Irungu Beatrice N, Orwa Jennifer A, Gruhonjic Amra, Fitzpatrick Paul A, Landberg Göran, Kimani Francis, Midiwo Jacob, Erdélyi Máté, Yenesew Abiy
Kenya Medical Research Institute, Centre for Traditional Medicine and Drug Research, P.O. Box 54840-00200, Nairobi 00200, Kenya.
Sahlgrenska Cancer Centre, University of Gothenburg, Gothenburg SE-405 30, Sweden.
Molecules. 2014 Sep 10;19(9):14235-46. doi: 10.3390/molecules190914235.
A new triterpenoid, 3-oxo-12β-hydroxy-oleanan-28,13β-olide (1), and six known triterpenoids 2-7 were isolated from the root bark of Ekebergia capensis, an African medicinal plant. A limonoid 8 and two glycoflavonoids 9-10 were found in its leaves. The metabolites were identified by NMR and MS analyses, and their cytotoxicity was evaluated against the mammalian African monkey kidney (vero), mouse breast cancer (4T1), human larynx carcinoma (HEp2) and human breast cancer (MDA-MB-231) cell lines. Out of the isolates, oleanonic acid (2) showed the highest cytotoxicity, i.e., IC50's of 1.4 and 13.3 µM against the HEp2 and 4T1 cells, respectively. Motivated by the higher cytotoxicity of the crude bark extract as compared to the isolates, the interactions of oleanonic acid (2) with five triterpenoids 3-7 were evaluated on vero cells. In an antiplasmodial assay, seven of the metabolites were observed to possess moderate activity against the D6 and W2 strains of P. falciparum (IC50 27.1-97.1 µM), however with a low selectivity index (IC50(vero)/IC50(P. falciparum-D6)<10). The observed moderate antiplasmodial activity may be due to general cytotoxicity of the isolated triterpenoids.
从非洲药用植物卡氏米仔兰的根皮中分离出一种新的三萜类化合物3-氧代-12β-羟基齐墩果-28,13β-内酯（1）以及六种已知的三萜类化合物2-7。在其叶子中发现了一种柠檬苦素8和两种糖基黄酮9-10。通过核磁共振（NMR）和质谱（MS）分析对这些代谢产物进行了鉴定，并评估了它们对哺乳动物非洲绿猴肾（vero）、小鼠乳腺癌（4T1）、人喉癌（HEp2）和人乳腺癌（MDA-MB-231）细胞系的细胞毒性。在这些分离物中，齐墩果酸（2）表现出最高的细胞毒性，即对HEp2和4T1细胞的半数抑制浓度（IC50）分别为1.4 μM和13.3 μM。由于粗树皮提取物的细胞毒性高于分离物，因此评估了齐墩果酸（2）与五种三萜类化合物3-7在vero细胞上的相互作用。在抗疟原虫试验中，观察到其中七种代谢产物对恶性疟原虫的D6和W2菌株具有中等活性（IC50为27.1-97.1 μM），然而选择性指数较低（IC50(vero)/IC50(P. falciparum-D6)<10）。观察到的中等抗疟原虫活性可能是由于分离出的三萜类化合物具有一般细胞毒性。
