5,7-Dimethoxyflavone Attenuates Sarcopenic Obesity by Enhancing PGC-1α-Mediated Mitochondrial Function in High-Fat-Diet-Induced Obese Mice.

Background/Objectives: Sarcopenic obesity, defined by the coexistence of excessive fat accumulation and progressive muscle loss, is associated with an increased risk of metabolic dysfunction and physical disability. While 5,7-dimethoxyflavone (DMF), a bioactive flavone derived from Kaempferia parviflora, has demonstrated anti-obesity and muscle-preserving properties, its effects on sarcopenic obesity remain unclear. Methods: Four-week-old male C57BL/6J mice were fed a high-fat diet (HFD) for 6 weeks to induce sarcopenic obesity, followed by 8 weeks of continued HFD with the oral administration of DMF. Muscle function was assessed through grip strength and treadmill running tests, while muscle and fat volumes were measured using micro-CT. Mechanistic analyses were performed using gene expression and Western blot analysis. Results: DMF significantly reduced body weight, fat mass, and adipocyte size while enhancing grip strength, endurance, skeletal muscle mass, and the muscle fiber cross-sectional area. In the gastrocnemius muscle, DMF increased the gene expression of peroxisome proliferator-activated receptor gamma coactivator-1α (Ppargc1a) and its isoform Ppargc1a4, thereby promoting mitochondrial biogenesis. It also improved protein turnover by modulating protein synthesis and degradation via the phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin signaling pathway. In subcutaneous and brown adipose tissues, DMF increased mitochondrial DNA content and the expression of thermogenic and beige adipocyte-related genes. These findings suggest that DMF alleviates sarcopenic obesity by improving mitochondrial function and regulating energy metabolism in both skeletal muscle and adipose tissues via PGC-1α-mediated pathways. Thus, DMF represents a promising therapeutic candidate for the integrated management of sarcopenic obesity.