Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Brasil.
Toxicol Mech Methods. 2010 Sep;20(7):424-7. doi: 10.3109/15376516.2010.490968.
Paraquat is a broad-spectrum contact herbicide that has been encountered worldwide in several cases of accidental, homicidal, and suicidal poisonings. The pulmonary toxicity of this compound is related to the depletion of NADPH in the pneumocytes, which is continuously consumed by the reduction/oxidation of paraquat and reductase enzyme systems in the presence of O(2) (redox cycling). Based on this mechanism, an enzymatic-spectrophotometric method was developed for the determination of paraquat in urine samples. The velocity of NADPH consumption was monitored at 340 nm, every 10 s during 15 min. The velocity of NADPH oxidation correlated with the paraquat levels found in samples. The enzymatic-spectrophotometric method showed to be sensitive, making possible the detection of paraquat in urine samples at concentrations as low as 0.05 mg/L.
百草枯是一种广谱接触性除草剂，在世界范围内已发生多起因意外、故意和自杀摄入导致中毒的案例。该化合物的肺部毒性与肺细胞中 NADPH 的耗竭有关，在存在 O(2)（氧化还原循环）的情况下，百草枯和还原酶系统的还原/氧化会不断消耗 NADPH。基于这一机制，开发了一种用于尿液样本中百草枯检测的酶分光光度法。在 15 分钟内，每 10 秒监测 340nm 处 NADPH 的消耗速度。NADPH 氧化的速度与样品中发现的百草枯水平相关。酶分光光度法具有较高的灵敏度，可检测到尿液样本中低至 0.05mg/L 的百草枯。
