National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasitology and Vector Biology of the Chinese Ministry of Health, Shanghai, 200025, China.
Guangdong Provincial Center for Disease Control and Prevention, WHO Collaborating Centre for Surveillance, Research and Training of Emerging Infectious Diseases, Guangzhou, 511430, Guangdong, China.
Parasit Vectors. 2018 May 9;11(1):291. doi: 10.1186/s13071-018-2868-7.
The snail Biomphalaria straminea is one of the intermediate hosts of Schistosoma mansoni. Biomphalaria straminea is also an invasive species, known for its strong capability on peripheral expansion, long-distance dispersal and colonization. Using molluscicides to control snail populations is an important strategy to interrupt schistosomiasis transmission and to prevent the spread of the invasive species. In this study, a series of pyridylphenylurea derivatives were synthesized as potential molluscicides. Their impact on adult snails and egg masses was evaluated. Acute toxicity to fish of the derivatives was also examined to assess their effect on non-target organisms. The preliminary mechanisms of action of the derivatives were studied by enzyme activity assays.
The representative compounds, 1-(4-chlorophenyl)-3-(pyridin-3-yl)urea (compound 8) and 1-(4-bromophenyl)-3-(pyridin-3-yl)urea (compound 9), exhibited strong molluscicidal activity against adult snails with LD values of 0.50 and 0.51 mg/l and potent inhibitory effects on snail egg hatchability with IC values of 0.05 and 0.09 mg/l. Notably, both compounds showed good target specificity with potent molluscicidal capability observed in snails, but very low toxicity to local fishes. Furthermore, the exposure of compounds 8 and 9 significantly elevated the enzyme activities of acid phosphatase and nitric oxide synthase of the snails, while no significant change was recorded in the activities of alkaline phosphatase, acetylcholine esterase and superoxide dismutase.
The results suggested that compounds 8 and 9 of pyridylphenylurea derivatives could be developed as promising molluscicide candidates for snail control.
钉螺是曼氏血吸虫的中间宿主之一。钉螺也是一种入侵物种，以其强大的周边扩张、远距离扩散和殖民能力而闻名。使用杀螺剂来控制螺种群是阻断血吸虫病传播和防止入侵物种扩散的重要策略。在这项研究中，合成了一系列吡啶基苯基脲衍生物作为潜在的杀螺剂。评估了它们对成螺和螺卵的影响。还检查了衍生物对鱼类的急性毒性，以评估它们对非目标生物的影响。通过酶活性测定研究了衍生物的初步作用机制。
代表性化合物 1-(4-氯苯基)-3-(吡啶-3-基)脲（化合物 8）和 1-(4-溴苯基)-3-(吡啶-3-基)脲（化合物 9）对成螺表现出强烈的杀螺活性，LD 值分别为 0.50 和 0.51 mg/l，对螺卵孵化具有很强的抑制作用，IC 值分别为 0.05 和 0.09 mg/l。值得注意的是，这两种化合物在螺类中表现出良好的靶标特异性，具有很强的杀螺能力，但对当地鱼类的毒性很低。此外，化合物 8 和 9 的暴露显著提高了螺类酸性磷酸酶和一氧化氮合酶的酶活性，而碱性磷酸酶、乙酰胆碱酯酶和超氧化物歧化酶的活性没有显著变化。
结果表明，吡啶基苯基脲衍生物的化合物 8 和 9 可能被开发为有前途的螺类控制杀螺剂候选物。
