Ezzat Shahira M, Salama Maha M, Mahrous Engy A, Maes Louis, Pan Cheol-Ho, Abdel-Sattar Essam
a Faculty of Pharmacy, Department of Pharmacognosy , Cairo University , Cairo , Egypt.
b Laboratory for Microbiology, Parasitology and Hygiene (LMPH) , Antwerp University , Antwerp , Belgium.
Nat Prod Res. 2017 Mar;31(6):676-680. doi: 10.1080/14786419.2016.1180604. Epub 2016 May 6.
The bioactive petroleum ether fraction of Verbesina encelioides, previously studied by the authors, was chosen for the isolation of antiprotozoal metabolites. Pseudotaraxasterol-3β-acetate (1), benzyl 2,6-dimethoxy benzoate (2), 16β-hydroxy-pseudotaraxasterol-3β-palmitate (3) and pseudotaraxasterol (4), in addition to β-sitosterol glucoside (5) and β-sitosterol galactoside (6) were isolated and identified based on one-dimensional and two-dimensional spectral analysis. This is the first report describing (3) and (6) in genus Verbesina. The isolated compounds were tested in vitro against Plasmodium falciparum, Trypanosoma brucei, Trypanosoma cruzi and Leishmania infantum. Cytotoxicity was evaluated on MRC-5 cells. Compound 1 showed moderate to weak activity against L. infantum T. brucei and P. falciparum and was inactive against T. cruzi. Compound 3 showed moderate activity against L. infantum, compound 4 revealed weak activity against T. cruzi, while 5 and 6 were inactive against all tested protozoa. All compounds were non-cytotoxic. The isolated constituents showed less antiprotozoal activity than the crude fraction.
作者之前研究过的黄顶菊生物活性石油醚馏分被选用于分离抗原生动物代谢物。基于一维和二维光谱分析，分离并鉴定出了乙酸假蒲公英甾醇-3β-酯（1）、2,6-二甲氧基苯甲酸苄酯（2）、16β-羟基-假蒲公英甾醇-3β-棕榈酸酯（3）和假蒲公英甾醇（4），此外还有β-谷甾醇葡萄糖苷（5）和β-谷甾醇半乳糖苷（6）。这是首次报道在黄顶菊属中发现（3）和（6）。对分离出的化合物进行了体外抗恶性疟原虫、布氏锥虫、克氏锥虫和婴儿利什曼原虫的测试。在MRC-5细胞上评估了细胞毒性。化合物1对婴儿利什曼原虫、布氏锥虫和恶性疟原虫表现出中度至弱活性，对克氏锥虫无活性。化合物3对婴儿利什曼原虫表现出中度活性，化合物4对克氏锥虫显示出弱活性，而5和6对所有测试的原生动物均无活性。所有化合物均无细胞毒性。分离出的成分显示出比粗馏分更低的抗原生动物活性。
