Phlomis umbrosa Turcz. Water Extract Attenuates Dexamethasone-Induced Muscle Atrophy by Regulating PI3K/Akt/mTOR Pathway

Turcz. water extract (PUW) in mice subjected to dexamethasone-induced muscle atrophy. Mice exhibiting dexamethasone-induced muscle atrophy experienced weight loss, reduced muscle mass, and functional decline. However, PUW administration effectively reversed these effects by maintaining muscle mass and strength, decreasing protein degradation-related marker expression, and enhancing signaling for protein synthesis. Notably, phosphorylations of mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase beta-1, and eukaryotic translation initiation factor 4E-binding protein 1 were significantly enhanced in the PUW group, indicating the activation of anabolic signaling. Overall, PUW alleviates muscle atrophy induced by dexamethasone by modulating the balance between protein degradation and synthesis through regulation of the ubiquitin-proteasome system and phosphoinositide 3-kinase/protein kinase B/mTOR pathway. These findings reveal the potential of PUW as a natural therapeutic agent for preventing or managing muscle wasting.