Nutritional supplementation enriched with protein and antioxidants has been demonstrated to effectively strengthen skeletal muscle function and mitigate the risk of sarcopenia. Dietary protein has also been a common carrier to establish bioactive delivery system. Therefore, in this study, a Pickering emulsion delivery system for rutin was constructed with whey protein, and its structural characteristics, bioaccessibility, and molecular interactions were investigated. In the in vivo study, zebrafish (n = 10 in each group), which have a high genetic homology to humans, were treated with dexamethasone to induce sarcopenia symptoms and were administered with rutin, whey protein and the Pickering emulsion, respectively, for muscle movement ability evaluation, and zebrafish treated with or without dexamethasone was used as the model and the control groups, respectively. Results showed that the Pickering emulsion was homogeneous in particle size with a rutin encapsulation rate of 71.16 ± 0.15% and loading efficiency of 44.48 ± 0.11%. Rutin in the Pickering emulsion exhibited a significantly higher bioaccessibility than the free form. The interaction forces between rutin and the two components of whey proteins (α-LA and β-LG) were mainly van der Waals forces and hydrogen bonds. After treatment for 96 h, the zebrafish in Picking emulsion groups showed a significantly increased high-speed movement time and frequency, an increased level of ATP, prolonged peripheral motor nerve length, and normalized muscular histological structure compared with those of the model group (p < 0.05). The results of this study developed a new strategy for rutin utilization and provide scientific evidence for sarcopenia prevention with a food-derived resource.

Background: Rutin (R) is a bioactive compound with antioxidant and anti-inflammatory properties, but its low bioavailability limits its application. To address this problem, R was encapsulated with whey protein (W) as nanoparticles, and the potential effect and mechanism of rutin–whey protein nanoparticles (RW) on skeletal muscle dysfunction was investigated in D-galactose induced mice. Methods: R was encapsulated with W to form RW, and its characteristics like particle size, encapsulation efficiency, and bioaccessibility were evaluated. In the in vivo study, male C57BL/6J mice were treated with R, W or RW, respectively. The muscle function, hepatic antioxidant capacity, serum inflammatory levels, gut microbiota, and metabolomic profiles of mice were evaluated. Results: RW showed a uniform particle size, with an encapsulation efficiency of 68.7%. In the RW, the bioaccessibility of rutin was approximately 3.3 times that of free rutin. This in vivo study indicated that in comparison with D-galactose induced mice (model group), R, W and RW treatments could enhance hepatic antioxidative capacity and regulate inflammation levels, while W and RW could also increase muscle strength. Among these, RW treatment significantly elevated the hepatic GSH-PX activity and decreased the serum MSTN, TNF-α, and IL-6 levels, which were all markedly better than those of the individual effect of R or W. Such effects of R, W, and RW may be achieved through the modulation of gut microbiota that produced short-chain fatty acids or involved in anti-inflammatory function and the regulation of metabolic profiles associated with amino acid metabolism, aminoacyl-tRNA biosynthesis, etc. Conclusions: RW was found to enhance the bioaccessibility of rutin, and exhibited positive effects on skeletal muscle dysfunction via the modulation of gut microbiota and metabolic pathways. The results of this study may provide new scientific strategy for the utilization of rutin to achieve its health benefits.