Imidazole dipeptides, which are abundant in meat and fish, are substances produced in the bodies of various animals, including humans, and have been reported to be effective in relieving fatigue and preventing dementia. However, the physiological mechanism by which IDPs exhibit these activities had not been determined previously.

A research team, led by Professor Hideshi Ihara from the Osaka Metropolitan University Graduate School of Science, was the first to discover 2-oxo-imidazole-containing dipeptides —which have one more oxygen atom than normal IDPs—and found that they are the most common variety of IDPs derivatives in the body. The researchers also found that they have remarkably high antioxidant activity.

In their study, the researchers established a method for selective and highly sensitive detection of five types of 2-oxo-IDPs using mass spectrometry, which enables quantitative detection of trace 2-oxo-IDPs in living organisms. Using this method, they revealed for the first time that beef, pork, chicken and other meats contain antioxidants, not only IDPs but a variety of different 2-oxo-IDPs. Their findings were published in Antioxidants.

"We hope that this research method, which enables advanced analysis of 2-oxo-IDPs, will be applied not only to basic biology but also to medicine, agriculture and pharmacy, where it will help improve peoples' health and prevent diseases," concluded Professor Ihara.

This work was supported in part by Grant-in-Aid for Scientific Research (S, B and C) 17H06170, 21H02082, 19K06537 and 22K06148, Grant-in-Aid for Challenging Exploratory Research 20K21256 and 22K19159, Grant-in-Aid for Scientific Research on Innovative Areas "Oxygen Biology: a new criterion for integrated understanding of life" 26111011 from the Japanese Ministry of Education, Sciences, Sports, Technology.