Laboratory of Pharmaceutical Analysis, Faculty of Medicine and Pharmacy, University of Mons, 7000, Mons, Belgium.
Toxicon. 2023 May;227:107092. doi: 10.1016/j.toxicon.2023.107092. Epub 2023 Mar 24.
The rise and spread of resistant Plasmodium falciparum strains are responsible for an increase in therapeutic failures in many of the regions endemic with malaria. The need for new therapeutic candidates is now more urgent than ever. Animal venoms have long been considered as interesting resources to exploit in terms of potential therapeutic candidates. Among these, the cutaneous secretions of toads constitute a rich and diverse source of bioactive molecules. We focused on two different species: Bufo bufo and Incilius alvarius. The dried secretions underwent a solvent-based extraction and were submitted to a systematic bio-guided fractionation approach using preparative thin-layer chromatography. Initial crude extracts were tested in vitro for their antiplasmodial activity. Based on these results, only crude extracts displaying IC < 100 μg/mL were considered for further fractionation. All extracts and fractions, including those that did not display antiplasmodial properties, were characterized by chromatographic (LC-UV/MS) and spectrometric techniques (HRMS). Antiplasmodial activity was evaluated in vitro using a chloroquine-sensitive strain (3D7) and a resistant one (W2). Toxicity was assessed on normal human cells for the samples displaying IC < 100 μg/mL. Crude extracts from Bufo bufo secretions exhibited no appreciable antiplasmodial activities. However, the methanol and dichloromethane extracts from Incilius alvarius secretions gave IC of (34 ± 4) μg/mL and (50 ± 1) μg/mL respectively when tested on W2 strain. No significant effect was observed on 3D7. This poison would warrant further investigation in terms of its antiplasmodial potential. Following preliminary characterization, it was revealed that the fractions of interest contained mainly bufotoxins, bufagins and alkaloids.
疟原虫耐药株的出现和传播是导致许多疟疾流行地区治疗失败率上升的原因。现在比以往任何时候都更需要新的治疗候选药物。动物毒液一直被认为是有潜力的治疗候选药物的有趣来源。在这些毒液中，蟾蜍的皮肤分泌物是生物活性分子的丰富而多样的来源。我们专注于两种不同的物种：Bufo bufo 和 Incilius alvarius。干燥的分泌物经过基于溶剂的提取，并采用制备性薄层色谱法进行系统的生物导向分离。初始粗提取物在体外进行抗疟活性测试。基于这些结果，只有显示 IC < 100 μg/mL 的粗提取物才被认为适合进一步分离。所有提取物和馏分，包括那些没有显示抗疟特性的提取物，都通过色谱（LC-UV/MS）和光谱技术（HRMS）进行了表征。使用氯喹敏感株（3D7）和耐药株（W2）在体外评估抗疟活性。对显示 IC < 100 μg/mL 的样品在正常人类细胞上评估毒性。Bufo bufo 分泌物的粗提取物没有表现出明显的抗疟活性。然而，Incilius alvarius 分泌物的甲醇和二氯甲烷提取物在测试 W2 株时分别给出了 IC（34 ± 4）μg/mL 和（50 ± 1）μg/mL。在 3D7 上没有观察到显著的影响。这种毒素值得进一步研究其抗疟潜力。经过初步表征，发现有价值的馏分主要含有 Bufotoxins、Bufagins 和生物碱。
