Antihelminthic action of the Anethum graveolens essential oil on Haemonchus contortus eggs and larvae

Abstract Gastrointestinal nematodes are responsible for great economic losses in sheep raising, and their control has long been carried out almost exclusively by the administration of anthelmintics, which have led to serious resistance problems. In the search for alternative control measures, phytotherapic research is highlighted. The aim of this study was to evaluate the action of Anethum graveolens (dill) essential oil on different stages of Haemonchus contortus life cycle, as well its cytotoxicity MDBK (Madin-Darby bovine kidney) cells. H. contortus larvae and eggs were obtained from infected sheep feces, and essential oil extracted from plant seeds through the Clevenger apparatus. 9.4, 4.7, 2.35, 1.17. 0.58 and 0.29 mg/mL concentrations were evaluated. The Egg Hatch Inhibition (HI), Larval Development Inhibition (LDI) and Larval Migration Inhibition (LMI) techniques were used. Thybendazole 0.025 mg/mL in HI and Levamisole 0.02 mg/mL in the LDI and LMI tests were used as positive controls, while distilled water and a Tween 80 solution were used as positive negative controls. The inhibition results obtained for the highest oil concentration were: HI 100%, LDI 98.58% and LMI 63.7%, differing (�� <0.05) from negative controls. Main A. graveolens oil components present in 95.93% of the total oil were Dihydrocarvone (39.1%), Carvone (22.24%), D-Limonene (16.84%), Apiol (10.49%) and Trans-dihydrocarvone (7.26%). Minimum A. graveolens essential oil concentrations required to inhibit 50% (IC50) of egg hatching, larval development and larval migration were 0.006 mg/mL, 2.536 mg/mL and 3.963 mg/mL, respectively. Cell viability in MDBK (Madin-Darby bovine kidney) cells, when incubated with A. graveolens essential oil, was 86% for the highest (9.4 mg/mL) and 99% for the lowest concentration (0.29 mg/mL). A. graveolens essential oil, according to the results obtained in this study, is a promising alternative in sheep gastrointestinal nematode control.

摘要 胃肠线虫给绵羊养殖业造成了巨大经济损失，长期以来其防控几乎完全依赖驱虫药的施用，这也引发了严重的抗药性问题。在寻求替代防控手段的过程中，植物疗法相关研究备受关注。本研究旨在评估莳萝（Anethum graveolens）精油对捻转血矛线虫（Haemonchus contortus）不同生命周期阶段的作用，及其对MDBK（Madin-Darby牛肾）细胞的细胞毒性。捻转血矛线虫的虫卵与幼虫采自感染绵羊的粪便，实验所用精油通过克莱文杰装置（Clevenger apparatus）从植物种子中提取得到。实验设置了9.4、4.7、2.35、1.17、0.58及0.29 mg/mL共6个浓度梯度进行评估。实验采用虫卵孵化抑制试验（Egg Hatch Inhibition, HI）、幼虫发育抑制试验（Larval Development Inhibition, LDI）及幼虫迁移抑制试验（Larval Migration Inhibition, LMI）三种方法。HI试验中以0.025 mg/mL的噻苯达唑（Thybendazole）、LDI与LMI试验中以0.02 mg/mL的左旋咪唑（Levamisole）作为阳性对照；同时以蒸馏水及吐温80（Tween 80）溶液作为阴性对照。最高精油浓度组的抑制结果如下：HI抑制率达100%，LDI抑制率为98.58%，LMI抑制率为63.7%，与阴性对照组相比差异具有统计学意义（P<0.05）。莳萝精油的主要成分占总油量的95.93%，分别为二氢香芹酮（Dihydrocarvone，39.1%）、香芹酮（Carvone，22.24%）、D-柠檬烯（D-Limonene，16.84%）、芹菜脑（Apiol，10.49%）及反式二氢香芹酮（Trans-dihydrocarvone，7.26%）。莳萝精油对虫卵孵化、幼虫发育及幼虫迁移达到50%抑制率时的半抑制浓度（IC50）分别为0.006 mg/mL、2.536 mg/mL及3.963 mg/mL。与莳萝精油共培养的MDBK细胞中，最高浓度组（9.4 mg/mL）的细胞存活率为86%，最低浓度组（0.29 mg/mL）的细胞存活率达99%。综上本研究结果表明，莳萝精油有望成为绵羊胃肠线虫防控的新型替代手段。