Identification of smallanthus sonchifolius in herbal tea mixtures by PCR and DART/TOF-MS methods

The identification of yacon, a medicinal plant, in tea mixtures by rapid Polymerase Chain Reaction (PCR) and the Direct Analysis in Real Time coupled with Time-of-Flight Mass Spectrometry (DART/TOF-MS) method were evaluated. Three tea products and a pure yacon tea were analysed using the molecular method PCR, concretely the intraspecific variation of the internal transcribed spacer (ITS) regions of rDNA and the DART method coupled with TOF-MS. The results show the reliability of PCR and restriction cleavage of the ITS as a combined approach to confirm the presence of yacon in herbal tea mixtures. Three fragments of approximately 700, 408, and 235 bp in length are present when yacon is a part of the herbal tea mixture. The Principal Component Analysis (PCA) based on the fingerprints of the complete Total Ion Current (TIC) mass spectra shows sufficient separation of herbal teas with and without yacon leaves. The reported methods are technically rapid and can be used as an effective tool for the purposes of yacon identification or authentication.