Anatoxin-a and Its Metabolites in Blue-Green Algae Food Supplements from Canada and Portugal

• Published in: Journal of food protection 2007-03, Vol.70 (3), p.776-779
• Main Authors: Rawn, D.F.K, Niedzwiadek, B, Lau, B.P.Y, Saker, M
• Format: Article
• Language: English
• Subjects: Algae; anatoxins; Animals; Biological and medical sciences; Canada; Chromatography, High Pressure Liquid - methods; Chromatography, Liquid; Consumer Product Safety; Cyanobacteria; Cyanobacteria - metabolism; Cyanobacteria Toxins; dietary supplements; Dietary Supplements - analysis; Dietary Supplements - microbiology; Dietary Supplements - standards; Fluorescence; food contamination; Food Contamination - analysis; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; health foods; hepatotoxins; Humans; metabolites; microcystins; neurotoxins; Portugal; Research and development. New food products, dietetic foods and beverages; Sensitivity and Specificity; Spirulina; Spirulina - metabolism; Tandem Mass Spectrometry - methods; toxic substances; Tropanes - analysis
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-70.3.776

Blue-green algae and spirulina are marketed in health food stores and over the Internet as food supplements in Canada, the United States, and Europe. The reported benefits of consuming these products include improved digestion, strengthening of the immune system, and relief from the symptoms of attention deficit disorder. Some of these products have been found to contain elevated concentrations of microcystins, which are known hepatotoxins. In addition to producing microcystins, Anabaena sp. and Aphanizomenon sp. also produce the potent neurotoxin anatoxin-a. Samples of food supplements containing blue-green algae and spirulina were collected in Portugal and from urban centers across Canada in 2005. Extracts of these supplements were analyzed to determine the presence and concentrations of anatoxin-a and its two main metabolites, dihydroanatoxin-a and epoxyanatoxin-a. Initial analyses were performed using high-performance liquid chromatography (HPLC) with fluorescence detection, and confirmation required the use of LC with tandem mass spectrometry (LC-MS-MS). The HPLC with fluorescence detection indicated no anatoxin-a, but four samples were suspected to contain either dihydroanatoxin-a or epoxyanatoxin-a at 0.1 to 0.2 microgram/g. LC-MS-MS results, however, indicated no trace of either transformation product in any sample analyzed. The detection limits for anatoxin-a, dihydroanatoxin-a, and epoxyanatoxin-a were similar for both fluorescence detection (0.2 to 0.3, 0.4 to 1.4, and 0.2 to 1.5 pg on the column, respectively) and mass spectrometry (0.3 to 1.5, 0.3 to 0.8, and 0.5 to 0.8 pg on the column, respectively). Because of the higher specificity of the LC-MS-MS analysis, all tested food supplement samples were considered free of anatoxin-a and its transformation products.