Optimization of Pyrogallol Autoxidation Conditions and Its Application in Evaluation of Superoxide Anion Radical Scavenging Capacity for Four Antioxidants

In this study, some factors influencing pyrogallol autoxidation, including EDTA, temperature, and solvent, were systematically investigated to improve its feasibility in the evaluation of antioxidants for the first time. Subsequently, the improved pyrogallol autoxidation conditions were used to assess the superoxide anion scavenging activity (SASA) of four commonly used antioxidants, namely, ascorbic acid, rutin, catechin, and gallic acid, by both the reaction rate method and the terminated method. The results indicate that pyrogallol autoxidation could be successfully used to determine the antioxidant capacity of ascorbic acid and rutin, which correspondingly suggests the feasibility of its use to measure the superoxide anion radical scavenging activity of polysaccharides and flavonols, because these compounds have a similar basic structural unit as ascorbic acid and rutin, respectively. Unexpectedly, however, pyrogallol autoxidation cannot be used to evaluate the SASA of catechin and gallic acid, although their good antioxidant capacity was confirmed by the 1,1-diphenyl-2-picrylhydrazyl assay. Together, these results suggest the importance of noting the conditions used for pyrogallol autoxidation when assessing the SASA of targeted compounds.

Research on the Antioxidation of Polyrhachis vicina Wine

The antioxidant activity of Polyrhachis vicina wine extract was investigated: The IC50 of scavenging effect on superoxide radical generated by Pyrogallol autoxidation was 0.37 mg/mL; the maximum scavenging rate was 81.4%. The IC50 of scavenging effect on hydroxyl free radical generated by Fenton reaction was 0.66 mg/mL; the maximum scavenging rate was 91.8%. The IC50 of DPPH· scavenging effect was 0.48 mg/mL; the maximum scavenging rate was 91.4%. The results indicated that Polyrhachis vicina wine extract showed activity both in scavenging free radicals and antioxidation.

Study on the Extraction and Antioxidant Activity of Total Flavonoids from Netted Melon with Ultrasonic

The single factor and orthogonal tests were designed to study the perfect conditions of extracting total flavononids from Netted Melon and the antioxidant activity of the extract. Firstly,the best conditions of extracting total flavononids from Netted Melon by single factor and orthogonal test was:ultrasonic power was 60%(250W) ,concentration of ethanol was 90%(V/V),extraction time was 60min ,volume of ethanol was 25mL.Under these conditions,the extraction yield of flavonoids was 0.2247 mg/g,which was 88.43% of the result of soxhlet,while,the time was 25% of soxhlet,from which the work efficiency was greatly improved. Then Prussian blue, Pyrogallol autoxidation, Phenanthroline and DPPH were used to research the antioxidant activity of flavonoid. It shows that flavonoid of Netted Melon can remove DPPH and hydroxyl radical strongly, also it has reducing capacity, but its ability of oxygen radical scavenging is poor.

Study on Synthesis and Characterization of a Fluorescence Probe and its Application for Determination of Superoxide Anion Radical

A novel Schiff base, 2-(Salicylideneamino)pyridine (2-SAP) synthesized by 2-aminopyridine and salicylaldehyde was used as a fluorescence probe to determine superoxide anion radical (O2•-) in this study. The synthetic product was characterized by IR, 1H-NMR and GC-MS methods. A fluorescence quenching reaction occurs between 2-SAP and O2•-, and the fluorescence intensity decreased significantly. The effect of pyrogallol concentration (2.0×10-5 M to1.0×10-3 M) was discussed in this study. In the range from 2.0×10-5 M to 1.0×10-4 M, relative fluorescence intensity (y) and pyrogallol concentration (x) shown a good linear relationship, y=37.801x+76.854, r=0.993. Based on this phenomenon, the O2•- generated by pyrogallol autoxidation could be determined simply with high sensitivity.