Kai Hisahiro, Baba Masaki, Okuyama Toru
Department of Natural Medicine and Phytochemistry, Meiji Pharmaceutical University, Tokyo, Japan.
Planta Med. 2008 Dec;74(15):1785-8. doi: 10.1055/s-0028-1088338. Epub 2008 Nov 13.
We compared the inhibitory effects on melanogenesis of six plant parts (leaves, stems, roots, whole fruits, calyxes, and fruits without calyxes) of Cucumis sativus. MeOH extracts of leaves and stems inhibited melanin production in B16 cells. These extracts did not affect the activity of mushroom tyrosinase or crude enzyme lysate from B16 cells. However, the extracts decreased tyrosinase expression at the protein level. These results suggest that the depigmenting mechanism of extracts from leaves and stems of C. SATIVUS involves the expression of tyrosinase. Of eight compounds isolated from the leaves, lutein ( 1) (IC (50) = 170.7 microM) and (+)-(1 R,2 S,5 R,6 S)-2,6-di-(4'-hydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane ( 2) (IC (50) = 270.8 microM) were found to suppress melanogenesis. Whereas 1 was found to markedly decrease the expression levels of tyrosinase, 2 only weakly reduced tyrosinase expression. This suggests that 1 is an active component in the leaves of C. sativus and is a potentially useful skin-whitening agent.
我们比较了黄瓜六个植物部位（叶、茎、根、整果、花萼和去花萼果实）对黑色素生成的抑制作用。叶和茎的甲醇提取物抑制了B16细胞中的黑色素生成。这些提取物不影响蘑菇酪氨酸酶或B16细胞粗酶裂解物的活性。然而，提取物在蛋白质水平上降低了酪氨酸酶的表达。这些结果表明，黄瓜叶和茎提取物的色素沉着机制涉及酪氨酸酶的表达。从叶中分离出的八种化合物中，叶黄素（1）（IC50 = 170.7 microM）和（+）-（1R，2S，5R，6S）-2,6-二-（4'-羟基苯基）-3,7-二氧杂双环[3.3.0]辛烷（2）（IC50 = 270.8 microM）被发现可抑制黑色素生成。虽然发现1可显著降低酪氨酸酶的表达水平，但2仅微弱降低酪氨酸酶的表达。这表明1是黄瓜叶中的活性成分，是一种潜在有用的皮肤美白剂。
