The applications and limitations of DNA markers in authenticating herbal materials
Refereed conference paper presented and published in conference proceedings

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AbstractBackground: DNA barcoding is now a widely used approach for the identification of biological specimens to the level of species and discovery of cryptic species. Through improvement on extraction protocols and primer design, herbal species can now be identified in decoctions and commercial products. Nevertheless, our studies have shown that DNA markers have several limitations that influence the success rate and accuracy of sequencing.

Results: The first shortcoming is the inadequate resolving power of DNA barcodes in some taxa. After analyzing seven DNA loci, including rbcL, Atpf, trnH–psbA, rpl36–rps8, ITS, trnL–F, and 5S rRNA, of the Gentiana taxa, only the latter two were able to discriminate closely related species G. triflora, G. scabra, and G. manushruica. In the study of Acontium, 19 taxa were clustered into 10 groups based on trnH–psbA, while the two most commonly used medicinal species, A. carmchaeli and A. kusnezoffii, could not be differentiated definitely. The second shortcoming is the difficulty in amplifying DNA barcodes across a broad range of taxa by universal primers. Alignment analysis revealed that there were 3–4 different nucleotides between the universal primer for (Atpf 3F Kim f) and the sequences of 17 taxa in the genus Gentiana, and 4 out of 10 samples of Gentiana could be not amplified. The third issue is the amplicon size of DNA for highly degraded or processed samples. Only short PCR products of about 100 bp were found in Panax ginseng decoction boiled for 2 h. In such cases, a mini-barcode may be employed to enhance the success rate. The fourth problem is amplification of the contaminant species in old herbal materials. ITS was employed in a Chinese “cooling” beverage study, in which among 145 sequences, 85.5% were derived from intended species, while the rest were contaminated by fungal or other parasitic species.

Significance: DNA barcoding is a powerful tool for authentication. For herbal materials, there are limitations in the applications due to possessing, storage, and the existence of closely related materials.
All Author(s) ListSHAW Pang Chui, WONG Ka Lok, LO Yat Tung
Name of Conference6th International Barcode of Life Conference
Start Date of Conference18/08/2015
End Date of Conference21/08/2015
Place of ConferenceGuelph, Ontario, Canada
Country/Region of ConferenceCanada
Proceedings TitleGENOME
Detailed descriptionorganized by International Barcode of Life
Volume Number58
Issue Number5
Pages278 - 278
LanguagesEnglish-United Kingdom

Last updated on 2019-15-03 at 17:40