Department of Chemistry, Faculty of Science, University of Dschang, Box 183, Dschang, Cameroon.
Phytochemistry. 2010 Dec;71(17-18):2108-15. doi: 10.1016/j.phytochem.2010.08.020. Epub 2010 Sep 16.
Three saponins, including two dimeric triterpenoid glucosides possessing an unusual skeleton, ivorenosides A and B, and a monomeric triterpenoid saponin (ivorenoside C), together with the known sericoside, were isolated from the bark of Terminalia ivorensis. Their structures were established on the basis of 1D and 2D NMR data, chemical methods and tandem MS-MS spectrometry as a dimer of β-D-glucopyranosyl-18,19-seco-2α,3β,19,19,24-pentahydroxyolean-12-en-28-oate and β-D-glucopyranosyl-2α,3β,19α,24-tetrahydroxyolean-12-en-28-oate (ivorenoside A, 1), a dimer of β-D-glucopyranosyl-18,19-seco-24-carboxyl-2α,3β,19,19-tetrahydroxyolean-12-en-28-oate and β-D-glucopyranosyl-2α,3β,19α,24-tetrahydroxyolean-12-en-28-oate (ivorenoside B, 2) and β-D-glucopyranosyl-2α,3β,19β,24-tetrahydroxyolean-11-oxo-olean-12-en-28-oate (ivorenoside C, 3). Ivorenosides A and B are the first examples in nature of dimeric triterpenoid saponins with a 18,19-seco E ring of one of the two units. These isolated compounds were evaluated for their antioxidant properties and further for their cytotoxic activity against four human cancer cell lines. Ivorenoside B and C exhibited scavenging activity against DPPH and ABTS(+) radicals with IC(50) values comparable with that of the standard drug Trolox and ivorenoside A showed antiproliferative activity against MDA-MB-231 and HCT116 human cancer cell lines with IC(50) values of 3.96 and 3.43 μM, respectively.
从Terminalia ivorensis 的树皮中分离得到了三种皂角苷，包括两种具有不寻常骨架的二聚体三萜糖苷 ivorenosides A 和 B，以及一种单体三萜皂苷（ivorenoside C），以及已知的丝氨酸糖苷。根据 1D 和 2D NMR 数据、化学方法和串联 MS-MS 光谱，它们的结构被确定为β-D-吡喃葡萄糖基-18,19-断环-2α,3β,19,19,24-五羟基齐墩果-12-烯-28-酸酯和β-D-吡喃葡萄糖基-2α,3β,19α,24-四羟基齐墩果-12-烯-28-酸酯的二聚体（ivorenoside A，1），β-D-吡喃葡萄糖基-18,19-断环-24-羧酸-2α,3β,19,19-四羟基齐墩果-12-烯-28-酸酯和β-D-吡喃葡萄糖基-2α,3β,19α,24-四羟基齐墩果-12-烯-28-酸酯的二聚体（ivorenoside B，2）和β-D-吡喃葡萄糖基-2α,3β,19β,24-四羟基齐墩果-11-氧代-齐墩果-12-烯-28-酸酯（ivorenoside C，3）。Ivorenosides A 和 B 是自然界中第一个具有两个单元之一的 18,19-断环 E 环的二聚体三萜皂苷。对这些分离得到的化合物进行了抗氧化性能评价，并进一步评价了它们对四种人癌细胞系的细胞毒性活性。Ivorenoside B 和 C 对 DPPH 和 ABTS(+)自由基具有清除活性，其 IC(50)值与标准药物 Trolox 相当，而 ivorenoside A 对 MDA-MB-231 和 HCT116 人癌细胞系的增殖活性具有抑制作用，其 IC(50)值分别为 3.96 和 3.43 μM。
