Neurotoxic activity of polar substances extracted from the red seaweed Galaxaura marginata was investigated in pharmacological assays, using seaweed collected at São Sebastião channel (45º25' W; 26º49' S) in the northern coast of the State of São Paulo, Brazil. High concentration of the polar fraction (PF) and PF filtered through a membrane (1000 Da) intraperitoneally (IP) injected in mice were lethal, inducing ataxia, disorientation, and severe muscle atonia prior to death. The same symptoms preceding death were described in mice and rat tested with neuroexcitatory amino acids (NEA), suggesting that some PF components cross the blood-brain barrier, the same as NEA. However, the HPLC and mass spectrometric analysis did not show the presence of the known neuroexcitatory amino acids, kainic acid, domoic acid and NMDA. We conclude that G. marginata possess substances with neurotoxic and lethal activities.
Galaxaura marginata; neurotoxic; neuroexcitatory; seaweed
