State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing 100050, People's Republic of China.
J Nat Prod. 2012 Jul 27;75(7):1373-82. doi: 10.1021/np300310a. Epub 2012 Jul 10.
Nine new dammarane triterpene glycosides (1-3 and 8-13) and 12 known analogues have been isolated from an ethanol extract of the roots of Machilus yaoshansis. Compounds 1-7 have an uncommon 20,23-dihydroxydammar-24-en-21-oic acid-21,23-lactone moiety that was previously reported in compounds isolated from Gynostemma pentaphyllum. The configurations of the lactone moieties in 1-3 were determined by comparison of the experimental ECD spectra of 1-3 and the hydrolysates, 1a and 1b, with the corresponding calculated ECD spectra. On the basis of NMR and ECD data analysis of 1-7, the previously reported C-20 and C-23 configurations of 4-7 and related derivatives from Gynostemma pentaphyllum were revised. In addition, the application of NMR data and Cotton effects to the determination of the relative and absolute configurations of the γ-lactone moiety in 3β,20,23-trihydroxydammar-24-en-21-oic acid-21,23-lactone derivatives is discussed.
从杨桐根的乙醇提取物中分离得到了 9 种新的达玛烷三萜糖苷（1-3 和 8-13）和 12 种已知类似物。化合物 1-7 具有一个不常见的 20,23-二羟基达玛-24-烯-21-酸-21,23-内酯部分，该部分以前在从绞股蓝中分离得到的化合物中有所报道。通过比较 1-3 的实验 ECD 光谱与其水解产物 1a 和 1b 以及相应的计算 ECD 光谱，确定了 1-3 中内酯部分的构型。基于对 1-7 的 NMR 和 ECD 数据分析，修订了 4-7 和相关绞股蓝衍生物中以前报道的 C-20 和 C-23 构型。此外，还讨论了 NMR 数据和 COTTON 效应在确定 3β,20,23-三羟基达玛-24-烯-21-酸-21,23-内酯衍生物中γ-内酯部分的相对和绝对构型中的应用。
