Toxin content and cytotoxicity of algal dietary supplements

Abstract

Blue-green algae (Spirulina sp., Aphanizomenon flos-aquae) and Chlorella sp. are commercially distributed as organic algae dietary supplements. Cyanobacterial dietary products in particular have raised serious concerns, as they appeared to be contaminated with toxins e.g. microcystins (MCs) and consumers repeatedly reported adverse health effects following consumption of these products. The aim of this study was to determine the toxin contamination and the in vitro cytotoxicity of algae dietary supplement products marketed in Germany. In thirteen products consisting of Aph. flos-aquae, Spirulina and Chlorella or mixtures thereof, MCs, nodularins, saxitoxins, anatoxin-a and cylindrospermopsin were analyzed. Five products tested in an earlier market study were re-analyzed for comparison. Product samples were extracted and analyzed for cytotoxicity in A549 cells as well as for toxin levels by (1) phosphatase inhibition assay (PPIA), (2) Adda-ELISA and (3) LC-MS/MS. In addition, all samples were analyzed by PCR for the presence of the mcyE gene, a part of the microcystin and nodularin synthetase gene cluster. Only Aph. flos-aquae products were tested positive for MCs as well as the presence of mcyE. The contamination levels of the MC-positive samples were ≤ 1 μg MC-LR equivalents g(-1) dw. None of the other toxins were found in any of the products. However, extracts from all products were cytotoxic. In light of the findings, the distribution and commercial sale of Aph. flos-aquae products, whether pure or mixed formulations, for human consumption appear highly questionable.

A review of reproductive toxicity of microcystins

“…There is also evidence that MCs may be transmitted to cultivated plants from contaminated irrigation water [140]. Another potential source of human exposure, that should not be neglected, is through dietary supplements sold as blue green algae supplements (BGAS) [141]. However, no data are available that describe the reproductive toxicity of MCs to humans.…”

Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007

“…Potential exposure routes to cyanotoxins include contact, ingestion or inhalation during recreational activities, contaminated drinking water, crops irrigated by contaminated water, and consumption of fish, shellfish, and algal supplements (Chorus and Bartram, 1999;Corbel et al, 2013;Heussner et al, 2012). Cyanobacterial harmful algal blooms (cyanoHABs) have been implicated in human and animal illness and death in over 50 countries and at least 41 U.S. States Backer et al, 2015).…”

Monitoring of essential and toxic elements in multi-ingredient food supplements produced in European Union

“…For example, some microalgae-based products were found to cause significant side effects, exert cytotoxic effects in human cells, and were contaminated with significant levels of lead, aluminium (Rzymski et al 2015a or cyanotoxins (Heussner et al 2012) while bodybuilding FS targeted at sportsman contained prohibited stimulant compounds (Geyer et al 2008) or anabolic androgenic steroids (Abbate et al 2015). Moreover, as found for selenium FS distributed in Poland, the declared nutritional values often differed significantly from actual content .…”