Dégbé Mlatovi, Debierre-Grockiego Françoise, Tété-Bénissan Amivi, Débare Héloïse, Aklikokou Kodjo, Dimier-Poisson Isabelle, Gbeassor Messanvi
Laboratoire de Physiologie et de Pharmacologie des Substances Naturelles, Faculté des Sciences, Université de Lomé, B.P. 1515, Lomé 01, Togo.
ISP, INRA, Université Tours, 37380 Nouzilly, France.
Parasite. 2018;25:11. doi: 10.1051/parasite/2018014. Epub 2018 Mar 13.
Tectona grandis (teak) and Vernonia amygdalina (bitter leaf) are plants used in traditional medicine in West Africa. In this study, we tested ethanolic and hydro-ethanolic extracts of bark and leaves of T. grandis and ethanolic extract of leaves of V. amygdalina for their inhibitory effect on Toxoplasma gondii, a protozoan parasite responsible for toxoplasmosis. Ethanolic extract of V. amygdalina leaves had proportional contents of phenols, tannins, flavonoids, and polysaccharides. This extract presented the highest efficacy against T. gondii, the lowest cytotoxicity to mammalian cells, but moderate anti-oxidant activity compared to other plant extracts. Ethanolic extract of T. grandis bark also had elevated anti-T. gondii activity, low cytotoxicity on mammalian cells, and one of the highest anti-oxidant activities. However, the phytochemical content of this extract was not very different from the hydro-ethanolic extract, which had no anti-T. gondii activity. In addition, ethanolic extract of V. amygdalina leaves, but not of T. grandis bark, significantly increased the production of TNF-α and NO by antigen-presenting cells. Both extracts had the tendency to decrease expression of major histocompatibility complex molecules at the surface of antigen-presenting cells, while they did not modulate the percentage of apoptotic cells. A study of signalling pathways would help to determine the mechanisms of action of these plant extracts.
柚木（Tectona grandis）和扁桃斑鸠菊（Vernonia amygdalina）（苦叶）是西非传统医学中使用的植物。在本研究中，我们测试了柚木树皮和树叶的乙醇提取物及水-乙醇提取物，以及扁桃斑鸠菊树叶的乙醇提取物对刚地弓形虫的抑制作用，刚地弓形虫是一种导致弓形虫病的原生动物寄生虫。扁桃斑鸠菊树叶的乙醇提取物含有比例适当的酚类、单宁、黄酮类化合物和多糖。该提取物对刚地弓形虫的疗效最高，对哺乳动物细胞的细胞毒性最低，但与其他植物提取物相比，抗氧化活性适中。柚木树皮的乙醇提取物对刚地弓形虫也有较高的活性，对哺乳动物细胞的细胞毒性较低，且具有最高抗氧化活性之一。然而，该提取物的植物化学成分与没有抗刚地弓形虫活性的水-乙醇提取物没有太大差异。此外，扁桃斑鸠菊树叶的乙醇提取物，而非柚木树皮的乙醇提取物，能显著增加抗原呈递细胞产生的肿瘤坏死因子-α和一氧化氮。两种提取物都有降低抗原呈递细胞表面主要组织相容性复合体分子表达的趋势，同时它们不会调节凋亡细胞的百分比。对信号通路的研究将有助于确定这些植物提取物的作用机制。
