*3.2. Anti-Oxidant Activity of the ZnNPs*

The DPPH synthetic radicals are considered relatively stable to evaluate the radical scavenging potential of nanoparticles or other compounds. The prepared ZnNPs exhibited significant free radical scavenging activity (DPPH FRSA) which ranged from 25 to 84% inhibition (Figure 6). The NaOH (RA) ZnNPs possessed the highest antioxidant activity. The order of the FRSA was NaOH (RA) > Starch (RA)/(CA) > Albumin (CA) > Cellulose (CA) > Thiourea (RA).

**Figure 6.** Comparative antioxidant potential of ZnNPs as determined through scavenging activity (%) of DPPH radicals. Different letters denote a significant difference (*p* ≤ 0.05) among six different types of ZnNPs.
