Cynara Scolymus clustering in plant food supplements by high resolution melting analysis Conference Paper uri icon


  • Plant food supplements (PFS) have been regarded with special interest since they are concentrated sources of nutrients or other substances with a nutritional or physiological effect, contributing to a better homeostatic balance. Weight-loss PFS, one of the most consumed PFS, may include Cynara scolymus (artichoke) as an ingredient due to its antioxidant, diuretic, choleretic and hepatoprotective properties [1]. Considered as foods under the EU Directive 2002/46/EC, the PFS are not usually subjected to any safety assessment prior to their commercialisation. This can lead to adulteration issues, such as accidental swap of plants or deliberate substitution of higher cost botanicals by other similar, but cheaper species. Thus, to ensure consumer’s safety, the development of analytical methods for the correct identification of different plant species in PFS has become essential. Until now, DNA-based methods have been reported as highly appropriate tools for plant authentication [2]. The aim of this study was to discriminate C. scolymus from other Cynara spp. using real-time polymerase chain reaction (PCR) coupled to high resolution melting (HRM) analysis. For this purpose, different Cynara species (C. scolymus, C. syriaca, C. cardunculus and C. humilis) were obtained from Portuguese and French Germplasm Banks. A total of 8 PFS tablets for weight-loss containing artichoke were acquired at local herbal stores. DNA from plant material and PFS was extracted using the commercial NucleoSpin Plant II kit. Former to DNA extraction, PFS were pre-treated with a phosphate buffer 1M (pH8, 15% ethanol) to enhance the purity and quality of the extracts. The specificity and sensitivity of the designed primers targeting C. scolymus were assayed by qualitative PCR and real-time PCR with HRM analysis. The application of the specific PCR assay was successful in the detection of Cynara spp. in some of the PFS samples. The results of real-time PCR with HRM analysis showed that different Cynara spp. were included in three distinct clusters with a level of confidence above 99.4%, thus discriminating artichoke from other Cynara species. The proposed HRM analysis allowed confirming the unequivocal presence of C. scolymus in the tested PFS with high level of confidence (>98.8%). To our knowledge, this is the first successful attempt for the rapid discrimination of C. scolymus in PFS.
  • This work was supported by European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project EXPL/DTPSAP/1438/2013 and PEst-C/EQB/LA0006/2013

publication date

  • January 1, 2015