A Systematic Literature Review for Evidence of Aphanizomenon flos-aquae Toxigenicity in Recreational Waters and Toxicity of Dietary Supplements: 2000–2017

Abstract

Previous studies of recreational waters and blue-green algae supplements (BGAS) demonstrated co-occurrence of Aphanizomenon flos-aquae (AFA) and cyanotoxins, presenting exposure risk. The authors conducted a systematic literature review using a GRADE PRISMA-p 27-item checklist to assess the evidence for toxigenicity of AFA in both fresh waters and BGAS. Studies have shown AFA can produce significant levels of cylindrospermopsin and saxitoxin in fresh waters. Toxicity studies evaluating AFA-based BGAS found some products carried the mcyE gene and tested positive for microcystins at levels ≤ 1 μg microcystin (MC)-LR equivalents/g dry weight. Further analysis discovered BGAS samples had cyanotoxins levels exceeding tolerable daily intake values. There is evidence that Aphanizomenon spp. are toxin producers and AFA has toxigenic genes such as mcyE that could lead to the production of MC under the right environmental conditions. Regardless of this ability, AFA commonly co-occur with known MC producers, which may contaminate BGAS. Toxin production by cyanobacteria is a health concern for both recreational water users and BGAS consumers. Recommendations include: limit harvesting of AFA to months when toxicity is lowest, include AFA in cell counts during visible blooms, and properly identify cyanobacteria species using 16S rRNA methods when toxicity levels are higher than advisory levels.

Herbal/Plant Remedies and Supplements Used by Hispanics/Latinxs for Diabetes: Source of Functional Foods?

“…43 A recent systematic literature review assessing the safety of AFA in dietary supplements revealed that many AFA supplements are contaminated with cyanotoxins, which are harmful toxins to the liver, nervous system, and skin in humans and advised caution for using AFA supplements. 44…”

Recent advances in the integrated biorefinery concept for the valorization of algal biomass through sustainable routes

“…Microalgae own antiviral, antibacterial, anti‐HIV, anticancer, and numerous neurological actions 112,192–195 . Dinoflagellates and BGA produce extremely effective toxins such as Microcystins 193 . Toxins produced by BGA, Prymnesium parvum sp., and Ochromonas sp.…”

Toxic compounds produced by cyanobacteria belonging to several species of the order Nostocales: A review

“…The adverse effects of a strain of Aphanizomenon issastchenkoi (LMECYA31), producing saxitoxins, on the survival and somatic growth of Daphnia magna were found (Nogueira et al, 2004). STX is also capable of entering the human body via a cut or other open wound, and the predicted human LD 50 based on previous mice studies, via this route of exposure, has been estimated to be 50 μg/kg body weight (Lyon-Colbert et al, 2018). Currently, the acute RfD (acute reference dose), used in place of the noobserved-adverse-effect level, is 0.5 μg STX equivalent/kg-day (Chain, 2009).…”