合欢皮中的三萜皂苷

Triterpenoid Saponins from Cortex Albiziae

合欢皮作为传统中药,为豆科植物合欢的干燥茎皮。在1995年版中国药典中记载合欢皮具有解郁安神、活血化瘀的作用。在我们对传统中药品质进行研究的过程中,通过对合欢皮95%乙醇提取物的正丁醇可溶部位进行一系列溶剂处理和层析分离,分离获得28个五环三萜皂苷。基于化学和波谱证据,我们鉴定了它们的结构,包括6对非对映异构体、5对位置异构体,其中26个皂苷为新化合物。所有分离皂苷均为三糖链皂苷,含有金合欢酸皂苷元,7～9个单糖和1～2个单萜酸酯衍生物,分子量大于2000。根据它们的一维、二维核磁共振数据归属了这些皂苷的所有碳信号和大多数质子信号,并修订了几个已知皂苷的碳氢谱数据,在此基础上,总结了这类皂苷的波谱规律。本文同时讨论了这些皂苷及其类似物的细胞毒活性和其它活性。

Cortex Albiziae, the dried stem bark of a leguminous plant, Albizia julibrissin Durazz, was specified in Chinese Pharmacopoeia （ 1995 edit. ） as a traditional Chinese medicine to be used to relieve melancholia and uneasiness of body and mind, to invigorate the circulation of blood and subside a swelling. In a course of our quality assessment of traditional Chinese medicines, the n-BuOH soluble part of 95% EtOH extracts from the stem barks of Albizia julibrissin was subjected to a series of solvent treatment and chromatographic separations, including Rp-HPLC methods, giving rise to 28 pentacyclic triterpenoid saponins. Based on chemical methods and spectroscopic evidences, the structures of saponins were identified, which included six pairs of diastereoisomers, five pairs of position isomers, and 26 of them were new compounds. All the saponins are trisdesmosidic saponins, which are composed of an acacic acid moiety, 7 -9 monosaccharide moieties, 1 - 2 monoterpenic acid moieties, and exhibited their molecular ion peaks around m/z 2 000. Their carbon-13 signals and most of proton signals were assigned based on 1 D and 2D NMR experiments. Theproton and carbon signals of several known saponins were revised and reassigned. The spectroscopic properties related to these saponins were analyzed and summarized. The cytotoxic activity and other activities of these saponins and their analogues were discussed also.