3.5.2. ABTS+• Radical Scavenging Activity

One of the most widely used organic radicals for the determination of antioxidant activity of natural products is the radical cation derived ABTS [39]. The results of ABTS+• radical scavenging activity of the *P. cretica* extract at different concentrations (25–150 μg/mL) were shown in Figure 5. It was found that the *P. cretica* extract had a scavenging activity on the ABTS+• radical in a dose dependent manner. The IC50 value of standard trolox was 30.10 μg/mL, while the IC50 value of the *P. cretica* extract was 82.92 μg/mL. A 150 μg/mL of the *P. cretica* extract exhibited 78.41 ± 2.97% inhibition. From these results, it could be stated that the *P. cretica* extract was a good ABTS+• radical scavenger.

**Figure 5.** Scavenging activity of the *P. cretica* extract obtained by optimized ultrasound-assisted extraction against ABTS+• radical compared with trolox.
