title: Decomposition of microcystin-LR, microcystin-RR, and microcystin-YR in water samples submitted to in vitro dissolution tests.
abstract: The presence of cyanobacterial toxins (microcystins) in waters and food increases the risk of toxicity to animal and human health. These toxins can degrade in the human gastrointestinal tract before they are absorbed. To evaluate this possible degradation, water samples spiked with known concentrations of microcystins MC-LR, MC-RR, and MC-YR, which are the toxins most commonly produced by such toxic cyanobacteria as Microcystis aeruginosa, Oscillatoria spp., and Nostoc spp., were submitted to a dissolution test that used gastric and intestinal fluids according to U.S. Pharmacopeia conditions. HPLC with UV detection was used to determine the toxins before and after treatments. This study revealed enzymatic alterations in gastric conditions for all the toxins assayed. MC-RR was the toxin most affected: its range of inactivation was 49-64%. The percentage of degradation for MC-YR and MC-LR was around 30%. However, none was degraded by intestinal digestion.
authors.affiliation: Nutrition, Food Chemistry, and Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Moreno
authors.forename: Judith
authors.initials: J
authors.lastname: Maraver
authors.forename: Esther C
authors.initials: EC
authors.lastname: Aguete
authors.forename: Manel
authors.initials: M
authors.lastname: Leao
authors.forename: Ana
authors.initials: A
authors.lastname: Gago-Martínez
authors.forename: Ana M
authors.initials: AM
authors.lastname: Cameán
mesh_terms: D001427:Bacterial Toxins / Q000737:chemistry; D001826:Body Fluids / Q000378:metabolism; D000458:Cyanobacteria; D004064:Digestive System / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000378:metabolism*; D014867:Water / Q000737:chemistry*
chemical_list: D001427:Bacterial Toxins; D004798:Enzymes; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D014867:Water; C065685:microcystin YR; C063855:microcystin RR; C057862:cyanoginosin LR