Improved skeletal muscle mass and strength through Protamex-mediated hydrolysis of perilla seed cake: Elevated rosmarinic acid levels as a contributing factor

Perilla seed cake (PSC) is a byproduct of oil extraction from perilla seeds. It is rich in proteins and bioactive compounds. PSC was enzymatically hydrolyzed to form PSC hydrolysate (PSCH) to enhance the absorption of PSC, and their effects on muscle health in mice were compared. High performance liquid chromatography-tandem mass spectrometry analysis revealed that PSC contains several polyphenols, including rosmarinic acid (RA), caffeic acid, apigenin, and luteolin. The hydrolysate showed 1.44- and 7.04-fold increases in RA and caffeic acid contents, respectively, compared to those of PSC. The intake of PSC, PSCH, and RA significantly improved muscle mass and exercise performance in mice by upregulating protein synthesis, myogenic differentiation, oxidative muscle fiber formation, fatty acid oxidation, and mitochondrial biogenesis; however, PSCH had better promoting effects than PSC. In conclusion, PSCH improves muscle health through its bioactive compounds (particularly RA), indicating the potential of PSCH and RA in functional foods.