Laboratory of Veterinary Clinical Parasitology, Department of Veterinary Medicine, Federal University of Parana, UFPR. Rua dos Funcionários 1540. CEP 80.035-050, Curitiba, PR, Brazil.
Department of Pharmacology. CIENFAR, Facultad de Química, Universidad de la República, Udelar. Av. General Flores 2124. Montevideo, Uruguay.
Acta Trop. 2021 May;217:105869. doi: 10.1016/j.actatropica.2021.105869. Epub 2021 Feb 22.
Haemonchus contortus, a blood-sucking parasite of small ruminants, produces very important economic losses in the productive sector. This abomasum parasite has become resistant to most commercial drugs worldwide, and alternatives to fight this problem are urgently needed. Essential oils (EO) are a complex mixture of volatile secondary metabolites, composed mainly by terpenoids and phenolic compounds, from plants that have several pharmacological properties, including anthelmintic activity. Particularly, citrus peel is a source of cold-pressed EO, where limonene is its major component, and can be used as an additional food component for ruminants. The aim of the present work was to determine the in vitro anthelmintic activity of EO from Citrus bergamia (EOB), C. x paradisii (EOG) and limonene against the benzimidazole-susceptible Kirby isolate of H. contortus, using the egg hatch test (EHT) and the exsheathed third stage larval motility test (XLMT) using a WMicroTracker equipment. Albendazole (ABZ) and monepantel (MON) were used as positive controls. The 50% inhibitory concentrations (IC) in XLMT were 8.77 and 13.88 µg/ml for EOB and EOG respectively, after an incubation of 72 h. An interesting observation on XLMT resulted when the positive controls were tested on the same plate, but in different well of the EOB. The volatile components of the EO significantly influenced (P < 0.05) the percentage of larval motility, reducing values from 66.9 to 19.6% for ABZ, and from 72.8 to 33.7% for MON, when comparing the activity of positive controls in a control plate without EO. The in vitro anthelmintic activity of EOB and EOG shows that they could be interesting candidates for nematode control. It is still necessary additional studies against the adult stage of H. contortus in efficacy trials in infected animals to validate their anthelmintic activity.
捻转血矛线虫是反刍动物的一种吸血寄生虫，在生产领域造成了非常严重的经济损失。这种皱胃寄生虫已对全球大多数商业药物产生了抗药性，因此迫切需要寻找替代药物来解决这个问题。精油（EO）是一种复杂的挥发性次生代谢物混合物，主要由萜类化合物和酚类化合物组成，来源于具有多种药理特性的植物，包括驱虫活性。特别是，柑橘皮是冷压 EO 的来源，其中柠檬烯是其主要成分，可以作为反刍动物的额外食物成分。本研究的目的是使用 EHT 和带有 WMicroTracker 设备的 XLMT，测定来自 Citrus bergamia (EOB)、C. x paradisii (EOG) 和柠檬烯的 EO 对苯并咪唑敏感的 Kirby 分离株捻转血矛线虫的体外驱虫活性。阿苯达唑（ABZ）和莫能菌素（MON）被用作阳性对照。在 72 小时孵育后，EOB 和 EOG 在 XLMT 中的 50%抑制浓度（IC）分别为 8.77 和 13.88μg/ml。有趣的是，当在同一平板上测试阳性对照，但在 EOB 的不同孔中时，在 XLMT 中观察到了一个有趣的结果。精油的挥发性成分显著影响（P < 0.05）幼虫运动的百分比，当在不含 EO 的对照平板上比较阳性对照的活性时，ABZ 的活性降低了 66.9%至 19.6%，MON 的活性降低了 72.8%至 33.7%。EOB 和 EOG 的体外驱虫活性表明，它们可能是控制线虫的有前途的候选药物。在感染动物的疗效试验中，仍需要对捻转血矛线虫的成虫阶段进行进一步的研究，以验证其驱虫活性。
