title: Environmental neurotoxins β-N-methylamino-l-alanine (BMAA) and mercury in shark cartilage dietary supplements.
abstract: Shark cartilage products are marketed as dietary supplements with claimed health benefits for animal and human use. Shark fin and cartilage products sold as extracts, dry powders and in capsules are marketed based on traditional Chinese medicine claims that it nourishes the blood, enhances appetite, and energizes multiple internal organs. Shark cartilage contains a mixture of chondroitin and glucosamine, a popular nutritional supplement ingested to improve cartilage function. Sharks are long-lived apex predators, that bioaccumulate environmental marine toxins and methylmercury from dietary exposures. We recently reported detection of the cyanobacterial toxin β-N-methylamino-l-alanine (BMAA) in the fins of seven different species of sharks from South Florida coastal waters. Since BMAA has been linked to degenerative brain diseases, the consumption of shark products may pose a human risk for BMAA exposures. In this report, we tested sixteen commercial shark cartilage supplements for BMAA by high performance liquid chromatography (HPLC-FD) with fluorescence detection and ultra performance liquid chromatography/mass spectrometry/mass spectrometry (UPLC-MS/MS). Total mercury (Hg) levels were measured in the same shark cartilage products by cold vapor atomic fluorescence spectrometry (CVAFS). We report here that BMAA was detected in fifteen out of sixteen products with concentrations ranging from 86 to 265μg/g (dry weight). All of the shark fin products contained low concentrations of Hg. While Hg contamination is a known risk, the results of the present study demonstrate that shark cartilage products also may contain the neurotoxin BMAA. Although the neurotoxic potential of dietary exposure to BMAA is currently unknown, the results demonstrate that shark cartilage products may contain two environmental neurotoxins that have synergistic toxicities.
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA. Electronic address: kmondo@med.miami.edu.
authors.forename: Kiyo
authors.initials: K
authors.lastname: Mondo
authors.affiliation: Department of Chemistry, University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada. Electronic address: williambrocglover@gmail.com.
authors.forename: W
authors.initials: W
authors.lastname: Broc Glover
authors.affiliation: Department of Chemistry, University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada. Electronic address: susan.murch@ubc.ca.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Murch
authors.affiliation: Bioinorganic and Environmental Analytical Facility, Florida International University, 11200 SW 8th St., Miami, FL 33199, USA. Electronic address: liug@fiu.edu.
authors.forename: Guangliang
authors.initials: G
authors.lastname: Liu
authors.affiliation: Bioinorganic and Environmental Analytical Facility, Florida International University, 11200 SW 8th St., Miami, FL 33199, USA. Electronic address: caiy@fiu.edu.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA. Electronic address: d.davis12@med.miami.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Davis
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA. Electronic address: dmash@med.miami.edu.
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Mash
mesh_terms: D000599:Amino Acids, Diamino / Q000032:analysis / Q000633:toxicity*; D001427:Bacterial Toxins / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D000458:Cyanobacteria / Q000737:chemistry; D000087522:Cyanobacteria Toxins; D019587:Dietary Supplements; D004340:Drug Contamination; D004777:Environment; D008387:Marine Toxins / Q000633:toxicity; D008628:Mercury / Q000032:analysis / Q000633:toxicity*; D052998:Microcystins / Q000633:toxicity; D009498:Neurotoxins / Q000032:analysis / Q000633:toxicity*; D053719:Tandem Mass Spectrometry; D014020:Tissue Extracts / Q000737:chemistry / Q000633:toxicity*
chemical_list: D000599:Amino Acids, Diamino; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D009498:Neurotoxins; D014020:Tissue Extracts; C111481:shark cartilage extract; C001824:beta-N-methylamino-L-alanine; D008628:Mercury
keywords: Cyanotoxin; Dietary supplements; Mercury; Shark cartilage; β-N-methylamino-l-alanine