Yusuke Iwasaki¹, Hiroyasu Sakai², Maho Asami², Satoko Kitora², Hiroaki Naito², Risako Kon², Nobutomo Ikarashi², Junzo Kamei^{1, 2,}

In patients with inflammatory diseases, exogenous glucocorticoids have become the most common cause of drug-induced muscle wasting. In this study, we showed that isoleucine-arginine (IR) and arginine-isoleucine (RI) are the main dipeptides with antioxidant activity in fish meat-derived peptide extract (FMDP). To investigate the anti-fatigue effect of FMDP and the two dipeptides (IR or RI), dexamethasone (DEX)-treated mice performed a weighted forced swimming test. Despite no change in body weight, the shortened swim time after DEX administration returned to baseline levels following the administration of FMDP, IR, and RI. However, the swim time of naive mice cannot be extended with the administration of FMDP, IR, or RI. Our data suggest that FMDP, IR, and RI may have beneficial effects on DEX-induced fatigue in mice. Nevertheless, further research is required to determine the mechanism through which FMDP reduces fatigue.

antioxidant activity, fish meat-derived peptide, dexamethasone, fatigue, electron spin resonance