3-Hydroxykynurenine as a radical scavenger in the blowfly, Aldrichina grahami

3-Hydroxykynurenine (3-HOK) accumulated in may tissues of A. grahami, especially in the Malpighian tubules. The compound was present in the insect during its whole life cycle. Its content in the insect seemed to be more than that needed for the synthesis of ommochrome, and was also 5–10-fold of the concentration of other reductants. It can protect the fat body cells of A. grahami from peroxidation and also suppress the decrease of respiration of the cells due to injury by t-butylhydroperoxide (t-BuOOH). The effects of the compound are superior to those of reduced glutathione and uric acid, and approach those of ascorbic acid. The protection of the respiration against injury from t-BuOOH means that 3-HOK effectively scavenged radicals and the more 3-HOK the tissue contained, the less the fat body was injured by t-BuOOH.