Abstract：
This study assessed the in vitro anthelmintic activity of ethyl acetate extract (Cn-EtOAc) and its bioactive fractions (CnR3 and CnR5) obtained from Chamaecrista nictitans aerial parts against two Haemonchus contortus (Hc) isolates, one resistant (strain HcIVM-R) and another susceptible (strain HcIVM-S) to ivermectin. Ferulic acid and p-coumaric acid were identified in the bioactive fractions; therefore, their commercial standards were also assessed. A colocalization analysis between the ferulic acid commercial standard and eggs of the HcIVM-R strain was performed using confocal laser scanning microscopy and the ImageJ program. The ovicidal effects of the Cn-EtOAc extract, bioactive fractions and commercial compounds were tested through the egg hatching inhibition (EHI) assay on H. contortus isolates HcIVM-R and HcIVM-S. The Cn-EtOAc caused 88 % and 92 % EHI at 5000 µg/mL on HcIVM-R and HcIVM-S, respectively. Fractions CnR3 and CnR5 displayed the highest ovicidal activity against HcIVM-S, with effective concentrations (EC90) of 2134 and 601 µg/mL, respectively. Meanwhile, the commercial standards ferulic acid and p-coumaric acid also resulted in higher effectiveness on the same strain, with EC90 of 57.5 and 51.1 µg/mL. A colocalization analysis of ferulic acid and eggs of HcIVM-R revealed that this compound is localized to the cuticle surface of the embryo inside the egg parasite. The results demonstrated that both ferulic and p-coumaric acids interrupt the egg-hatching processes of the two Hc isolates. Both phenolic acids isolated from C. nictitans and commercial standards exhibited the best anthelmintic effect on HcIVM-S. These findings indicate that the phenolic acids were less effective in egg hatch inhibiting on the HcIVM-R strain compared to the HcIVM-S strain.
摘要：
这项研究评估了从Chamaecrista烟草碱地上部分获得的乙酸乙酯提取物（Cn-EtOAc）及其生物活性级分（CnR3和CnR5）对两种hemonchuscontortus（Hc）分离物的体外驱虫活性，一种对伊维菌素具有抗性（HcIVM-R菌株）和另一种易感（HcIVM-S菌株）。在生物活性组分中鉴定了阿魏酸和对香豆酸；因此，他们的商业标准也进行了评估。使用共聚焦激光扫描显微镜和ImageJ程序进行阿魏酸商业标准品与HcIVM-R菌株的卵之间的共定位分析。Cn-EtOAc提取物的杀卵作用，通过对H.contortus分离株HcIVM-R和HcIVM-S的卵孵化抑制（EHI）测定法测试了生物活性级分和商业化合物。Cn-EtOAc在5000μg/mL时对HcIVM-R和HcIVM-S引起88%和92%的EHI，分别。级分CnR3和CnR5对HcIVM-S显示出最高的杀卵活性，有效浓度（EC90）为2134和601µg/mL，分别。同时,商业标准阿魏酸和对香豆酸也导致对同一菌株更高的效力，EC90为57.5和51.1µg/mL。对阿魏酸和HcIVM-R卵的共定位分析表明，该化合物定位于卵寄生虫内部胚胎的表皮表面。结果表明，阿魏酸和对香豆酸都会中断两种Hc分离株的卵孵化过程。从C.nictitans和商业标准品分离的酚酸对HcIVM-S表现出最佳的驱虫效果。这些发现表明，与HcIVM-S菌株相比，酚酸对HcIVM-R菌株的卵孵化抑制效果较差。
