title: The red seaweed Plocamium brasiliense shows anti-snake venom toxic effects.
abstract: BACKGROUND
  Snakebite is considered a neglected tropical disease by the World Health Organization. In Brazil, about 70% of the envenomation cases are caused by Bothrops snakes. Its venom may provoke hemorrhage, pain, necrosis, hemolysis, renal or cardiac failure and even death in victims. Since commercial antivenom does not efficiently neutralize the local toxic effects of venoms, natural products have been tested in order to provide alternative or complementary treatment to serum therapy. Therefore, the present study aimed to evaluate the ability of the seaweed Plocamium brasiliense and its active derivatives to neutralize hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic activities of B. jararaca venom.
  
  
  METHODS
  Specimens of P. brasiliense were collected in Rio de Janeiro state, Brazil, dried and submitted to oil extraction using four solvents of increasing polarities, n-hexane (HEX), dichloromethane (DCM), ethyl acetate (ETA) and hydroalcoholic solution (HYD). The solvents were evaporated, yielding HEX, DCM, ETA and HYD extracts. Further, all extracts were dissolved in dimethylsulfoxide. In addition, two monoterpenes (8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene and 1,8-dibromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene) and a cholesterol fraction were isolated from the extract of P. brasiliense prepared in hexane. Algal samples were incubated for 30 minutes with B. jararaca venom, and then tested for lethality; hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic effects.
  
  
  RESULTS
  Most of the algal extracts inhibited the toxic effects with different potencies. The DCM extract was the most effective, since it inhibited all types of toxic activity. On the other hand, the HYD extract failed to inhibit any effect. Moreover, the isolated products inhibited proteolysis and protected mice from hemorrhage in 30% of the cases, whereas 8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene inhibited 100% and 20% of the hemorrhagic and proteolytic activities, respectively. None of the algal products were toxic to mice.
  
  
  CONCLUSIONS
  Seaweeds may be a promising source of inhibitors against toxic effects caused by B. jararaca envenomation, which may contribute to antivenom treatment.
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Biology, Federal Fluminense University (UFF), Niterói, Rio de Janeiro State Brazil.
authors.forename: Geisiane Alves
authors.initials: GA
authors.lastname: da Silva
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Biology, Federal Fluminense University (UFF), Niterói, Rio de Janeiro State Brazil.
authors.forename: Thaisa Francielle Souza
authors.initials: TF
authors.lastname: Domingos
authors.affiliation: Department of Organic Chemistry, Institute of Chemistry, Federal Fluminense University (UFF), Niterói, Rio de Janeiro State Brazil.
authors.forename: Rainiomar Raimundo
authors.initials: RR
authors.lastname: Fonseca
authors.affiliation: Laboratory of Biochemistry of Proteins from Animal Venoms, Research and Development Center, Ezequiel Dias Foundation, Belo Horizonte, Minas Gerais State Brazil.
authors.forename: Eladio Flores
authors.initials: EF
authors.lastname: Sanchez
authors.affiliation: Department of Marine Biology, Institute of Biology, Federal Fluminense University (UFF), Niterói, Rio de Janeiro State Brazil.
authors.forename: Valéria Laneuville
authors.initials: VL
authors.lastname: Teixeira
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Biology, Federal Fluminense University (UFF), Niterói, Rio de Janeiro State Brazil.
authors.forename: André Lopes
authors.initials: AL
authors.lastname: Fuly
keywords: Antivenom; Bioprospecting; Bothrops jararaca; Plocamium brasiliense; Seaweed; Snake venom