Post Graduation Program in Bioactive Natural and Synthetic Products, Federal University of Paraíba, João Pessoa 58051-900, PB, Brazil.
Biotechnology Center, Federal University of Paraíba, João Pessoa 58051-900, PB, Brazil.
Molecules. 2020 Jul 1;25(13):3015. doi: 10.3390/molecules25133015.
Viral diseases transmitted by the female L. are considered a major public health problem. The aerial parts of K. Schum (Sterculiaceae) have demonstrated potential insecticidal and larvicidal activity against this vector. The objective of this research was to investigate the mechanisms of action involved in the larvicidal activity of this species. The cytotoxicity activity of fractions and compounds of crude ethanolic extract of the aerial parts of this species was assessed by using fluorescence microscopy and propidium iodide staining. In addition, the production of nitric oxide (NO) and hemocyte recruitment were checked after different periods of exposure. The fluorescence microscopy revealed an increasing in larvae cell necrosis for the dichloromethane fraction, 7,4'-di--methyl-8--sulphate flavone and hexane fraction (15.4, 11.0, and 7.0%, respectively). The tiliroside did not show necrotic cells, which showed the same result as that seen in the negative control. The NO concentration in hemolymph after 24 h exposure was significantly greater for the dichloromethane fraction and the 7,4'-di--methyl-8--sulphate flavone (123.8 and 56.2 µM, respectively) when compared to the hexane fraction and tiliroside (10.8 and 8.3 µM, respectively). The presence of plasmocytes only in the dichloromethane fraction and 7,4'-di--methyl-8--sulphate flavone treatments suggest that these would be the hemocytes responsible for the highest NO production, acting as a defense agent. Our results showed that the larvicidal activity developed by compounds is related to its hemocyte necrotizing activity and alteration in NO production.
经雌性 L. 传播的病毒疾病被认为是一个主要的公共卫生问题。K. Schum（锦葵科）的地上部分已显示出对这种媒介具有潜在的杀虫和杀幼虫活性。本研究的目的是研究该物种杀幼虫活性涉及的作用机制。使用荧光显微镜和碘化丙啶染色评估该物种粗乙醇提取物的馏分和化合物的细胞毒性活性。此外，在不同暴露期后检查一氧化氮（NO）的产生和血淋巴细胞募集。荧光显微镜显示二氯甲烷馏分、7,4'-二--甲基-8--硫酸盐黄酮和正己烷馏分（分别为 15.4%、11.0%和 7.0%）的幼虫细胞坏死率增加。tiliroside 没有显示坏死细胞，其结果与阴性对照相同。暴露 24 小时后，二氯甲烷馏分和 7,4'-二--甲基-8--硫酸盐黄酮（分别为 123.8 和 56.2 µM）的血液中 NO 浓度明显高于正己烷馏分和 tiliroside（分别为 10.8 和 8.3 µM）。只有在二氯甲烷馏分和 7,4'-二--甲基-8--硫酸盐黄酮处理中存在浆细胞，这表明这些是产生最高 NO 的血淋巴细胞，充当防御剂。我们的结果表明，化合物表现出的杀虫活性与其血淋巴细胞坏死活性和 NO 产生的改变有关。
