Carnosine (beta-alanyl-L-histidine) is found exclusively in animal tissues. It is a dipeptide of the amino acids beta-alanine and histidine. Carnosine has the potential to suppress many of the biochemical changes (e. g. , protein oxidation, glycation, AGE formation, and cross-linking) that accompany aging and associated pathologies. It is highly concentrated in muscle and brain tissues. Some autistics patients take it as a dietary supplement, and attribute an improvement in their condition to it. Supplemental carnosine may increase corticosterone levels. This may explain the "hyperactivity" seen in autistic subjects at higher doses. Carnosine also exhibits some antioxidant effects. The antioxidant mechanism of carnosine is attributed to its chelating effect against metal ions, superoxide dismutase (SOD)-like activity, ROS and free radicals scavenging ability.
The dipeptide carnosine has been observed to exert antiaging activity at cellular and whole animal levels. This review discusses the possible mechanisms by which carnosine may exert antiaging action and considers whether the dipeptide could be beneficial to humans. Carnosine's possible biological activities include scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS), chelator of zinc and copper ions, and antiglycating and anticross-linking activities. Carnosine's ability to react with deleterious aldehydes such as malondialdehyde, methylglyoxal, hydroxynonenal, and acetaldehyde may also contribute to its protective functions. Physiologically carnosine may help to suppress some secondary complications of diabetes, and the deleterious consequences of ischemic-reperfusion injury, most likely due to antioxidation and carbonyl-scavenging functions. Other, and much more speculative, possible functions of carnosine considered include transglutaminase inhibition, stimulation of proteolysis mediated via effects on proteasome activity or induction of protease and stress-protein gene expression, upregulation of corticosteroid synthesis, stimulation of protein repair, and effects on ADP-ribose metabolism associated with sirtuin and poly-ADP-ribose polymerase (PARP) activities. Evidence for carnosine's possible protective action against secondary diabetic complications, neurodegeneration, cancer, and other age-related pathologies is briefly discussed.
Hipkiss, A. R. (2009). Carnosine and its possible roles in nutrition and health. Advances in food and nutrition research, 57, 87-154.