Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
BMC Vet Res. 2013 Feb 26;9:38. doi: 10.1186/1746-6148-9-38.
Helminthiasis is a major limitation to the livestock industry in Africa. Haemonchus contortus is the singular most important helminth responsible for major economic losses in small ruminants. The high cost of anthelmintics to small farmers, resistance to available anthelmintics and residue problems in meat and milk consumed by humans further complicates matters. The use of plants and plant extracts as a possible source of new anthelmintics has received more interest in the last decade. Our aim was not to confirm the traditional use, but rather to determine activity of extracts.Based on our past experience acetone was used as extractant. Because it is cheaper and more reproducible to evaluate the activity of plant extracts, than doing animal studies, the activity of acetone leaf extracts of thirteen plant species used traditionally in ethnoveterinary medicine in South Africa were determined using the egg hatch assay and the larval development test. Cytotoxicity of these extracts was also evaluated using the MTT cellular assay.
Extracts of three plant species i.e. Heteromorpha trifoliata, Maesa lanceolata and Leucosidea sericea had EC50 values of 0.62 mg/ml, 0.72 mg/ml and 1.08 mg/ml respectively for the egg hatch assay. Clausena anisata; (1.08 mg/ml) and Clerodendrum glabrum; (1.48 mg/ml) extracts were also active. In the larval development assay the H. trifoliata extract was the most effective with an EC50 of 0.64 mg/ml followed by L. sericea (1.27 mg/ml). The activities in the larval development test were generally lower in most plant species than the egg hatch assay. Based on the cytotoxicity results C. anisata was the least toxic with an LC50 of 0.17 mg/ml, while Cyathea dregei was the most toxic plant with an LC50 of 0.003 mg/ml. The C. anisata extract had the best selectivity index with a value of 0.10 and 0.08 for the two assays, followed by H. trifoliata and L. sericea with values of 0.07, 0.07 and 0.05, 0.04. The C. dregei extract had the worst selectivity index with a value of 0.00019 for both assays.
The result of this study indicates which species should be further investigated in depth for isolation of compounds.
寄生虫病是非洲畜牧业的主要限制因素。捻转血矛线虫是导致小反刍动物遭受重大经济损失的唯一最重要的寄生虫。小农户驱虫药物的高成本、现有驱虫药物的耐药性以及人类食用的肉类和牛奶中的残留问题，使得情况更加复杂。在过去的十年中，植物和植物提取物作为一种新驱虫剂的可能来源引起了更多的关注。我们的目的不是证实传统用途，而是确定提取物的活性。基于我们过去的经验，我们使用丙酮作为提取物。由于评估植物提取物的活性比进行动物研究更便宜、更具可重复性，因此我们使用卵孵化试验和幼虫发育试验来确定南非传统兽医民族医学中使用的 13 种植物的丙酮叶提取物的活性。还使用 MTT 细胞测定法评估了这些提取物的细胞毒性。
三种植物的提取物，即三叶苦荬菜、长叶杨梅和白珠树，对卵孵化试验的 EC50 值分别为 0.62mg/ml、0.72mg/ml 和 1.08mg/ml。罗岗榕（1.08mg/ml）和克拉伦登龙葵（1.48mg/ml）提取物也具有活性。在幼虫发育试验中，三叶苦荬菜提取物的效果最显著，EC50 值为 0.64mg/ml，其次是白珠树（1.27mg/ml）。在大多数植物物种中，幼虫发育试验的活性通常低于卵孵化试验。基于细胞毒性结果，罗岗榕提取物的毒性最低，LC50 值为 0.17mg/ml，而金毛狗蕨的毒性最高，LC50 值为 0.003mg/ml。罗岗榕提取物的选择性指数最高，两种试验的指数分别为 0.10 和 0.08，其次是三叶苦荬菜和白珠树，指数分别为 0.07、0.07 和 0.05、0.04。金毛狗蕨提取物的选择性指数最差，两种试验的指数均为 0.00019。
本研究结果表明，哪些物种应进一步深入研究以分离化合物。
