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Screening for Ptaquiloside in Ferns: Using Herbarium Specimens for Qualitative Mapping Purposes
Author(s) -
Rasmussen Lars Holm,
Pedersen Henrik Ærenlund
Publication year - 2017
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.2707
Subject(s) - pteridium aquilinum , bracken , fern , herbarium , frond , chemistry , oleanane , anthraquinone , botany , biology , organic chemistry , medicine , alternative medicine , pathology , triterpene
Ptaquiloside (PTA) is a noxious carcinogen found widespread in Bracken ( Pteridium sp.) but with scattered and unresolved distribution outside the genus . The carcinogen causes Bovine Enzootic Haematuria among cattle all‐over the World and is under suspicion of causing human cancers. Objective To set‐up a methodology for large‐scale qualitative studies on the distribution of PTA in ferns using already available herbarium specimens as source. Methodology PTA and the main degradation product pterosin B (PtB) were quantified in aqueous frond extracts by HPLC‐DAD. PTA was quantified after forced reaction into PtB. Optimal reaction conditions were tested using hydrochloric acid, sulphuric acid, trifluoroacetic acid (TFA), acetic acid and temperature as the experimental variables. A pair‐wise test for PTA degradation in plant‐press were used to explore the effect of this preservation regime. A selection of up to 50 years old Bracken herbarium specimens were tested for PTA and PtB. The methodology was applied on 21 fern species from Denmark. Results An optimised TFA‐based method results in 30.7% higher conversion and a 1:1 reaction between PTA and PtB. Full three‐dimensional resolution of the analyte was obtained. Preservation of fronds in a plant press increase formation of PtB. Hence, the method is only suitable for qualitative studies. Presence of PTA and PtB were found in samples up to 50 years old. Among 21 ferns tested, the compounds were only found in Pteridium aquilinum . Conclusion Herbarium specimens up to 50 years old can be used for explorative risk assessment of ferns using HPLC‐DAD for quantification and identification. Copyright © 2017 John Wiley & Sons, Ltd.