Abstract

The Nigerian and South African varieties of Siphonochilus aethiopicus were examined for their phytochemical constituents. The ethyl acetate extract of the rhizomes of the South African variety yielded a novel diarylheptanoid, 2,3-diacetoxy-7-(3′′,4′′-dihydroxy-5′′-methoxyphenyl)-1-(4′-hydroxy-3′-methoxyphenyl)-5-heptene and the flavonoid 3,7-dimethoxyquercetin. From the hexane extract of the Nigerian variety, siphonochilone and another flavonoid, 3,4′,7-trimethylkaempferol were isolated. The isolated compounds were characterised by NMR spectroscopic techniques and mass spectrometry. The diarylheptanoid was then assayed for antiplasmodial activity in vitro using a Plasmodium falciparum growth inhibition assay. At the concentrations tested, the compound inhibited parasite growth by 69 − 74%, without producing cytotoxic or significant haemolytic effects. The antiplasmodial activity of the compound is likely mediated by direct mechanism(s) in erythrocytic – stage parasites.

摘要

检查了尼日利亚和南非品种的Siphonochilus aethiopicus的植物化学成分。南非品种根茎的乙酸乙酯提取物产生了一种新型的二芳基庚烷，2,3-二乙酰氧基-7-(3'',4''-dihydroxy-5''-甲氧基苯基)-1-(4'-羟基-3'-甲氧基苯基)-5-庚烯和黄酮类化合物 3,7-二甲氧基槲皮素。从尼日利亚品种的己烷提取物中分离出虹吸虫和另一种黄酮类化合物 3,4',7-三甲基山奈酚。分离的化合物通过核磁共振光谱技术和质谱进行表征。然后使用恶性疟原虫在体外测定二芳基庚烷的抗疟原虫活性生长抑制试验。在测试的浓度下，该化合物抑制了 69 - 74% 的寄生虫生长，而不会产生细胞毒性或显着的溶血作用。该化合物的抗疟原虫活性可能由红细胞期寄生虫的直接机制介导。