The objective of the present study was to evaluate the skin whitening effect of the extracts of 3 herbs, Ligularia fischeri, Solidago virga-aurea and Aruncus dioicus, which were collected from Ullung island.Tyrosinase inhibition activities were 33% in pre-fermented extracts and 45% in post-fermented ones. When tyrosinase activities in B16F10 murine melanoma cells were tested, activities in pre-and post-fermented extracts were 41 and 56.5%, respectively. Thus, the post-fermented extracts might have greater skin whitening effects. The protein expression of MITF, TRP-1, TRP-2, and tyrosinase, which are all skin-whitening related transcription factors, showed that both pre-and post-fermented herbs inhibited protein biosynthesis in B16F10 melanoma cells. Post-fermented herb extracts especially showed a greater decrease of protein expressions. The expression of MITF, a regulatory transcription factor, was also decreased by both extracts but was greater in the post-fermented ones. From the results, it can be concluded that the 3 herb extracts from Ullung island may inhibit melanin biosynthesis by the suppression of MITF activity in a signaling pathway. Results indicate that the post-fermented herbs tested in the present study had skin whitening activities and can be used as functional ingredients for food and cosmetic compositions.
The influences of Na and K content on the crystal phase, the microstructure and the electrical property of BaTiO 3 -based thermistors was found to show typical PTC effects. The crystal phase of powder calcined at 1000 o C for 4hrs showed a single phase with BaTiO 3 , and the crystal structure was transformed from tetragonal to cubic phase according to added amounts of Na and K. In XRD results at 43 (002), (020) and (200) peaks. In sintered bodies, those calcined at 600 o C rather than at 1000 o C were dense, and for certain amounts of Na and K showed rapid decreases in grain size. In relative permittivity, the curie temperature due to the transformation of ferroelectric phase rose with added Na and K but decreased in terms of relative permittivity. In the result of the R-T curve, the sintered bodies have curie temperatures of about 140 o C and the resistivity of sintered bodies have scores of Ω·cm; the jump order of sintered bodies was shown to be more than 10 4 in powder calcined at 1000 o C.Key words PTC, Pb-free, heater, BaTiO 3 , Na and K.
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