Herbal medicine is popular. Consumers seem to be attracted by the notion that they are natural – and if it’s natural, it must be safe!!! But do we really know what is in the product that we might be buying? A recently published analytical study aimed to investigate herbal product integrity and authenticity with the goal of protecting consumers from health risks associated with product substitution and contamination.
The researchers used DNA barcoding to conduct a blind test of the authenticity for (i) 44 herbal products representing 12 companies and 30 different species of herbs, and (ii) 50 leaf samples collected from 42 herbal species. They also assembled the first standard reference material (SRM) herbal barcode library from 100 herbal species of known provenance that were used to identify the unknown herbal products and leaf samples.
DNA barcodes from 91% of the herbal products and all leaf samples could be recovered. 59% of the products tested contained DNA barcodes from plant species not listed on the labels. 48% of the products could be authenticated but one-third of these also contained contaminants and or fillers not listed on the label. Product substitution occurred in 30 of the 44 products tested and only 2 of the 12 companies sold products without any substitution, contamination or fillers. Some of the contaminants we found pose serious health risks to consumers.
Based on these findings, the authors drew the following conclusions: Most of the herbal products tested were of poor quality, including considerable product substitution, contamination and use of fillers. These activities dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them. We suggest that the herbal industry should embrace DNA barcoding for authenticating herbal products through testing of raw materials used in manufacturing products. The use of an SRM DNA herbal barcode library for testing bulk materials could provide a method for ‘best practices’ in the manufacturing of herbal products. This would provide consumers with safe, high quality herbal products.
These findings are fairly alarming. I have previously blogged about the fact that herbal products are far to often adulterated or contaminated. Now it seems that we have to add to this list of dangers the substitution of the herbal ingredient with a presumably less expensive but potentially toxic herb that should not legally be there at all.