Experimental results were expressed as mean ± SD. The data were analyzed for statistical significance by Analysis of Variance.22 Data were considered significant at p < 0.05. The DPPH radical scavenging activity of silver nanoparticles PFT�� synthesized by M. pubescens was studied. The decolorization from purple DPPH radical to yellow DPPHH molecule by the sample in a dose-dependent manner with an IC50 value of 84 ± 0.25 μg/ml indicated the sample’s high radical scavenging activity which was closer to that of the standard whose IC50 value was found to be 80 ± 0.69 μg/ml as shown in Fig. 1. Superoxide anion derived from
dissolved oxygen by PMS-NADH coupling reaction reduced NBT. The decrease of absorbance at 560 nm with antioxidants indicated the consumption Selleck HKI-272 of superoxide anion in the reaction mixture. The silver nanoparticles (100 μg/ml) exhibited superoxide
radical scavenging activity of 34 ± 1.21% comparable to that of the standard which showed 43 ± 1.06% activity. Absorbance values of the sample and the standard were higher than that of control as in Fig. 2. The scavenging capacity of the silver nanoparticles from leaf extract of M. pubescens was shown in Fig. 3. At a concentration of 100 μg/ml, the silver nanoparticles showed 37 ± 2.01% hydroxyl radical scavenging activity with the standard tocopherol activity being 42 ± 2.22%. The radical scavenging capacity of the sample might be attributed to phenolic compounds in the sample with the ability to accept electrons, which could combine with free radical competitively to decrease hydroxyl radical. The presence of
chelating agents in the sample disrupted the Ferrozine-Fe2+ complex PAK6 formation. Thus the decrease in the absorbance at 562 nm indicated high levels of iron binding potential and antioxidant activity of the nanoparticles (Fig. 4). The sample of 100 μg/ml concentration possessed 56 ± 1.36% metal chelating activity with EDTA expressing 62 ± 1.78% activity. The assay was based on the reduction of Mo (VI) to Mo (V) by the sample and subsequent formation of a green phosphate-Mo (V) complex at acidic pH. The silver nanoparticles exhibited powerful antioxidant activity of 57 ± 1.65% compared to that of the standard with 69 ± 1.22% activity, in the reduction of phosphomolybdenum complex as shown in the Fig. 5. The FTC method was used to measure the peroxide levels during the initial stage of lipid peroxidation. Silver nanoparticles successfully inhibited the oxidation of linoleic acid. Low absorbance values of the sample compared to the control indicated high levels of antioxidant activity. The absorbance of the control increased till 6th day and then decreased entering into the secondary stage of lipid peroxidation. Fig. 6 detailed the absorbance values with respect to days of incubation.