title: Hybrid analysis (barcode-high resolution melting) for authentication of Thai herbal products, Andrographis paniculata (Burm.f.) Wall.ex Nees.
abstract: BACKGROUND
  Andrographis paniculata Nees is a medicinal plant with multiple pharmacological properties. It has been used over many centuries as a household remedy. A. paniculata products sold on the markets are in processed forms so it is difficult to authenticate. Therefore buying the herbal products poses a high-risk of acquiring counterfeited, substituted and/or adulterated products. Due to these issues, a reliable method to authenticate products is needed.
  
  
  METHODS
  High resolution melting analysis coupled with DNA barcoding (Bar-HRM) was applied to detect adulteration in commercial herbal products. The rbcL barcode was selected to use in primers design for HRM analysis to produce standard melting profile of A. paniculata species. DNA of the tested commercial products was isolated and their melting profiles were then generated and compared with the standard A. paniculata.
  
  
  RESULTS
  The melting profiles of the rbcL amplicons of the three closely related herbal species (A. paniculata, Acanthus ebracteatus and Rhinacanthus nasutus) are clearly separated so that they can be distinguished by the developed method. The method was then used to authenticate commercial herbal products. HRM curves of all 10 samples tested are similar to A. paniculata which indicated that all tested products were contained the correct species as labeled.
  
  
  CONCLUSIONS
  The method described in this study has been proved to be useful in aiding identification and/or authenticating A. paniculata. This Bar-HRM analysis has allowed us easily to determine the A. paniculata species in herbal products on the markets even they are in processed forms.
  
  
  CONCLUSIONS
  We propose the use of DNA barcoding combined with High Resolution Melting analysis for authenticating of Andrographis paniculata products.The developed method can be used regardless of the type of the DNA template (fresh or dried tissue, leaf, and stem).rbcL region was chosen for the analysis and work well with our samplesWe can easily determine the A. paniculata species in herbal products tested. Abbreviations used: bp: Base pair, Tm: Melting temperature.
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Maslin
authors.initials: M
authors.lastname: Osathanunkul
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; School of Agriculture and Natural Resources, University of Phayao, Phayao, 56000, Thailand.
authors.forename: Chatmongkon
authors.initials: C
authors.lastname: Suwannapoom
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Nuttaluck
authors.initials: N
authors.lastname: Khamyong
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Danupol
authors.initials: D
authors.lastname: Pintakum
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Santisuk Na
authors.initials: SN
authors.lastname: Lamphun
authors.affiliation: Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.
authors.forename: Kanokporn
authors.initials: K
authors.lastname: Triwitayakorn
authors.affiliation: Department of Computer Science, Faculty of Science, Maejo University, Chiang Mai, 50290, Thailand.
authors.forename: Kitisak
authors.initials: K
authors.lastname: Osathanunkul
authors.affiliation: Institute of Applied Biosciences, CERTH, 6 km Charilaou-Thermis Road, Thermi, Thessaloniki, 57001, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Madesis
keywords: Andrographis paniculata; DNA barcoding; authentication; herbal product; high resolution melting; species identification