Profiling of Dehydropyrrolizidine Alkaloids and their N -Oxides in Herbarium-Preserved Specimens of Amsinckia Species Using HPLC-esi(+)MS

Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 03/2014; 62(30). DOI: 10.1021/jf500425v
Source: PubMed


Species of the Amsinckia genus (Boraginaceae) are known to produce potentially hepato-, pneumo- and/or geno-toxic dehydropyrrolizidine alkaloids. However, the taxonomic differentiation of Amsinckia species can be very subtle and there seems to be marked differences in toxicity towards grazing livestock. Methanol extracts of mass-limited leaf samples from herbarium specimens (collected from 1899 to 2013) of 10 Amsinckia species and one variety were analyzed using HPLC-esi(+)MS and MS/MS for the presence of potentially toxic dehydropyrrolizidine alkaloids and/or their N-oxides. Dehydropyrrolizidine alkaloids were detected in all specimens examined ranging from about one to 4000 g/g of plant. Usually occurring mainly as their N¬-oxides, the predominant alkaloids were the epimeric lycopsamine and intermedine. Also sometimes observed in higher concentrations were the 3'- and 7-acetyl derivatives of lycopsamine/intermedine and their N-oxides. Within a designated species, an inconsistent profile was often observed that may be due to natural variation, taxonomic misassignment or non-uniform degradation due to plant collection and storage differences.

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    • "In only one of the hay samples a PA-amount of 549 g/kg (sum of PANO and otonecine amines) was detected (Mulder et al., 2009). These comparably high levels are in accordance with other literature reports that PA/PANO are mainly stable in dried forage such as hay or grass (Candrian et al., 1984;Colegate et al., 2014;DEFRA, 2007;Wiedenfeld, 2011). Nonetheless, it should be taken into account a potential for overlooking PA and PANO due to targeting only the commercially available reference standards. "
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    ABSTRACT: Hepatotoxic 1,2-dehydro-pyrrolizidine alkaloids (PA) and their N-oxides (PANO) in feed are a potential threat for animal and human health. However, their risk assessment in preserved animal forage is difficult due to data gaps regarding their occurrence in field samples and contradictory results regarding their behavior during the ensilage process. In this study, 115 samples of grass silage originating from different districts in Bavaria (Germany) were analyzed for their PA and PANO contents. A sensitive LC–ESI-MS/MS method for the detection of 10 PA and 4 PANO was developed including a clean-up of the aqueous acidic extract by cation-exchange cartridges. The mean recoveries were between 70% for seneciphylline-N-oxide and 104% for senecionine-N-oxide. The limits of detection ranged between 0.14 μg senkirkine/kg dry matter (DM) and 1.3 μg retrorsine-N-oxide or monocrotaline-N-oxide/kg DM. Eighteen percent of the samples contained one or more of the analyzed compounds. The highest observed value, calculated as the sum of seneciphylline and senecionine, was 30 μg/kg DM. Other samples contained senecionine-N-oxide, seneciphylline-N-oxide, lycopsamine, intermedine, echimidine, and heliotrine in lower amounts. An accompanying laboratory scale ensilage trial showed a compound-dependent transformation of PANO during the fermentation process while PA-amounts remained stable or even increased. Impacts on safety of ensiled animal feed are discussed with regard to animal health.
    No preview · Article · Jun 2015 · Animal Feed Science and Technology