Antioxidant and fibroblast-activating activities of the by-product of skate chondroitin extractive production

Owing to the increasing popularity of chondroitin sulfate (CS) for joint pain treatment, the CS-production industry has been producing an increasing amount of waste, which includes type II collagen, non-collagenous proteins, and residual CS. To effectively utilize these resources, we intended to develop new products from the by-product of skate chondroitin sulfate production (BP-sCS). In this study, we examined the antioxidant and fibroblast-activating properties of BP-sCS, intending to apply it for a wound-healing promoter. BP-sCS exhibited ABTS and DPPH radical scavenging activities, protected L929 fibroblasts from H2O2- or AAPH-induced oxidative stress, and scavenged intracellular reactive oxygen species. Moreover, BP-sCS promoted L929 fibroblast proliferation/metabolism and stimulated collagen deposition into the extracellular matrix. In addition, BP-sCS counteracted AAPH-induced oxidative stress damage that inhibited fibroblast migration. These effect were attributed to the cooperation among the molecules of BP-sCS, namely, type II collagen peptides, non-collagenous peptides, and CS polysaccharides. Our findings indicate that BP-sCS has the potential as a novel wound-healing promoter. This study is the first step toward the realization of a sustainable CS-production industry by waste utilization in healthcare products