Fu YaoWu, Zhang QiZhong, Xu De-Hai, Xia Huan, Cai XinXing, Wang Bin, Liang Jinghan
Institute of Hydrobiology, Jinan University, Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering Ministry of Education, Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institutes, Guangzhou 510632, PR China.
Dis Aquat Organ. 2014 Feb 19;108(2):129-36. doi: 10.3354/dao02708.
Ichthyophthirius multifiliis (Ich), an important fish parasite, can cause significant losses in aquaculture. To find efficacious drugs to control Ich, the root bark of white mulberry Morus alba was evaluated for its antiprotozoal activity. Bark was powdered and extracted with 1 of 5 organic solvents: petroleum ether, chloroform, ethyl acetate, acetone, or methanol. The extracts were concentrated, dissolved in 0.1% (v/v) DMSO, and used for anti-Ich trials. Acetone and ethyl acetate extracts significantly reduced the survival of Ich tomonts and theronts. In vitro, acetone extract at 25 mg l-1 killed all non-encysted tomonts, at 50 mg l-1 eradicated all encysted tomonts, and at 8 mg l-1 caused mortality of all theronts. Ethyl acetate extract at 50 mg l-1 eliminated all non-encysted tomonts, at 100 mg l-1 killed all encysted tomonts and terminated tomont reproduction, and at 8 mg l-1 killed all theronts. Low concentrations (2 and 4 mg l-1) of acetone and ethyl acetate extracts could not kill all theronts after 4 h exposure, but a significant decrease in theront infectivity was observed following 30 min of pretreatment with the extracts. The 96 h LC(50) values of acetone and ethyl acetate extracts to grass carp were 79.46 and 361.05 mg l-1, i.e. much higher than effective doses for killing Ich theronts (8 mg l-1 for both extracts) and non-encysted tomonts (12.5 and 25 mg l-1, respectively). Thus M. alba extract may be a potential new, safe, and efficacious drug to control Ich.
多子小瓜虫（Ichthyophthirius multifiliis，简称Ich）是一种重要的鱼类寄生虫，会给水产养殖业造成重大损失。为了找到控制小瓜虫的有效药物，对白桑（Morus alba）的根皮进行了抗原生动物活性评估。将根皮磨成粉末，并用5种有机溶剂之一进行提取：石油醚、氯仿、乙酸乙酯、丙酮或甲醇。提取物浓缩后，溶解于0.1%（v/v）的二甲基亚砜（DMSO）中，用于小瓜虫防治试验。丙酮提取物和乙酸乙酯提取物显著降低了小瓜虫包囊幼虫和游动幼虫的存活率。在体外，25 mg l-1的丙酮提取物可杀死所有未包囊的包囊幼虫，50 mg l-1可根除所有包囊的包囊幼虫，8 mg l-1可导致所有游动幼虫死亡。50 mg l-1的乙酸乙酯提取物可消除所有未包囊的包囊幼虫，100 mg l-1可杀死所有包囊的包囊幼虫并终止包囊幼虫繁殖，8 mg l-1可杀死所有游动幼虫。丙酮提取物和乙酸乙酯提取物的低浓度（2和4 mg l-1）在暴露4小时后不能杀死所有游动幼虫，但在用提取物预处理30分钟后，观察到游动幼虫的感染力显著下降。丙酮提取物和乙酸乙酯提取物对草鱼的96小时半数致死浓度（LC(50)）值分别为79.46和361.05 mg l-1，即远高于杀死小瓜虫游动幼虫（两种提取物均为8 mg l-1）和未包囊包囊幼虫（分别为12.5和25 mg l-1）的有效剂量。因此，白桑提取物可能是一种潜在的新型、安全且有效的控制小瓜虫的药物。
