Quercetin supplementation and muscular atrophy in animal models: A systematic review and meta-analysis

Muscle atrophy is a degenerative condition characterized by secondary inflammation, free radical injury, and metabolic dysregulation. Evidence regarding the effects of quercetin on skeletal muscle atrophy is currently controversial and unclear. We hypothesized that quercetin, a anti-inflammatory and antioxidant properties phytochemical, may play an important role in muscle atrophy, and we conducted a comprehensive systematic review and meta-analysis to summarize the effects of quercetin supplementation on muscular atrophy based on studies performed in animal models. Three atrophy biomarkers (muscle mass, fiber size, and function) with enough eligible studies (n = 6, 7, and 4, respectively) were combined in the final meta-analysis. Next, we calculated the overall and stratified effects of quercetin administration on muscular atrophy. No significant effects were observed on muscle mass and muscle function; however, we observed protective effects of quercetin on muscle fiber diameter and area [(Standardized Mean Difference (SMD): 0.82, 95% Confidence interval (CI): 0.36, 1.28), and (SMD: 0.94, 95% CI: 0.25, 1.62), respectively]. This study suggests that quercetin could have histological protection effect on muscle fiber. Thus, it could become a promising complementary therapy for muscle atrophy that occurs due to various clinical conditions. Abbreviations: SMD, Standardized Mean Difference; CI, Confidence interval; PRISMA-P, Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols; Nrf2, nuclear factor erythroid 2-related factor; HO-1, heme oxygenase-1; PPAR-γ, peroxisome proliferator-activated receptor-γ; SIRT-1, silent mating type information regulator 2 homolog 1; PGC-1α, PPAR-γ coactivator-1α; FABP4, fatty acid binding protein 4; DMD, Duchenne muscular dystrophy