Interaction of microcystin-LR with SuperChar: water decontamination and therapy.

Activated charcoal (SuperChar) has been recommended for therapeutic use against poisoning by several toxic agents, but it has not been tested against microcystin-LR toxicosis. Microcystin-LR, a cyclic heptapeptide isolated from fresh water blue-green algae, has been shown to be a potent hepatotoxin in animals and in man. Studies were performed to determine the degree of in vitro adsorption of microcystin-LR to SuperChar and to assess the efficacy of SuperChar as a therapeutic agent against microcystin-LR in vivo. Scatchard analysis of the in vitro data showed that microcystin-LR bound to SuperChar with a maximum binding capacity of 0.692 mM toxin/g SuperChar with a dissociation constant of 0.016 mM. The adsorption characteristics of microcystin-LR by SuperChar was applied successfully to the decontamination of water samples spiked with microcystin-LR. While an oral (po) dose of toxin mixed with SuperChar (0.31-0.36 g/kg) modulated the toxicity, an oral pretreatment with SuperChar did not prevent lethality induced by an oral or intraperitoneal (ip) dose of microcystin-LR in mice.