Fu Yao-Wu, Zhang Qi-Zhong, Xu De-Hai, Wang Bin, Liang Jing-Han, Lin De-Jie
Institute of Hydrobiology, Jinan University, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering Ministry of Education, Guangzhou 510632, PR China.
Dis Aquat Organ. 2015 Nov 17;117(1):13-20. doi: 10.3354/dao02925.
Infection by Ichthyophthirius multifiliis, a ciliated protozoan parasite, results in high fish mortality and causes severe economic losses in aquaculture. To find new, efficient anti-I. multifiliis agents, cynatratoside-C was isolated from Cynanchum atratum by bioassay-guided fractionation in a previous study. The present study investigated the anti-theront activity, determined the toxicity of cynatratoside-C to grass carp Ctenopharyngodon idellus and mammalian blood cells, and evaluated the protection of cynatratoside-C against I. multifiliis theront infection in grass carp. Results showed that all theronts were killed by 0.25 mg l-1 of cynatratoside-C in 186.7 ± 5.8 min. Cynatratoside-C at 0.25 mg l-1 was effective in treating infected grass carp and protecting naive fish from I. multifiliis infestation. The 96 h median lethal concentration (LC50) of cynatratoside-C to grass carp and 4 h median effective concentration (EC50) of cynatratoside-C to theront were 46.8 and 0.088 mg l-1, respectively. In addition, the hemolysis assay demonstrated that cynatratoside-C had no cytotoxicity to rabbit red blood cells. Therefore, cynatratoside-C could be a safe and effective potential parasiticide for controlling I. multifiliis.
由纤毛虫寄生虫多子小瓜虫感染导致鱼类高死亡率，并给水产养殖业造成严重经济损失。为寻找新型高效的抗多子小瓜虫药物，前期研究通过生物活性追踪分离法从白薇中分离得到了白薇苷C。本研究考察了白薇苷C对多子小瓜虫幼虫的活性，测定了其对草鱼和哺乳动物血细胞的毒性，并评估了白薇苷C对草鱼抵御多子小瓜虫幼虫感染的保护作用。结果显示，0.25 mg l-1的白薇苷C在186.7 ± 5.8分钟内可杀死所有幼虫。0.25 mg l-1的白薇苷C可有效治疗受感染的草鱼，并保护未感染的草鱼免受多子小瓜虫侵害。白薇苷C对草鱼的96小时半数致死浓度（LC50）和对幼虫的4小时半数有效浓度（EC50）分别为46.8和0.088 mg l-1。此外，溶血试验表明白薇苷C对兔红细胞无细胞毒性。因此，白薇苷C可能是一种安全有效的控制多子小瓜虫的潜在杀虫剂。
