3.5.3. NO• Radical Scavenging Activity

Despite the potential health benefits of NO• radical, its role in causing oxidative damage is becoming progressively prominent [40]. In this work, the scavenging effect of the *P. cretica* extract on NO• radical was studied. Figure 6 showed that the *P. cretica* extract within the concentration range tested (25–250 μg/mL) exhibited NO• radical scavenging activity in a dose-dependent manner. Especially, the *P. cretica* extract exhibited a maximum percentage scavenging of 82.71 ± 1.54%, which was comparable to the NO• radical scavenging activity of ascorbic acid. The IC50 value of ascorbic acid was 51.60 μg/mL, and for the *P. cretica* extract it was 89.12 μg/mL. Results indicated that *P. cretica* might serve as an excellent NO• radical scavenger due to the high level of flavonoids. It has been reported that the flavonoids are very powerful NO• radical scavengers [41].

**Figure 6.** NO• radical scavenging activity of the *P. cretica* extract obtained by optimized ultrasound-assisted compared with ascorbic acid.
