원문정보
초록
영어
Betula platyphylla var. japonica has been used as a Chinese medicine for diuresis and alleviation of pain and fever. Recently antioxidant and anticancer activity were found in the extract from Betula platyphylla var. japonica.1) In order to seek other functions of it, its bark extacted by hot water and methanol, and then we performed some experiments with it. At a non-cytotoxic dose it was found that the extract is effective on inhibition of tyrosinase activity which plays a key role in melanin synthesis. Moreover the extract attenuated the amount of melanin sythesis in B16 melanoma cells. By western blotting we investigated the expression level changes of tyrosinase, TRP1, TRP2 and PAR2, which is related to translocation of melanosome.2) However, there were no differences between the extract-treated cells and control cells in the changes of those expression levels. Taken together, the Betula platyphylla extract has depigmentation activity of skin and the depigmentation mechanism is not to block the translocation of melanosome mediated by PAR2 nor to change the expression level of tyrosinase but to inhibit the activity of tyrosinase.