Toxin content and cytotoxicity of algal dietary supplements

• Published in: Toxicology and applied pharmacology 2012-12, Vol.265 (2), p.263-271
• Main Authors: Heussner, A.H., Mazija, L., Fastner, J., Dietrich, D.R.
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Anatoxin-a; Aphanizomenon - chemistry; Aphanizomenon - genetics; Aphanizomenon flos-aquae; Bacterial Toxins - analysis; Bacterial Toxins - toxicity; Bacteriology; BGAS; Biological and medical sciences; Cell Line; Cell Survival - drug effects; CHLORELLA; Chromatography, Liquid; CYANOBACTERIA; Cylindrospermopsin; Dietary Supplements - analysis; Dietary Supplements - toxicity; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; ENZYME IMMUNOASSAY; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; GENES; Germany; Green algae; Humans; IN VITRO; INHIBITION; LIGASES; Medical sciences; Microbiology; Microcystin; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Plant poisons toxicology; POLYMERASE CHAIN REACTION; Protein Phosphatase 1 - antagonists & inhibitors; Protein Phosphatase 1 - metabolism; Saxitoxin; Spirulina; Tandem Mass Spectrometry; TOXICITY; Toxicology; TOXINS
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2012.10.005

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 ≤1μg 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. ► Marketed algae dietary supplements were analyzed for toxins. ► Methods: Phosphatase inhibition assay (PPIA), Adda-ELISA, LC-MS/MS. ► Aph. flos-aquae products all tested positive for microcystins. ► Products tested negative for nodularins, saxitoxins, anatoxin-a, cylindrospermopsin. ► Extracts from all products were cytotoxic.