Extract of Alnus japonica prevents dexamethasone-induced muscle atrophy in mice

• Published in: Journal of functional foods Vol. 101; p. 105419
• Main Authors: Lee, Hyejin, Seon Lee, Kyeong, Hye Jeong, Ji, Soo Yoon, Ji, Hwan Hwang, Seung, Kim, Sang-Yoon, Hum Yeon, Sung, Ryu, Jae-Ha
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023; Elsevier
• Subjects: Alnus japonica; C2C12; Dexamethasone; Muscle atrophy; Oregonin; Sarcopenia; Sarcopenia; Muscle atrophy; C2C12; Alnus japonica; Dexamethasone; Oregonin
• ISSN: 1756-4646; 2214-9414
• DOI: 10.1016/j.jff.2023.105419

Anti-myopathy activity of A. japonica in vivo and in vitro [Display omitted] •We identified a diarylheptanoid, oregonin, from extracts of Alnus japonica (AJE) that can inhibit muscle atrophy.•AJE improved muscle strength and increased muscle mass in dexamethasone-induced muscle atrophy mouse model.•AJE prevented muscle atrophy via downregulating protein-degradative factors (MuRF1, MAFbx, Myostatin, and FOXO3a) in muscle.•AJE and oregonin, as a myogenic constituent of AJE, promoted myoblast differentiation and prevented myotube loss by increasing mTOR pathway and decreasing catabolic factors in vitro. As part of our effort to search for food ingredients with ability to inhibit muscle wasting, we found that extract of Alnus japonica (AJE) and its main constituent, oregonin, could prevent muscle atrophy from in vitro and in vivo studies. Oregonin rich extract of AJ improved muscle strengths of dexamethasone-induced atrophied mice as evidenced by decreased expression of muscle protein-degradative factors and increased muscle mass. In C2C12 myoblasts, oregonin stimulated myogenesis, showing increased expression of MHC and myogenin via p38 mitogen-activated protein kinase (MAPK) activation. In differentiated myotubes, AJE and oregonin protected against dexamethasone-induced loss of myotubes by suppressing expressions of MAFbx and MuRF1, while increasing MHC expression and mTOR phosphorylation. These dual effects of oregonin might have contributed to its ability to protect against loss of myotubes. Taken together, our results suggest that AJE has a favorable alleviating effect on sarcopenia via regulation of muscle protein synthesis and degradation.