School of Pharmacy, Nanchang University, 461 Bayi Road, Nanchang 330006, People's Republic of China.
Center of Analysis and Testing, Nanchang University, Nanchang 330047, People's Republic of China.
Fitoterapia. 2018 Oct;130:241-246. doi: 10.1016/j.fitote.2018.09.001. Epub 2018 Sep 6.
Three new cholestane-type sterols bearing an unusual ∆-24-oxo side chain, namely, dictyoptesterols A-C (1-3), were isolated from the brown alga Dictyopteris undulata Holmes, together with five known strutural analogues (4-8). Their structures were elucidated on the basis of by extensive spectroscopic analysis. The absolute configurations of the steroidal nuclei of the new compounds were proposed by a comparison of NMR data with those of related known compounds as well as biogenetic considerations. All of the isolates were evaluated in vitro for their potential to inhibit protein tyrosine phosphatase-1B (PTP1B) activity. The results showed that compounds 1-5 exhibited different levels of PTP1B inhibitory activities with IC values ranging from 3.03 ± 0.76 to 15.01 ± 2.88 μM. In particular, compounds 3 and 4 showed promising inhibitory effects towards PTP1B with IC values of 3.03 ± 0.76 and 3.72 ± 0.40 μM, respectively, when compared to the positive control oleanolic acid (IC, 2.83 ± 0.39 μM). The chemotaxonomic significance of these isolated ∆-24-oxo cholestanes has also been discussed.
从褐藻 Dictyopteris undulata Holmes 中分离得到了三种具有不寻常 ∆-24-氧代侧链的新胆甾烷型甾醇，分别为 dictyoptesterols A-C（1-3），此外还分离得到了五种已知结构类似物（4-8）。通过广泛的光谱分析确定了它们的结构。根据与相关已知化合物的 NMR 数据以及生物发生考虑，提出了新化合物甾核的绝对构型。所有分离物均在体外评估了其抑制蛋白酪氨酸磷酸酶-1B（PTP1B）活性的潜力。结果表明，化合物 1-5 表现出不同程度的 PTP1B 抑制活性，IC 值范围为 3.03±0.76 至 15.01±2.88 μM。特别是，化合物 3 和 4 对 PTP1B 表现出有希望的抑制作用，IC 值分别为 3.03±0.76 和 3.72±0.40 μM，与阳性对照齐墩果酸（IC，2.83±0.39 μM）相比。还讨论了这些分离的 ∆-24-氧代胆甾烷的化学生态学意义。
