Optimized enzymatic colorimetric assay for determination of hydrogenperoxide (H2O2) scavenging activity of plantextracts

摘要

class="kwd-title">Method name: Enzymatic colorimetric assay for H2O2 scavenging activity class="kwd-title">Keywords: Colorimetric assay, Hydrogen peroxide, Scavenging activity, Plant extracts class="head no_bottom_margin" id="idm140166251518928title">AbstractThe classical method to determine hydrogen peroxide (H2O2) scavenging activity of plant extracts is evaluated by measuring the disappearance of H2O2 at a wavelength of 230 nm. Since this method suffers from the interference of phenolics having strong absorption in the UV region, a simple and rapid colorimetric assay was developed where plant extracts are introduced to H2O2, phenol and 4-aminoantipyrine reaction system in the presence of horseradish peroxidase (HRP). This reaction yields a quinoneimine chromogen which can be measured at 504 nm. Decrease in the colour intensity reflects the H2O2 scavenged by the plant material. class="first-line-outdent">

• Optimum conditions determined for this assay were30 min reaction time, 37 °C,pH 7, enzyme concentration of 1 U/ml andH2O2 concentration of0.7 mM. The limit of detection (LOD) and limitof quantitation (LOQ) were 136 μM and 411 μM, respectively.

• Half maximal effective concentration required toscavenge 50% of H2O2 in the system(EC50 value) calculated for several plantextracts and standard antioxidants resulted in coefficient ofvariance (CV%) of the EC50 values less than 3.0%and correlation coefficient values(R²) > 0.95 for all dose response curvesobtained.

• This method is convenient and very precise whichis suitable for the rapid quantification ofH₂O₂ scavenging ability ofstandard antioxidants and natural antioxidants present in plantextracts.