Figure 3. Inhibitory effect of indoxyl on S. aureusgrowth. Influence on (a) OD600, (b) glucose consumption, (c) acetic acid production, (d) Colony–Forming Unit (CFU) at 10 h. (e, f) A comparison among the antimicrobial effects of indigo, indirubin and indoxyl at the same concentration. Influence of indigo, indirubin and indoxyl on (e) glucose consumption, (f) acetic acid production.