Wang Luo-Yi, Qin Jun-Jun, Chen Zhen-Hua, Zhou Yu, Tang Wei, Zuo Jian-Ping, Zhao Wei-Min
Department of Natural Product Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, People's Republic of China.
University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, People's Republic of China.
J Nat Prod. 2017 Apr 28;80(4):1102-1109. doi: 10.1021/acs.jnatprod.7b00017. Epub 2017 Mar 15.
Further phytochemical investigation of the root bark of Periploca sepium afforded nine new spiro-orthoester group-containing pregnane-type glycosides termed periplosides O-V and 3-O-formyl-periploside A. The structures of these glycosides along with the absolute configuration of the unique seven-membered formyl acetal-bridged spiro-orthoester function and the 4,6-dideoxy-3-O-methyl-Δ-2-hexosulosyl moiety were elucidated on the basis of spectroscopic data interpretation and chemical transformation. The absolute configurations of the major compounds periplosides C and F were established by single-crystal X-ray diffraction analysis. The isolated compounds were evaluated for their inhibitory activities against the proliferation of T-lymphocytes. As a result, periploside C, the most abundant glycoside containing a spiro-orthoester moiety found in the plant, exhibited the most favorite selective index value (SI = 82.5). The length and constitution of the saccharide chain in the periplosides were found to influence the inhibitory activity and the SI value.
对杠柳根皮进行进一步的植物化学研究，得到了9种新的含螺原酸酯基的孕甾烷型糖苷，命名为杠柳苷O - V以及3 - O - 甲酰基杠柳苷A。基于光谱数据分析和化学转化，阐明了这些糖苷的结构，以及独特的七元甲酰基缩醛桥连螺原酸酯官能团和4,6 - 二脱氧 - 3 - O - 甲基 - Δ² - 己糖醛酸基部分的绝对构型。通过单晶X射线衍射分析确定了主要化合物杠柳苷C和F的绝对构型。对分离得到的化合物进行了抑制T淋巴细胞增殖活性的评估。结果，杠柳苷C是该植物中发现的含螺原酸酯部分最丰富的糖苷，表现出最理想的选择性指数值（SI = 82.5）。发现杠柳苷中糖链的长度和组成会影响其抑制活性和SI值。
