3.6 Influence of indoxyl on intracellular redox status
To explore the influence of indoxyl on the intracellular redox status ofS. aureus , the activity level of cells was studied and analyzed during cell growth. As shown in Fig. 6a, indoxyl increased the level of intracellular peroxide, indicating that it affected the intracellular redox status. Moreover, the production of peroxides also has a very large side effect on cell activity (Cui et al., 2019). The results were also consistent with this conclusion (Fig. 3). As the main products in the tricarboxylic acid (TCA) cycle, ATP and NADH can be used to determine the growth of cells. The gradual decrease of intracellular ATP content and increase of NAD+/NADH ratio confirmed the inhibitory effect of indoxyl on the TCA cycle (Fig. 6a, c). Therefore, it could be considered that indoxyl destroyed the TCA cycle and reduced the generation of ATP and reducing power. The change in redox status promoted the generation of H2O2, which may damage cells through the oxidation of lipids, proteins and DNA.