GENEWATCH
 
UNCOVERING HERBAL FRAUD WITH DNA BARCODING
By CRG Staff
 

from GeneWatch 26-5
Nov-Dec 2013

When you buy medicine, you probably don't question whether it actually contains the active ingredients listed on the bottle. If you live in one of the world's more-developed countries, your government probably has a stringent enough drug approval process to prevent egregiously mislabeled medications from reaching the shelves, or at least to pull them from the shelves if mislabeling is identified. But what if you take herbal supplements? Who makes sure the ground-up leaves inside an Echinacea pill are really Echinacea and not, for example, an invasive weed which has been known to cause allergies and skin rashes? If you have a nut allergy, how do you know your Ginkgo biloba doesn't have, say, black walnut mixed in with it?

Herbal supplements are subject to much less regulatory oversight, and until recently, it would have been very difficult (and often practically impossible) to crack open a pill and determine which species were inside. But now, with the advent of DNA barcoding, researchers or regulators can do just that - and so far, it's not looking good for herbals.

A study published in the journal BMC Medicine this fall used DNA barcoding to test the authenticity of 44 herbal supplements from 12 companies. To do this, the lab (at University of Guelph in Canada) created an herbal barcode library for reference, then matched DNA barcodes from the supplements to those in the reference library. The researchers were able to collect enough DNA from 91% of the herbal products to determine which species were inside. They found that 59% of the products included DNA barcodes from species not listed on the label, and only two of the twelve companies had products which didn't include fillers, substitutes, or contaminants.

Some of the examples are astonishing. In addition to the Echinacea and Gingko biloba examples above (yes, those were both real), the researchers found two products labeled St. John's wort that contained no St. John's wort (one instead contained Alexandrian senna, a laxative); capsules that were supposed to contain dandelion also included grass, or contained no dandelion and instead only wheat and something in the banana family. Fully 9% of the products turned out to contain no trace of the herb listed on the label, only fillers and substitutes.

The University of Guelph laboratory that conducted this research is working on standardized testing procedures and a DNA barcode library for commercial herbal species which herbal supplement companies could use to accurately and inexpensively authenticate their products. Given the results so far, that might become standard practice in the herbal supplements industry sooner rather than later. 

See the full study at http://www.biomedcentral.com/1741-7015/11/222.

 
 
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