Isolation of brominated quinones showing chemiluminescence activity from luminous acorn worm, Ptychodera flava.

Luminous acorn worm, Ptychodera flava emits green light by stimulating with diluted hydrogen peroxide. We have recently reported isolation and structure determination of 2,3,5,6-tetrabromohydroquinone as a luminous substance and riboflavin as a possible light emitter. There are three other luminous substances in the extracts from P. flava, so here we report the isolation and structure determination of other luminous substances as 2,3,5-tribromohydroquinone, tetrabromo-1,4-benzoquinone, and 2,3,5-tribromo-6-(2,3,5-tribromo-4-hydroxy-phenoxy)-benzene-1,4-diol. Besides, this is the first report of isolation of tetrabromo-1,4-benzoquinone from acorn worm. Structure-activity relationship of chemiluminescence activity of halogenated quinone derivatives reveals that a highly halogen substitution and 1,4-quinone skeleton are important for high chemiluminescence activity.