Bioassay-guided fractionation of the methanolic extract from the roots of Cynanchum atratum has resulted in the isolation of three new pregnane glycosides (1–3) along with four known compounds (4–7). Their structures were identified by analysis of the spectroscopic data including extensive 2D NMR. All of the isolates were evaluated for their potential to inhibit the melanin production in α-melanocyte stimulating hormone (α-MSH)-activated B16 melanoma cells. Of these, compounds 4–7 dose-dependently inhibited the melanin production with the IC₅₀ values ranging from 4 μM to 33 μM.

中文翻译：

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从黑素生成抑制孕苷徐长卿atratum

从根部的甲醇提取物的生物测定引导的分级分离牛心atratum导致的三个新孕甙（隔离1 - 3）具有四个已知化合物（沿4 - 7）。通过分析光谱数据（包括广泛的2D NMR）确定了它们的结构。对所有分离物在α-黑素细胞刺激激素（α-MSH）激活的B16黑色素瘤细胞中抑制黑色素生成的潜力进行了评估。这些当中，化合物4 - 7剂量依赖性地抑制黑色素产生与IC ₅₀值范围从4μM至33μM。