The Skin-Whitening Effects of Padina Gymnospora and Its Active Compound, Fucosterol

Padina gymnospora is a brown algae of the class Phaeophyceae. It has been established that P. gymnospora ameliorates amyloid-β-induced neuropathology and has an anticoagulation effect, but this study was designed to estimate its skin-whitening effect and identify its active component. The ingredients of P. gymnospora were extracted with ethanol and its activity was compared with arbutin. First, the P. gymnospora extract was observed to inhibit tyrosinase activity in a dose-dependent manner, tyrosinase being the rate-limiting enzyme of melanin synthesis. Notably, where 200 μM of arbutin inhibited tyrosinase activity by 58.1%, P. gymnospora extract (0.5%) achieved 76.7%. The P. gymnospora extract also significantly reduced α-melanocyte-stimulating hormone-induced TRP-1 and TRP-2 mRNA expression. In addition, it significantly inhibited melanin synthesis in B16F10 melanoma cells. We identified the 0.66% fucosterol content that inhibited melanin synthesis as comparable to that of arbutin. Additionally, we tested the potential cytotoxicity of P. gymnospora by MTT and LDH release assay and found that the extract significantly reduced LDH release in CCD-986sk cells. These results indicate that P. gymnospora extract could be a potential active ingredient of cosmetics with a skinwhitening effect.