DNA identification method that can work on extracts detailed in study
In the paper, written by researchers from two Chinese research institutes along with Steven Newmaster, PhD, and Subramanyam Ragupathy, PhD, of the University of Guelph in Canada, the authors detailed the development of an identification method for Lonicerae japonicae Flos. The botanical, which goes by common names such as Japanese honeysuckle or Jinyinhua, is a common component of many Chinese patent medicines (CPMs). In general, the authors noted that traditional medicines are suffering from a rising tide of adulteration. The authors cite research that shows that 30% of TCM preparations sold in China may be adulterated, whereas another source showed that more than 70% of traditional medicines sold in Brazil were adulterated in some way.
Spiking with cheaper CGA sources
TCM preparations can often be highly complex, and the adulteration picture for Lonicerae japonicae Flos is complex, too. The popularity of the herb, which is rich in chlorogenic acid (CGA), means it suffers from widespread adulteration, according to the authors. Some unethical suppliers use cheaper species that also contain CGA but which have different chemical properties in other regards, according to the paper. The authors said Lonicerae japonicae Flos can be adulterated with, “Eucommiae Folium (E. ulmoides Oliv; Duzhongye) or Lonicerae Flos (Shanyinhua). Eucommiae Folium is derived from a completely different genera, and Lonicerae Flos can be derived from 4 different species including L. marantha (syn. L. fulvotomentosa), L. confusa, L. hypoglauca, and L. macranthoides. Lonicerae Flos is much cheaper than Lonicerae japonicae Flos. According to the theory of traditional Chinese medicine characteristics, Eucommiae Folium and Lonicerae japonicae Flos have totally different pharmacology, so the two herbal materials should be clearly distinguished.”
Follow-on to DNA barcoding
DNA barcoding has been put forward as a method for positive botanical identification, but the authors, in concert with many other experts in the industry, noted its drawbacks in that it relies on relatively intact strands of DNA, which may be difficult to find in materials after they have been processed and is not present in sufficiently intact form or in sufficient quantity in most extracts.
The newer technology, which is being developed through the NHP Research Alliance centered at the University of Guelph, builds on two components: Using a ‘nucleotide signature’ that is unique to the target species but is much shorter than a common DNA, and an easy to use device that should make uptake of the approach in industry easier.
“We are developing standard operating protocols (SOPS) at the NHP Research Alliance that will be validated, published, and shared with the NHP (natural health products) community. We have a very good working relationship with USP who is interested in receiving these SOPs and the co-development of robust standard biological reference materials (SBRM) for NHPs. We are developing this technology to run on biotechnology that is relatively cheap and can delver results on-site in realt time (TRU-ID certified via a cellular connection) in less than an hour,” Newmaster told NutraIngredients-USA.
Newmaster said more information on the technology will be presented at the American Herbal Products Association’s upcoming Botanical Congress. The one-day event will take place on Friday, Sept. 29 in Las Vegas after the conclusion of the SupplySide West trade show.
Approach successfully identifies widespread adulteration
“Our research presented here is focused on developing a contemporary molecular diagnostic tool for testing authentic Lonicerae japonicae Flos (L. japonica Thunb.; Jinyinhua) ingredients in NHPs. The goal of this study was to develop a short nucleotide signature for E. ulmoides and a SNP double peak detection method for Lonicerae Flos to distinguish the adulterant in the Lonicera extracts and CPMs,” the authors of the study wrote.
The study authors tested 24 extracts and 47 CPMs. Only 17% of the extracts and 22% of the CPMs were found to be free of adulteration. Furthermore, the paper added to the verification of the nucleotide signature method which was detailed for identification of American ginseng in a paper written by some of the same Chinese authors in 2016.
Newmaster said it is still very early days for the new ID technology, and much work still needs to be done for its wider application and acceptance. But he said that it does help fill in some of the gaps and criticisms of standard DNA barcoding.
“Barcoding is older technology of which we published numerous seminal scientific papers and book chapters between 2003-2013. This research provides a good stepping stone for more advanced molecular diagnostic tools that overcome many of the previous problems associated with testing NHPs.Although we do need to do this type of research for every species, we can attain this goal with a focused R&D team and that is the goal of the NHP Research Alliance,” Newmaster said.
Source: Science Reports
“Derivative Technology of DNA Barcoding (Nucleotide Signature and SNP Double Peak Methods) Detects Adulterants and Substitution in Chinese Patent Medicines”
Published online 2017 Jul 19. doi: 10.1038/s41598-017-05892-y
Authors: Gao Z, Liu Y, Wang X, et al.