Instituto de Física, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Instituto de Patologia Tropical e Saúde Publica, Departamento de Imunologia e Patologia Geral, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Biochim Biophys Acta Biomembr. 2022 Sep 1;1864(9):183977. doi: 10.1016/j.bbamem.2022.183977. Epub 2022 May 30.
Spin label electron paramagnetic resonance (EPR) spectroscopy was used to study the mechanisms of action of ivermectin and curcumin against Leishmania (L.) amazonensis promastigotes. EPR spectra showed that treatment of the parasites with both compounds results in plasma membrane rigidity due to oxidative processes. With the IC and EPR measurements for assays using different parasite concentrations, estimations could be made for the membrane-water partition coefficient (K), and the concentration of the compound in the membrane (c) and in the aqueous phase (c), which inhibits cell growth by 50%. The K values indicated that ivermectin has a greater affinity than curcumin for the parasite membrane. Therefore, the activity of ivermectin was higher for experiments with low cell concentrations, but for concentrations greater than 1.5 × 10 parasites/mL the compounds did not show significantly different results. The c values indicated that the concentration of compound in the membrane leading to growth inhibition or membrane alteration is approximately 1 M for both ivermectin and curcumin. This high membrane concentration suggests that many ivermectin molecules per chlorine channel are needed to cause an increase in chlorine ion influx.
自旋标记电子顺磁共振（EPR）光谱学被用于研究伊维菌素和姜黄素对利什曼原虫（L.）亚马逊滋养体的作用机制。EPR 光谱表明，这两种化合物处理寄生虫会导致氧化过程引起质膜刚性。通过对使用不同寄生虫浓度的测定进行 IC 和 EPR 测量，可以估计膜-水分配系数（K），以及在膜（c）和水相（c）中抑制细胞生长 50%的化合物浓度。K 值表明伊维菌素对寄生虫膜的亲和力大于姜黄素。因此，伊维菌素的活性在细胞浓度较低的实验中更高，但浓度大于 1.5×10 个寄生虫/ml 时，两种化合物的结果没有明显差异。c 值表明，导致生长抑制或膜改变的化合物在膜中的浓度对于伊维菌素和姜黄素而言，约为 1 M。这种高膜浓度表明，每个氯通道需要许多伊维菌素分子才能引起氯离子流入的增加。
