Linden flower is a wildly used plant material among patients in the treatment of common cold symptoms and mucosa inflammations. The pharmacopoeial monograph refers to three Tilia species as a valid source of a medicinal plant material – Tiliae flos. Those species are T. platyphyllos, T. cordata and T. x vulgaris (T. europea). Up to date there are no reports on differences in the chemical composition of the extracts prepared from flowers of those three species.
The aim of the study was to investigate the differences in a polyphenolic composition of infusions prepared from flowers obtained from three pharmacopoeial species and two non-pharmacopeial species (T. tomentosa and T. americana).
Almost two hundred samples of flowers of Tilia collected between 2013-2016 in different regions of Poland and Europe were investigated. The UHPLC-DAD-MS method using Kinetex XB-C18 column was developed. Chromatograms were recorded at 254, 280 and 350 nm. The MS spectra were analyzed in negative ion mode. Over 40 compounds were detected and characterized comprising flavan-3-ols, flavonoids and phenolic acids. The identification was based on the comparison with available chemical standards and on the literature data. Major compounds from groups of flavan-3-ols and flavonoids were quantified using a validated method with epicatechin and isoquercitrin as reference standards.
It was shown that linarin (acacetin 7-O-rutinoside) is a valid chemotaxonomic marker for T. cordata and T. x vulgaris. Two quercetin O-rhamnohexosides were identified as markers for T. platyphyllos and T. x vulgaris. No differences in the chemical composition was observed as far as flavan-3-ol derivatives are considered. The study for the first time provided simple solution for the differentiation of extracts from three pharmacopoeial Tilia species using a single UPLC-DAD-MS analysis.
Acknowledgements : The project was financially supported by Polish National Science Centre research grant SONATA No. 2015/17/D/NZ7/02641.