Departamento de Bioquímica, CCB, Universidade Federal de Pernambuco, Cidade Universitária, Recife, Pernambuco, Brasil.
Arch Insect Biochem Physiol. 2012 Mar;79(3):135-52. doi: 10.1002/arch.21012.
Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality.
埃及伊蚊的控制对于减少登革热至关重要。埃及伊蚊幼虫已经对有机磷杀虫剂产生了抗性，而使用天然幼虫杀虫剂可能有助于通过增加杀虫剂轮换计划中的元素来管理幼虫抗性。在这里，我们报告了辣木花提取物对埃及伊蚊 L(1)、L(2)、L(3)和 L(4)幼虫的杀幼虫活性，以及花提取物对 L(4)幼虫肠道胰蛋白酶和全幼虫乙酰胆碱酯酶的影响。此外，还研究了加热的花提取物对 L(4)幼虫的杀幼虫活性及其对幼虫肠道胰蛋白酶的影响。辣木花提取物含有一种蛋白质胰蛋白酶抑制剂（辣木花胰蛋白酶抑制剂，MoFTI）、三萜（β-香树脂醇）、固醇（β-谷甾醇）和类黄酮（山柰酚和槲皮素）。对 L(2)、L(3)和 L(4)检测到杀幼虫活性（LC(50)分别为 1.72%、1.67%和 0.92%）。花提取物抑制 L(4)肠道胰蛋白酶（MoFTI K(i) = 0.6 nM），且不影响乙酰胆碱酯酶活性。体内试验表明，用辣木花提取物处理的 L(4)肠道胰蛋白酶活性随时间（0-1,440 min）而降低，经 310 min 孵育后被强烈抑制（98.6%）；乙酰胆碱酯酶活性不受影响。热处理导致胰蛋白酶抑制剂和杀幼虫活性丧失，这支持了花提取物含有一种蛋白质胰蛋白酶抑制剂，可能是导致幼虫死亡率降低的有害影响的假说。
