@rabishchandra (Views are personal)
A group of researchers from Canada with the support of researchers from India (Coimbatore, Tamil Nadu) has detected contamination and substitution in forty four herbal products.
Today morning (6th November) when I was going through the print edition of The Economic Times, I found an interesting news item entitled as 'Bitter Pill: It's Just Rice & Soy and No More Herbal' (Author could not find the internet version of this article). After going through the report it was understood that a group of researchers tested forty four herbal supplements randomly and found that in one-third of them there was no trace of the plant material advertised on the bottle and instead it showed substitution of other plants like rice and soy.
To find out more about this, I searched for it on the internet. The same news was already reported by Anand O'Connor in International New York Times on 3rd November with the title - Herbal Supplements Are Often Not What They Seem. Here I found the link for the original published paper. The article was published in the mid of October in BMC Medicine .
The research article entitling 'DNA barcoding detects contamination and substitution in North American herbal products' is published by a group of scientists from University of Guelph, Canada and Bharathiar University, Coimbatore, India. They 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. Their laboratory 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. They found that 59% of the products tested contained DNA barcodes from plant species not listed on the labels. One-third of these also contained contaminants and or fillers not listed on the label. Product substitution occurred in 30 out of 44 of the products tested and only 2 out of 12 companies had products without any substitution, contamination or fillers. They mentioned that some of the contaminants they found pose serious health risks to consumers.
Although there are some findings which report the presence of heavy metals with regard to Botanicals from developing countries, this study about the contamination of herbal products from North America proves the failure of good manufacturing practices even in developed nations. Researchers suggest that herbal industry should embrace DNA barcoding for authenticating herbal products through testing of raw materials used in manufacturing products. Regulatory body should adopt this test model for the quality control of the herbal products.