Background: Reactive oxygen species are formed through the electron transfer reactions in
the mitochondria and chloroplasts and rapidly converted to H2O2.Therefore, H2O2 as a more stable
ROS can be considered as an indicator of cellular stress and it can be used in a steady state to monitor
intracellular stress level. In this regard, the increasing use of various nanoparticles, most of which are
associated with biological systems, are essential to be studied for their possible adverse effects. We
measured the concentration of hydrogen peroxide in samples collected before and after the treatment
with silver nanoparticles by a novel method and optimized this method for the living tissue.
Methods: In this study, we evaluated the endogenous H2O2 production from Pyricularia oryzae tissue
under normal and stress conditions (such as after treatment with nanoparticles) by spectrophotometric
assay. The method used is based on instant reaction of hydrogen peroxide with vanadium pentoxide in
sulfuric acid solution, forming a peroxovanadate complex that has a maximum absorption at 454 nm.
This method was also compared with other methods.
Results: The results of this method compared with other methods in the same tissue showed that the
method is simple, inexpensive and more efficient, and the complex is stable for several hours and can
be used for a variety of H2O2 concentrations. Also, the detection range of the mentioned method
equals with high-sensitivity methods such as available commercial kits. Furthermore, this method can
also measure higher values of H2O2.
Conclusion: The optimized methods for measuring the H2O2 concentration with vanadium pentoxide
in sulfuric acid solution by the colorimetric method are simple, efficient, rapid, accurate, cost-effective
and do not have problems of other methods. The measurements using this method in Pyricularia
oryzae under oxidative stress showed that the created oxidative stress caused by the use of silver
nanoparticles increased H2O2 in fungal tissue. H2O2 is the SOD reaction product that is later decomposed
by CAT. This method is able to measure H2O2 in different ranges and under normal and stress
conditions which are indicative of antioxidant defense. Therefore, we recommend it to the researchers
in similar conditions.