Decomposition of cyanobacterial microcystins by iron(III) chloride

Microcystins RR and LR, which were mainly detected in Japan, were reacted with iron(III) chloride in 0.1N hydrochloric acid. Fifty percent of microcystins RR and LR were immediately decomposed at less than ten minutes, and the decomposition was not dependent on pH (2.0-8.0). The decomposed product was purified by a Sep-Pak C18 cartridge, and chromatographed by a silica gel thin layer. As a result, about eight spots were observed in the decomposed product line, three of which were ninhydrin-negative; the others positive. One of these ninhydrin-negative spots was determined (2S, 3S, 8S)-3-amino-2, 6, 8-trimehyl-10-phenyldeca-4E, 6E-dienoic acid by GC-MS analysis. In addition, the product obtained from the decomposed microcystin LR with iron(III) chloride did not have an acute toxicity.