Skin healthcare protection with antioxidant and anti-melanogenesis activity of polysaccharide purification from Bletilla striata

In this study, we investigated the structural characterization and biological activities of Bletilla striata polysaccharides (BSPs) for their role as antioxidants and anti-melanogenesis agents in skin healthcare protection. Three neutral polysaccharides (BSP-1, BSP-2, and BSP-3) with molecular weights of 269.121 kDa, 57.389 kDa, and 28.153 kDa were extracted and purified. Their structural characteristics were analyzed by ion chromatography, GC–MS, and 1D/2D NMR. The results showed that BSP-1, which constitutes the major part of BSPs, was composed of α-D-Glcp, β-D-Glcp, β-D-Manp, and 2-O-acetyl-β-D-Manp, with the branched-chain accompanied by β-D-Galp and α-D-Glcp. BSP-1, BSP-2, and BSP-3 can enhance the total antioxidant capacity of skin fibroblasts with non-toxicity. Meanwhile, BSP-1, BSP-2, and BSP-3 could significantly inhibit the proliferative activity of melanoma cells. Among them, BSP-1 and BSP-2 showed more significance in anti-melanogenesis, tyrosinase inhibition activity, and cell migration inhibition. BSPs have effective antioxidant capacity and anti-melanogenesis effects, which should be further emphasized and developed as skin protection components.