Electrochemical study of oxygen interaction with lapachol and its radical anions.

Cyclovoltammetric studies were performed with lapachol [2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone], in the absence and presence of oxygen, which aimed to investigate possible oxygen interaction with lapachol and its radical anion. The obtained results clearly indicate the consumption of the semiquinone anion-radicals by oxygen in an EC type reaction, generating the deprotonated form of lapachol and HOO*. The observed generation of reactive oxygen species (ROS) after electron transfer can be related to the mechanism of biological action of lapachol.