Leesombun Arpron, Boonmasawai Sookruetai, Nishikawa Yoshifumi
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Department of Preclinical and Applied Animal Science, Faculty of Veterinary Science, Mahidol University, 999 Phutthamonthon Sai 4 Road Salaya, Phutthamonthon, Nakhon Pathom 73170, Thailand.
Parasitol Int. 2017 Jun;66(3):219-226. doi: 10.1016/j.parint.2017.01.017. Epub 2017 Jan 27.
Neosporosis has a worldwide distribution and causes economic losses in farming, particularly by increasing the risk of abortion in cattle. This study investigated the effects of Thai piperaceae (Piper betle, P. nigrum, and P. sarmentosum) extracts on Neospora caninum infections in vitro and in vivo. In an in vitro parasite growth assay based on the green fluorescent protein (GFP) signal, P. betle was the most effective extract at inhibiting parasite growth in human foreskin fibroblast cells (IC of GFP-expressing N. caninum parasites, 22.1μg/ml). The P. betle extract, at 25μg per ml, inhibited parasite invasion into host cells. Furthermore, in two independent experiments, treating N. caninum-infected mice with the P. betle extract for 7days post-infection increased their survival. In trial one, the anti-N. caninum effects of the P. betle extract reduced the mouse clinical scores for 30days post-infection (dpi). The survival rate of the mice treated with 400mg/kg was 100% compared with 66.6% for those treated with 100mg/kg and the non-treated controls. In trial two, treating the infected mice with the P. betle extract increased their survival at 50dpi. All mice in the non-treatment group died; however, the survival rates of the 400mg/kg-treated and 100mg/kg-treated mice were 83.3% and 33.3%, respectively. Also, a trend towards a reduced parasite burden was noted in the brains of the P. betle extract-treated mice, compared with the control mice. Therefore P. betle extract has potential as a medicinal plant for treating neosporosis.
新孢子虫病在全球范围内均有分布，会给养殖业造成经济损失，尤其是会增加牛流产的风险。本研究调查了泰国胡椒科植物（蒌叶、黑胡椒和莲叶胡椒）提取物对犬新孢子虫体外和体内感染的影响。在基于绿色荧光蛋白（GFP）信号的体外寄生虫生长试验中，蒌叶提取物在抑制人包皮成纤维细胞中寄生虫生长方面最为有效（表达GFP的犬新孢子虫寄生虫的半数抑制浓度为22.1μg/ml）。每毫升25μg的蒌叶提取物可抑制寄生虫侵入宿主细胞。此外，在两项独立实验中，用蒌叶提取物在感染后7天治疗感染犬新孢子虫的小鼠可提高其存活率。在试验一中，蒌叶提取物的抗犬新孢子虫作用使感染后30天（dpi）的小鼠临床评分降低。400mg/kg治疗组小鼠的存活率为100%，而100mg/kg治疗组和未治疗对照组的存活率为66.6%。在试验二中，用蒌叶提取物治疗感染小鼠可提高其在50dpi时的存活率。未治疗组的所有小鼠均死亡；然而，400mg/kg治疗组和100mg/kg治疗组小鼠的存活率分别为83.3%和33.3%。此外，与对照小鼠相比，在蒌叶提取物治疗的小鼠大脑中发现寄生虫负荷有降低的趋势。因此，蒌叶提取物有潜力成为治疗新孢子虫病的药用植物。
