Centro de Investigación Científica de Yucatán, Calle 43 No 130 Colonia Chuburná de Hidalgo, CP 97200 Mérida, Yucatán, Mexico.
Vet Parasitol. 2011 Jun 30;179(1-3):100-6. doi: 10.1016/j.vetpar.2011.02.019. Epub 2011 Mar 1.
The development of anthelmintic resistance has impacted on the success of conventional anthelmintics (AH) for the control of gastrointestinal nematodes in grazing/browsing sheep and goats. Medicinal plants from the traditional herbolary in Mexico may provide new candidates that can be explored as alternative sources of AHs for ruminants. This study evaluated the leaf extracts derived from Phytolacca icosandra against infective L(3) larvae and eggs from Haemonchus contortus collected from sheep. Three extracts of different polarities were obtained from the leaf plants using ethanol, n-hexane and dichloromethane as the solvents. The effectiveness of the in vitro AH activity of the plant extracts was evaluated using larval migration inhibition (LMI) and egg hatch (EHA) assays. For the LMI assays, the ethanolic extract of P. icosandra showed 55.4% inhibition of larval migration at 2mg/mL (p<0.05). The dichloromethane extract of P. icosandra showed 67.1% inhibition of migration at 3mg/mL (p<0.05) and a dose-dependent response with an LD(50) of 0.90 mg/mL. The n-hexane extract failed to show inhibition of larval migration at any concentration explored. In the EHA for the ethanol extract, the lowest concentration tested (0.15 mg/mL) resulted in inhibition of egg hatching greater than 72.6%. Therefore, the LD(50) could not be calculated for this extract. The LD(50) of the dichloromethane extract of P. icosandra was 0. 28 mg/mL. An egg hatch inhibition greater than 90% was observed with both the ethanolic and dichloromethane extracts when using a concentration of 0.90 mg/mL or higher. The n-hexane extract failed to show egg hatch inhibition at any concentration tested. The AH activity reported for P. icosandra could be attributable to the flavonoids, steroids, terpenoids, coumarins and/or saponins that were present in the ethanolic and dichloromethane extracts. A combination of more than one component may also explain the observed AH activity against the H. contortus life stages that were evaluated. In conclusion, the ethanolic and dichloromethane extracts of P. icosandra showed clear in vitro AH activity against the H. contortus eggs and the L(3) larvae. However, the hexanic extract of the plant leaves failed to show any in vitro AH activity.
抗蠕虫药物耐药性的发展影响了传统驱虫药物（AH）对放牧/啃食绵羊和山羊胃肠道线虫的控制效果。来自墨西哥传统草药学的药用植物可能提供新的候选药物，可以作为反刍动物 AH 的替代来源进行探索。本研究评估了从 Phytolacca icosandra 叶中提取的提取物对从绵羊中收集的旋毛虫感染性 L（3）幼虫和卵的作用。使用乙醇、正己烷和二氯甲烷作为溶剂从叶植物中获得三种不同极性的提取物。使用幼虫迁移抑制（LMI）和卵孵化（EHA）测定评估植物提取物的体外 AH 活性。对于 LMI 测定，2mg/mL 时 P.icosandra 的乙醇提取物显示出 55.4%的幼虫迁移抑制（p<0.05）。P.icosandra 的二氯甲烷提取物在 3mg/mL 时显示出 67.1%的迁移抑制（p<0.05），并且呈剂量依赖性反应，LD（50）为 0.90mg/mL。在任何浓度下，正己烷提取物均未显示出对幼虫迁移的抑制作用。在乙醇提取物的 EHA 中，测试的最低浓度（0.15mg/mL）导致卵孵化抑制大于 72.6%。因此，无法为此提取物计算 LD（50）。P.icosandra 的二氯甲烷提取物的 LD（50）为 0.28mg/mL。当使用 0.90mg/mL 或更高浓度时，乙醇和二氯甲烷提取物均观察到卵孵化抑制率大于 90%。在任何测试浓度下，正己烷提取物均未显示出卵孵化抑制作用。P.icosandra 报道的 AH 活性可能归因于存在于乙醇和二氯甲烷提取物中的类黄酮、类固醇、萜类、香豆素和/或皂苷。一种以上成分的组合也可能解释了对评估的旋毛虫生活阶段观察到的 AH 活性。总之，P.icosandra 的乙醇和二氯甲烷提取物对 H.contortus 卵和 L（3）幼虫表现出明显的体外 AH 活性。然而，植物叶片的正己烷提取物未显示出任何体外 AH 活性。
