Comparative Study of Antioxidant Activity between Carnosine and Its Amino Acid Constituents

A study was conducted to compare and analyze the antioxidant mechanism of carnosine to its constituent amino acids (β-alanine and L-histidine) and to imidazole. Concentrations ranging from 5 to 100 mM of carnosine, β-alanine, L-histidine and imidazole were prepared and antioxidant activity assays (TBARS inhibition, metal chelating activity, free radical scavenging activity) were conducted. The TBARS inhibition of carnosine was due to the imidazole ring present in the histidine and with no inhibition contributed to β-alanine. Metal chelating properties of carnosine was also due to the imidazole ring and not to histidine or β-alanine, while free radical scavenging activity of carnosine was attributed to histidine and not due to imidazole or β-alanine. Overall, results demonstrate that β-alanine and the peptide bond between L- histidine and β-alanine do not play a role in the antioxidant activity of carnosine. Furthermore, results show that  imidazole has antioxidant properties alone, and therefore, it could be used as an antioxidant in various foods and feed applications.