HRM analysis targeting ITS1 and matK loci as potential DNA mini-barcodes for the authentication of Hypericum perforatum and Hypericum androsaemum in herbal infusions
Hypericum species are among the medicinal plants that are being increasingly used due to their reported
health benefits. Hypericum perforatum (St. John's wort) is well known for its anti-inflammatory, antidepressive
and anti-viral properties, as well as a healing agent. In Portuguese folk medicine, Hypericum
androsaemum (Hiperic~ao do Ger^es) is largely used for its hepatic protective and diuretic properties. This
work aimed at searching the potential use of two DNA mini-barcode candidates (ITS1 and matK) for the
authentication of H. perforatum and H. androsaemum in herbal infusions. The sequencing results from
ITS1 and matK regions were the basis for the development of species-specific PCR and real-time PCR
assays coupled to High Resolution Melting (HRM) analysis, as simple approaches for the reliable
discrimination of both species. The barcode regions were successful in the species-specific PCR identification
of each target. ITS1 region revealed some intra-species variability from sequencing results, which
compromises HRM analysis, while matK showed to be an adequate mini-barcode for the differentiation
of both species by real-time PCR coupled to HRM analysis. The assays were effectively applied to commercial
herbal infusions, enabling the consistent identification of two labels with non-declared Hypericum
species.
This work received financial support from the European Union
(FEDER funds through COMPETE) and National Funds (FCT,
Fundação para a Ciência e Tecnologia) through project EXPL/DTPSAP/
1438/2013 (4SaferPFS e Safety of plant food supplements:
searching for adulterant pharmaceutical drugs and plants) and UID/
QUI/50006/2013. Joana Costa is grateful to FCT grant (SFRH/BPD/
102404/2014) financed by POPH-QREN (subsidised by FSE and
MCTES). The authors are grateful for the supply of voucher seeds by
USDA-ARS Germplasm (Beltsville, MD, USA) and by RBG (Kew,
Ardingly, UK).
