Gastrointestinal nematode infections are the main diseases in herds of small ruminants. Resistance to the main established drugs has become a worldwide problem. The purpose of this study is to obtain and evaluate the in vitro ovicidal and larvicidal activity of some 2-phenylbenzimidazole derivatives on susceptible and resistant strains of Teladorsagia circumcincta. Compounds were prepared by known procedures from substituted o-phenylenediamines and arylaldehydes or intermediate sodium 1-hydroxyphenylmethanesulfonate derivatives. Egg Hatch Test (EHT), Larval Mortality Test (LMT) and Larval Migration Inhibition Test (LMIT) were used in the initial screening of compounds at 50 μM concentration, and EC₅₀ values were determined for the most potent compounds. Cytotoxicity evaluation of compounds was conducted on human Caco-2 and HepG2 cell lines to calculate their Selectivity Indexes (SI). At 50 μM concentration, nine out of twenty-four compounds displayed more than 98% ovicidal activity on a susceptible strain, and four of them showed more than 86% on one resistant strain. The most potent ovicidal benzimidazole (BZ) 3 showed EC₅₀ = 6.30 μM, for the susceptible strain, while BZ 2 showed the lowest EC₅₀ value of 14.5 μM for the resistant strain. Docking studies of most potent compounds in a modelled Teladorsagia tubulin indicated an inverted orientation for BZ 1 in the colchicine binding site, probably due to its fair interaction with glutamic acid at codon 198, which could justify its inactivity against the resistant strain of T. circumcincta.

胃肠道线虫感染是小反刍动物群中的主要疾病。对主要已确立的药物的耐药性已成为世界性问题。本研究的目的是获得和评价某些2-苯基苯并咪唑衍生物对环柏变易感菌株的体外杀卵和杀幼虫活性。通过已知方法由取代的邻苯二胺和芳醛或中间体1-羟基苯基甲磺酸钠衍生物制备化合物。卵孵化试验（EHT），幼虫死亡率试验（LMT）和幼虫迁移抑制试验（LMIT）用于浓度为50μM和EC ₅₀的化合物的初始筛选确定最有效化合物的值。在人Caco-2和HepG2细胞系上进行了化合物的细胞毒性评估，以计算其选择性指数（SI）。在50μM浓度下，二十四个化合物中的九个对易感菌株显示出超过98％的杀卵活性，其中四个对一种抗性菌株显示出超过86％的杀卵活性。 对于易感菌株，最有效的杀卵剂苯并咪唑（BZ）3的EC ₅₀ = 6.30μM，而对于抗性菌株，BZ 2的EC ₅₀值最低，为14.5μM。在模拟的Teladorsagia微管蛋白中对大多数有效化合物的对接研究表明BZ 1的方向相反在秋水仙碱的结合位点，可能是由于它与第198位密码子的谷氨酸有公平的相互作用，这可能证明它对环柏的抗药性没有活性。