Hirtionosides A–C, gallates of megastigmane glucosides, 3-hydroxyoctanoic acid glucosides and a phenylpropanoid glucoside from the whole plants of Euphorbia hirta
作者:Yuya Nomoto、Sachiko Sugimoto、Katsuyoshi Matsunami、Hideaki Otsuka
DOI:10.1007/s11418-012-0692-5
日期:2013.4
From the 1-BuOH-soluble fraction of a MeOH extract of Euphorbia hirta, collected in the Okinawa islands, three new megastigmane glucoside gallates, named hirtionosides A–C, 3-hydroxyoctanoic acid glucosides and a phenylpropanoid glucoside were isolated along with 15 known compounds. The structures of the new compounds were elucidated by detailed analysis of physical data, including one- and two-dimensional NMR spectra, and those of known compounds were determined by comparison of physico-chemical data with those reported in the literature. The absolute structures of the megastigmanes were determined by comparison of NMR data and Cotton effects in the CD spectra. The modified Mosher’s method was applied to determine the absolute structure of the chiral center in 3-hydroxyoctanoic acid. The DPPH radical-scavenging properties of megastigmane glucoside gallates were assayed and, as expected, they showed moderate activity.
从收集于冲绳群岛的乳草(Euphorbia hirta)的甲醇提取物的1-丁醇可溶性部分中,分离出了三种新的大痕基苷酸(megastigmane glucoside gallates),命名为hirtionosides A–C、3-羟基辛酸葡萄糖苷以及一种苯丙烯酸葡萄糖苷,并且还分离出15种已知化合物。通过对物理数据的详细分析,包括一维和二维核磁共振(NMR)谱,阐明了新化合物的结构,而已知化合物的结构则通过与文献中报告的物理化学数据的比较来确定。通过比较核磁共振数据和圆二色性(CD)谱中的Cotton效应,确定了大痕基的绝对结构。采用改进的Mosher方法确定了3-羟基辛酸中的手性中心的绝对结构。对大痕基苷酸的DPPH自由基清除能力进行了测定,结果如预期显示出适度的活性。