Anti-aging and Antioxidant Activities of Hydrolysate Fraction from Spherical Sea Cucumber (Phyllophorus proteus) in Caenorhabditis elegans

To explore anti-aging and antioxidant activities of Phyllophorus proteus hydrolysate fraction (PPHF) on Caenorhabditis elegans, the physiological and biochemical indicators of C. elegans fed 0.5, 2.0 mg/mL and 8.0 mg/mL PPHF were determined. The results showed that PPHF was beige in color, and its L^* and b^* values were 81.28 and 15.88, respectively. The proportion of oligopeptides with molecular mass of 180–1000 Da in PPHF was 63.76%, and the proportions of glutamic acid and glycine were 19.50% and 15.34%, respectively. After being fed 0.5, 2.0, and 8.0 mg/mL PPHF, the lifespan of C. elegans was increased by 22.43%, 54.60%, and 78.89%, respectively, under normal conditions, and also increased under thermal or oxidative stress. The body length of C. elegans was increased significantly by feeding 0.5 mg/mL PPHF, while the swallowing frequency was significantly increased by feeding 2.0 mg/mL PPHF. The body bending frequency of C. elegans fed 0.5 and 8.0 mg/mL PPHF was increased by 7.75% and 43.71%, respectively, when compared with the control group on the second day of incubation. PPHF significantly reduced the content of reactive oxygen species (ROS) in C. elegans, and increased the antioxidant enzyme activity, glutathione content and total antioxidant capacity in a dose-dependent manner. These results indicated that PPHF could improve the physiological function and prolong the lifespan by enhancing antioxidant capacity in C. elegans.