Skin and Skin Care
Depigmenting extracts: Hwang et al. have published on the inhibitory effects of plant extracts on tyrosinase, l-DOPA oxidation and melanin synthesis. For medical, pharmacological and cosmetic reasons, the demand for effective and safe depigmenting agents has increased. In this study, 101 plant extracts in methanol or water were screened for their inhibitory activities against tyrosinase, l- DOPA oxidation, and melanin biosynthesis in B16 mouse melanoma cells. Of the extracts examined, 31 showed a more than 50% inhibition of mushroom tyrosinase at a concentration of 666 μg/mL; 11 extracts inhibited l- DOPA auto-oxidation at this concentration.
In particular, leaves and stem extracts of Broussonetia kazinoki var. humilis, leaves and bark extracts of Broussonetia papyrifera, Cornus officinalis fruit extract, Rhus javanica gallnut extracts and Pinus densiflora leaves extract inhibited both tyrosinase activity and l-DOPA oxidation in a concentration-dependent manner.
Seventeen plant extracts that inhibited tyrosinase were further tested for their inhibitory effects on melanogenesis. In B16 mouse melanoma cells, extracts of Acorus gramineus, Capsella bursa-pastoris, Morus bombycis, Perilla frutescens var. crispa, Quercus dentate bark extract, Rhus javanica (gallnut), Schizopepon bryoniaefolius or Sophora flavescens markedly inhibited, by >50%, melanin synthesis at 50 μg/mL. These plants represent a potential source of novel whitening agents for UV-sensitive skin.
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