Abstract
Algae dietary supplements are marketed worldwide as natural health products. Although their proprieties have been claimed as beneficial to improve overall health, there have been several previous reports of contamination by cyanotoxins. These products generally contain non-toxic cyanobacteria, but the methods of cultivation in natural waters without appropriate quality controls allow contamination by toxin producer species present in the natural environment. In this study, we investigated the presence of total microcystins, seven individual microcystins (RR, YR, LR, LA, LY, LW, LF), anatoxin-a, dihydroanatoxin-a, epoxyanatoxin-a, cylindrospermopsin, saxitoxin, and β-methylamino-l-alanine in 18 different commercially available products containing Spirulina or Aphanizomenon flos-aquae. Total microcystins analysis was accomplished using a Lemieux oxidation and a chemical derivatization using dansyl chloride was needed for the simultaneous analysis of cylindrospermopsin, saxitoxin, and β-methylamino-l-alanine. Moreover, the use of laser diode thermal desorption (LDTD) and ultra-high performance liquid chromatography (UHPLC) both coupled to high resolution mass spectrometry (HRMS) enabled high performance detection and quantitation. Out of the 18 products analyzed, 8 contained some cyanotoxins at levels exceeding the tolerable daily intake values. The presence of cyanotoxins in these algal dietary supplements reinforces the need for a better quality control as well as consumer’s awareness on the potential risks associated with the consumption of these supplements.
Highlights
Cyanobacteria (CB), formally called blue-green algae, are omnipresent in natural water sources and cause increased concern for public health [1]
We aim to analyze different brands of CB dietary supplements to screen for the presence of different cyanotoxins: microcystins (MCs), anatoxin-a (ANA-a), cylindrospermopsin (CYN), saxitoxin (STX), and β-methylamino-L-alanine (BMAA)
Different analytical approaches have been used to determine the presence of several cyanotoxins in Spirulina and A. flos-aquae dietary supplements available worldwide in stores or via the Internet [11,12,13,17,34,35,36]
Summary
Cyanobacteria (CB), formally called blue-green algae, are omnipresent in natural water sources and cause increased concern for public health [1]. They are mostly innocuous, a significant proportion of cyanobacterial species are harmful due to toxin production [2]. The production of massive cyanobacterial blooms can be caused by eutrophic conditions in the presence of heat, light, shallow waters, and nutrients [1,3]. Intense agriculture activities, and more recently, climate changes have been the principal triggers of massive cyanobacterial blooms [4,5]. The production of cyanobacteria, as well as their cyanotoxins, is almost impossible to predict precisely [6]. The nature of the producing cells and toxins, the localization of proliferation, and the duration of the bloom at a specific location are hard to characterize, which makes their management difficult
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