College of Science and Technology, Nihon University, Tokyo, Japan.
Chem Biodivers. 2012 Jul;9(7):1221-30. doi: 10.1002/cbdv.201100350.
Eight glycosidic compounds, 1-8, including two new compounds, (4ξ)-α-terpineol 8-O-[α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside] (5) and myrtenol 10-O-[β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside] (7), were isolated from the BuOH-soluble fraction of a MeOH extract of Momordica charantia leaves. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of compounds 1-8 on the melanogenesis in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), these compounds were found to exhibit inhibitory activities with 7.1-27.0% and 23.6-46.4% reduction of melanin content at 30 μM and 100 μM, respectively, with no or almost no toxicity to the cells (80.0-103.5% of cell viability at 100 μM). Western blot analysis showed that compound 7 reduced the protein levels of MITF, tyrosinase, TRP-1, and TRP-2 mostly in a concentration-dependent manner, suggesting that this compound inhibits melanogenesis on the α-MSH-stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase, TRP-1, and TRP-2.
从苦瓜叶的甲醇提取物的 BuOH 可溶部分分离得到了 8 个糖苷化合物，包括 2 个新化合物，(4ξ)-α-松油醇 8-O-[α-L-阿拉伯吡喃糖基-(1→6)-β-D-吡喃葡萄糖苷] (5) 和桃金娘烯醇 10-O-[β-D-阿比呋喃糖基-(1→6)-β-D-吡喃葡萄糖苷] (7)。新化合物的结构是基于广泛的光谱分析和与文献比较来阐明的。在评价化合物 1-8 对 α-促黑素细胞激素 (α-MSH) 诱导的 B16 黑色素瘤细胞的黑色素生成的影响时，发现这些化合物在 30 μM 和 100 μM 时分别具有 7.1-27.0%和 23.6-46.4%的黑色素含量抑制活性，且对细胞没有毒性或几乎没有毒性 (在 100 μM 时细胞活力为 80.0-103.5%)。Western blot 分析表明，化合物 7 主要以浓度依赖的方式降低 MITF、酪氨酸酶、TRP-1 和 TRP-2 的蛋白水平，表明该化合物通过至少部分抑制 MITF 的表达，随后降低酪氨酸酶、TRP-1 和 TRP-2 的表达，抑制 α-MSH 刺激的 B16 黑色素瘤细胞中的黑色素生成。
