Synergy and Mode of Action of Ceftazidime plus Quercetin or Luteolin on Streptococcus pyogenes

Figure 3

The presence of 260 nm absorbing the material in the supernatants of S. pyogenes DMST 30653 treated with luteolin, quercetin, and ceftazidime either alone or in combination. Con = control (drugs free); Lut (64) = 64 μg mL⁻¹ luteolin; Que (64) = 64 μg mL⁻¹ quercetin; Cef (0.25) = 0.25 μg mL⁻¹ ceftazidime; Cef (0.09) + Lut (12) = ceftazidime 0.09 μg mL⁻¹ plus luteolin 12 μg mL⁻¹; Cef (0.09) + Que (3) = ceftazidime 0.09 μg mL⁻¹ plus quercetin 3 μg mL⁻¹; Nis (0.5) = 0.5 μg mL⁻¹. Nisin at 0.5 μg mL⁻¹ was used as positive control, and untreated cells were used as negative control. The study was operated in three experiments, and all graphs are shown as mean ± SEM. Means sharing the same superscript are not significantly different from each other (Scheffe’s, ).