Ommochrome

Chemical structure of xanthommatin, a common ommochrome

Ommochrome (or filtering pigment) refers to several biological pigments that occur in the eyes of crustaceans and insects. The eye color is determined by the ommochromes. Ommochromes are also found in the chromatophores of cephalopods, and in spiders.[1]

Ommochromes are metabolites of tryptophan, via kynurenine and 3-hydroxykynurenine. They are responsible for a wide variety of colors, ranging from yellow over red and brown to black. Lighter colors tend to be generated by ommatins, while mixtures of ommatin and ommins are responsible for darker colors.[1][2]

In spiders, ommochromes are usually deposited as pigment granules within the cells of the hypodermis, immediately beneath the cuticle.[1]

A study on various insects showed that ommochromes in their eyes have high antioxidant activity. The ommochromes were found to have the ability to suppress the Maillard reaction.[3]

Anti-radical capacity

Due to the chemical properties exhibited in the chromophoric groups of ommochromes, these substances have been proven to be satisfactory in functioning as free radicals.[4] In testing the anti-radical capacity of ommochromes, their electron transfer and hydrogen transfer mechanisms were examined, and it was shown that ommochromes posses the ability to prevent oxidative stress by scavenging free radicals. Results regarding this study were quantified using a full-electron donor acceptor map (FEDAM) which allowed for optimal discretion in evaluating anti-radical capacity. [5]

See also

References

  1. ^ a b c Oxford, G. S.; Gillespie, R. G. (1998). "Evolution and Ecology of Spider Coloration". Annual Review of Entomology. 43: 619–643. doi:10.1146/annurev.ento.43.1.619. PMID 15012400. S2CID 6963733.
  2. ^ Casas, J. R. M.; Casas, M. (2009). "The multiple disguises of spiders: Web colour and decorations, body colour and movement". Philosophical Transactions of the Royal Society B: Biological Sciences. 364 (1516): 471–480. doi:10.1098/rstb.2008.0212. PMC 2674075. PMID 18990672.
  3. ^ Dontsov, A. E.; Yakovleva, M. A.; Ostrovsky, M. A. (2021). "Ommochromes of Insect Compound Eyes: Antiglycation Action". Neuroscience and Behavioral Physiology. 51 (6): 837–841. doi:10.1007/s11055-021-01141-y. ISSN 0097-0549. S2CID 254862128.
  4. ^ Figon, Florent; Casas, Jérôme (2018). "Ommochromes in invertebrates: biochemistry and cell biology". Biological Reviews. 94 (1): 156–183. doi:10.1111/brv.12441. ISSN 1464-7931.
  5. ^ Romero, Yanet; Martínez, Ana (2015). "Antiradical capacity of ommochromes". Journal of Molecular Modeling. 21 (8). doi:10.1007/s00894-015-2773-3. ISSN 1610-2940.