The antioxidant capacity evaluation of polysaccharide hydrolyzates from pumpkin using Caenorhabditis elegans model

Our previous study has optimized the acid hydrolysis process of pumpkin polysaccharides (PPe) with scavenging ability based on central composite design. The aim of this study was to explore the in vivo-antioxidant ability of PPe and pumpkin polysaccharides acid-hydrolysis (PPe-S) using Caenorhabditis elegans. In composition analysis, the constituents of total sugar, protein, uronic acid, and sulfur groups in PPe-S were 87.03 ± 1.21%, 1.25 ± 0.78%, 37.61 ± 0.97%, and 0.14 ± 0.04%, respectively. Besides, results of antioxidant ability showed that PPe and PPe-S could reduce the oxidative stress (OS) induced by methyl viologen, extend lifespan of worms, and reduce reactive oxygen species (ROS) level under oxidative conditions significantly (p < .05). Furthermore, PPe and PPe-S could enhance the stress-resistance related antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) significantly (p < .05). Moreover, the antioxidant effect of PPe-S was superior to PPe at the concentration of 4.0 mg/ml. In summary, this study demonstrated that the derived hydrolyzates from PPe had protective effects on the damage induced by the generation of intracellular free radical agents. PRACTICAL APPLICATIONS: OS plays an important role in the pathogenesis of metabolic diseases, including type 2 diabetes. It is widely acknowledged that diabetes and its complications pose a threat to human's health, and the number of people with diabetes will expand to 640 million in the 2040 year. Current studies have shown that all diabetes drugs have a kind of side effects. Fortunately, researchers have found and confirmed that plant-derived polysaccharide had a notable hypoglycemic effect via reducing the OS level in cell and tissue, and could decrease the diabetes symptoms as well. In this study, we proved that the polysaccharide derived from pumpkin could effectively ameliorate the OS level in C. elegans, including decreasing the damage of biofilm and ROS level. Therefore, our study shows that there is a high potential for pumpkin-derived polysaccharide and its hydrolyzates to be a bioactive component to prevent diabetes. In other words, this research can be applied to diabetes prevention and other diseases induced by OS.