Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
Exp Parasitol. 2018 Dec;195:44-53. doi: 10.1016/j.exppara.2018.10.003. Epub 2018 Oct 16.
Toxoplasmosis is a worldwide parasitic disease responsible for serious health problems to human. The currently available drugs used for toxoplasmosis treatment showed a limited efficacy and cause serious host toxicity. The in vitro screening for toxoplasmicidal activity of Araucaria heterophylla resin (AHR) extract and its major component 13-epi-cupressic acid (CUP) showed that both AHR (EC = 3.90) and CUP (EC = 3.69) have high toxoplasmicidal activity in comparison with standard cotrimoxazole (EC = 4.28). The antiprotozoal effects of AHR and CUP were investigated against acute and chronic toxoplasmosis using mice models. Two groups of Swiss albino mice were infected by RH Toxoplasma strain intraperitoneally and by Me49 strain orally. Both groups were treated with AHR and CUP in different doses. Their effects were evaluated by survival rate, peritoneal, spleen and liver parasite burdens, brain cyst burden, NO serum level and histopathological lesions. The ultrastructural changes of tachyzoites of acutely infected mice were studied using scanning electron microscopy (SEM). There is an evidence of toxoplasmicidal activity of AHR and CUP in acute and chronic experimental toxoplasmosis. In the acute model, mice treated with AHR and CUP showed prolonged survival rates, a significant decrease in the parasite density in peritoneal lavage and pathological insult in both liver and spleen compared with that of untreated ones. SEM results denote evident morphological alterations of treated tachyzoites. In chronic experimental toxoplasmosis, AHR and CUP treated groups could significantly reduce brain cyst burden by 96.05% and 98.02% respectively. This study indicates that AHR and CUP showed potent toxoplasmicidal activities experimentally and could be used as a potential natural nontoxic agent for treatment of toxoplasmosis.
弓形体病是一种全球性寄生虫病，可导致人类严重的健康问题。目前用于治疗弓形体病的药物疗效有限，且会引起严重的宿主毒性。体外筛选南洋杉树脂（AHR）提取物及其主要成分 13-表-贝壳杉烯酸（CUP）的抗弓形体活性表明，AHR（EC=3.90）和 CUP（EC=3.69）均具有比标准复方磺胺甲噁唑（EC=4.28）更高的抗弓形体活性。采用小鼠模型研究了 AHR 和 CUP 对急性和慢性弓形体病的抗原虫作用。两组瑞士白化病小鼠经腹腔感染 RH 弓形体株和经口感染 Me49 株感染，用不同剂量的 AHR 和 CUP 治疗。通过存活率、腹腔、脾脏和肝脏寄生虫负荷、脑囊虫负荷、NO 血清水平和组织病理学损伤来评估它们的作用。用扫描电子显微镜（SEM）研究了急性感染小鼠速殖子的超微结构变化。有证据表明 AHR 和 CUP 在急性和慢性实验性弓形体病中有抗弓形体活性。在急性模型中，与未治疗的小鼠相比，用 AHR 和 CUP 治疗的小鼠存活率延长，腹腔灌洗液中的寄生虫密度显著降低，肝脏和脾脏的病理损伤也降低。SEM 结果表明，治疗后的速殖子有明显的形态改变。在慢性实验性弓形体病中，AHR 和 CUP 治疗组可使脑囊虫负荷分别显著降低 96.05%和 98.02%。本研究表明，AHR 和 CUP 在实验中具有较强的抗弓形体活性，可作为治疗弓形体病的潜在天然无毒药物。
