Lars Holm Rasmussen

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The distribution of ptaquiloside (PTA) was studied in four Danish bracken populations in order to evaluate the transfer of PTA from ferns to soil. Populations showed statistically significant differences in PTA contents of fronds and rhizomes despite large in-site variations. The highest concentrations were encountered in fronds with concentrations ranging(More)
Secondary metabolites from bracken fern (Pteridium aquilinum (L.) Kuhn) are suspected of causing cancer in humans. The main carcinogen is the highly water-soluble norsesquiterpene glucoside ptaquiloside, which may be ingested by humans through food, e.g. via contaminated water, meat or milk. It has been postulated that carcinogens could also be ingested(More)
Bracken ferns are some of the most widespread ferns in the World causing immense problems for land managers, foresters and rangers. Bracken is suspected of causing cancer in Humans due to its content of the carcinogen ptaquiloside. Ingestion of bracken, or food and drinking water contaminated with ptaquiloside may be the cause. The aim of this study was to(More)
Bracken (Pteridium aquilinum (L.) Kuhn) is a common fern found on all continents except Antarctica. It is under suspicion of causing cancer among people who utilizes it as food. The main carcinogenic compound is thought to be the water-soluble compound ptaquiloside. Ptaquiloside-uptake may occur not only through food, but also via drinking water as(More)
Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glucoside produced by Bracken in amounts up to at least 500 mg m(-2). The toxin is transferred from Bracken to the underlying soil from where it may leach to surface and groundwater's impairing the quality of drinking water. The objectives of the present study were to characterize the solubility,(More)
The carcinogenic and toxic ptaquiloside (PTA) is a major secondary metabolite in Bracken fern (Pteridium aquilinum (L.) Kuhn) and was hypothesized to influence microbial communities in soil below Bracken stands. Soil and Bracken tissue were sampled at field sites in Denmark (DK) and New Zealand (NZ). PTA contents of 2.1 +/- 0.5 mg g(-1) and 37.0 +/- 8.7 mg(More)
Ptaquiloside (PTA) is a well-known toxin produced by the bracken fern (Pteridium aquilinum (L.) Kuhn). It is proposed that PTA from bracken stands can leach through soil and sediments into drinking-water reservoirs, thus representing a concern for human health. To predict the persistence of the toxin, a full understanding of the PTA degradation in aqueous(More)
Cyanogenic glycosides are common plant toxins. Toxic hydrogen cyanide originating from cyanogenic glycosides may affect soil processes and water quality. In this study, hydrolysis, degradation and sorption of dhurrin (4-hydroxymandelonitrile-beta-d-glucoside) produced by sorghum has been studied in order to assess its fate in soil. The log K(ow) of dhurrin(More)
Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glycoside produced in bracken (Pteridium aquilinum (L.) Kuhn), a widespread, aggressive weed. Transfer of PTA to soil and soil solution eventually may contaminate groundwater and surface water. Degradation rates of PTA were quantified in soil and soil solutions in sandy and clayey soils subjected to high(More)
Ptaquiloside (PTA) is a toxin from bracken fern (Pteridium sp.) with genotoxic effects. Hydrolysis of PTA leads to the non-toxic and aromatised indanone, pterosin B (PTB). Here we present a sensitive, fast, simple and direct method, using SPE cartridges to clean and pre-concentrate PTA and PTB in plasma, urine and milk followed by LC-MS quantification. The(More)