Depigmenting Effect of Winter Medicinal Mushroom Flammulna velutipes (Higher Basidiomycetes) on Melanoma Cells.

In humans, skin pigmentation results from the biochemichal synthesis and accumulation of melanin. We previously revealed that edible winter mushroom Flammulina velutipes extract inhibited melanosis in commercially available edible crustacea. Therefore, the current study was conducted to find if edible mushrooms extracts are useful for the skin whitening and the underlying mechanisms in melanin biosynthesis. Tyrosinase is one of the key enzymes for melanin biosynthesis. This study demonstrated that melanin synthesis and tyrosinase activity were suppressed by the F. velutipes extracts in B16 murine melanoma cells through the slow expression of microphthalmia-associated transcription factor. These results suggested that the F. velutipes extract could contain an effective component in whitening cosmetics and an alternative therapeutic agent for treating hyperpigmentation.

Preparation of organic/inorganic composites by deposition of silica onto shell layers of polystyrene (core)/poly[2-(N,N-dimethylamino)ethyl methacrylate] (shell) particles.

Organic/inorganic composites were prepared by catalytic hydrolysis and subsequent condensation of tetraethoxysilane (TEOS) in a shell layer of core-shell polymer particles. First, core-shell particles were prepared by emulsifier-free emulsion polymerization of styrene (St) with 2-chloropropionyloxyethyl methacrylate (CPEM) using potassium persulfate as an initiator, followed by surface-initiated activator generated electron transfer-atom transfer radical polymerization (AGET-ATRP) of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA). Dynamic light scattering revealed that hydrodynamic diameter of the particle increased from 482 to 931 nm after AGET-ATRP of DMAEMA. The amount of grafted DMAEMA was determined to be ca. 10 mol% with respect to (wrt) St by (1)H NMR. Second, the composite particles were prepared by adding TEOS into a water/methanol dispersion of the P(St-CPEM)-g-P(DMAEMA). The P(St-CPEM)-g-P(DMAEMA)-SiO(2) composite particles containing ca. 50 wt.% of silica wrt the total weight were obtained. Hollow silica shell particles were also obtained by extraction of polymer components from the composites with tetrahydrofuran.