserved during processing).
From the National Institutes of Health website:
Dietary supplements are not required to be standardized in the United States. In fact, no legal or regulatory definition exists for standardization in the United States as it applies to botanical dietary supplements. Because of this, the term "standardization" may mean many different things. Some manufacturers use the term standardization incorrectly to refer to uniform manufacturing practices; following a recipe is not sufficient for a product to be called standardized. Therefore, the presence of the word "standardized" on a supplement label does not necessarily indicate product quality.
In 2007, the FDA issued Good Manufacturing Practices (GMPs) for dietary supplements, a set of requirements and expectations by which dietary supplements must be manufactured, prepared, and stored to ensure quality. Manufacturers are now expected to guarantee the identity, purity, strength, and composition of their dietary supplements. For example, the GMPs aim to prevent the inclusion of the wrong ingredients, the addition of too much or too little of a dietary ingredient, the possibility of contamination (by pesticides, heavy metals such as lead, bacteria, etc.), and the improper packaging and labeling of a product.
Like other dietary supplements, botanicals are not required by federal law to be tested for safety and effectiveness before they are marketed, so the amount of scientific evidence available for various botanical ingredients varies widely. Some botanicals have been evaluated in scientific studies. For example, research shows that St. John's wort may be useful for short-term treatment of mild to moderate depression. Other botanical dietary supplements need more study to determine their value.
The dietary supplement industry has estimated sales of $6 billion, part of a $13 billion dietary supplements industry. This investigation, while questionable in terms of methodology, may trigger further investigation into whether or not the dietary supplement industry is following questionable practices.
CBS/APFebruary 8, 2015, 3:59 PM
http://www.cbsnews.com/news/herbal-supplements-industry-lashes-out-at-fraud-claims/
Herbal supplements industry lashes out at fraud claims
ALBANY, N.Y. - DNA barcoding has exposed some infamous cases of food fraud, like cheap catfish sold as pricey grouper and expensive "sheep's milk" cheese that was really made from cow's milk.
But can it tell if a pill touted as an energy-booster contains ginseng or is just a mix of rice powder and pine?
Some scientists say yes, while industry groups and some independent experts say DNA testing alone is inadequate for analyzing botanical products that have gone through a lot of processing from leaf to tablet.