Toxicity and risk of plant-produced alkaloids to Daphnia magna

Abstract

Background Many plants contain phytotoxic alkaloids to deter herbivorous pests and grazing animals. Alkaloids include quinolizidine and indole alkaloids found in the lupin (Lupinus spp.), an ornamental flower and emerging protein crop, as well as pyrrolizidine alkaloids in the ragwort (Senecio jacobaea), an invasive, weed-like flower. When lupins and ragworts are present in large densities in fields, there is a concern that alkaloids may leach into freshwater environments in amounts that may affect non-target organisms, such as Daphnia magna. This study aimed to investigate (i) the acute toxicity of alkaloids (gramine, heliotrine, lupanine, lupinine, monocrotaline, monocrotaline N-oxide, senecionine and sparteine) in D. magna, (ii) the contribution of these individual alkaloids to lupin plant extract toxicity, (iii) the longer term reproductive effects of a representative alkaloid, sparteine, and conclude with (iv) a tentative risk assessment for the sum of alkaloids measured in soil and surface waters. Results The alkaloids exhibited toxicity, with 48 h EC50 values in the range of 5.6 to > 100 mg/L. The 48 h EC50 of the Lupinus angustifolius plant extract was 1.38 mg/L, which was far more toxic than the simulated extract where lethality was < 10% at 10 mg/L after 48 h. Hence, non-measured compounds may have contributed to the joint toxicity. Daphnid mothers exposed to > 2.5 mg/L sparteine produced significantly fewer and smaller offspring during the 21-day exposure, making chronic effects occur at concentrations approximately 10-fold lower than the 48 h EC50 for sparteine. The risk assessment of cumulated alkaloids measured in drain, running and pond waters showed a potential risk, particularly for stagnant pond water, where concentrations were severalfold higher than in the drain and running waters. Conclusions The results highlight that natural toxins may contribute to poor chemical quality of natural waters, and that natural toxins from upcoming crops or invasive weeds should be considered in aquatic risk assessments.

The Beauty is a beast: Does leachate from the invasive terrestrial plant Impatiens glandulifera affect aquatic food webs?

“…If donor plants grow in riparian areas, allelochemicals may cross ecosystem boundaries (Jackrel & Wootton, 2015 ) and leach into the adjacent water bodies, especially during precipitation, which was shown for allelochemicals from bracken (Skrbic et al, 2021 ). Ecotoxicological studies in the laboratory, performed with the extracted allelochemical juglone and other natural toxins, revealed negative effects of these compounds on water dwelling organisms, such as an increased mortality in zoo‐ and phytoplankton (Griffiths et al, 2021 ; Westfall et al, 1961 ; Wright et al, 2007 ). Based on these findings, invasive terrestrial plants, that form monospecific stands in riparian areas may not only affect terrestrial native plant species they may additionally affect the neighboring aquatic ecosystems.…”

“…Based on these findings, invasive terrestrial plants, that form monospecific stands in riparian areas may not only affect terrestrial native plant species they may additionally affect the neighboring aquatic ecosystems. Griffith et al ( 2021 ) could show that plant produced phytotoxic alkaloids, e.g., from the lupin ( Lupinus spp .) or the ragwort ( Senecio jacobaea ), elicit effects on life history and morphological parameters in Daphnia magna .…”

Natural toxins: environmental contaminants calling for attention

“…The fact that some phytotoxins are produced in high amounts, can be stable for months, mobile, and are found in soil pore water, river waters and drinking water resources asks for effect studies and (eco-)toxicological risk assessment. Griffiths et al [61] contribute to the hitherto still very limited data and report EC 50 values of alkaloids lupin and ragwort on Daphnia magna. According to them, there is a potential risk for aquatic organisms in stagnant pond water in vicinity of corresponding vegetation.…”

Enhancement of Polyphenols Recovery from Rosa canina, Calendula officinalis and Castanea sativa Using Pulsed Electric Field

“…Herbal products pose a number of risks (e.g., toxins, pesticides, heavy metals, alkaloids, saponins, etc.) [4][5][6][7], but other functional components having useful actions (i.e., antioxidant activity) show a great potential for illness prevention and treatment, as well as human health promotion [8]. The presence of plant toxins, their bioavailability from the matrix, and interactions with other inherent plant constituents, as well as the potential health benefits of foods (antioxidants and other natural protective agents), should be considered [5].…”