Dear Reid,

I usually see works that uses the DPPH antioxidant assay. If I'm not wrong, this test is based on spectrophotometric measurements trough the color changes of DPPH when reduced.

I guess these two articles attached can help.

Best regards and hope that helps!

Article DPPH antioxidant assay revisited

Article Antioxidant activity by DPPH assay of potential solutions to...

We have used ABTS and DPPH. Both work, but have different "preferences" for radical types, so the results may differ depending on the situation. Depending on what you are trying to demonstrate, maybe it is best to use both (unless you have just a simple system with a low variability in radicals and antioxidants used). The comparison and contrasts between the results are interesting for the discussion section of the paper!

DPPH and FRAP are good and easy to perform methods

Dear you cannot ascertain antioxidant potential of and sample with one method. To evaluate the antioxidant potential of any sample you have to use different method viz. DPPH, FRAP, ABTS, Mo reducing assay, NO scavenging assay and Bita-carotenoid linoleic acid assay. Because every method hove its own importance. also keep one thing in your mind that method like DPPH, FRAP, Mo reducing assay have not  any biological relevance. where as NO scavenging assay, Bita-carotenoid linoleic acid assay, H2O2 reducing assay have biological relevance. 

You can try photochemiluminiscent based methods which are rapid, sensitive and gives reproducible results.

See the attached article.

All the best.

I also recommend  the DPPH and FRAP methods viro analysis.

DPPH assay is a simple and easy experiment

so, just try it firstly

DPPH and FRAP are good methods

Basically it depends on what/which free radical you want to scavenge.

As DPPH is used for any free radical assay, FRAP is used only for Ferrous ions conversion, and there are other assay too... like H2O2 assay, hydroxyl radical scavenging assay, Superoxide radical scavenging assay....

Firstly you should go for DPPH assay then find the main responsible free radicals in apoptosis and go for that particular assay

Hello sir

You can do DPPH (free radical scavenging ), ABTS and also NO scavenging to check antioxidant properties of samples. In addition you can also perform reducing power assay, lipid peroxidation inhibition and metal ion chelating assay.

Sir, do you work with bacterial cell. I would like to know how can i check the effect of a phytochemical on the growth pattern of bacterial cells. And how can i perform protein leakage in bacterial strains.

Uma Kant Sharma, you can try colony forming unit assays to quantify bacterial viability--the precise protocol you use will depend on your bacterial species.  There are also protocols that use PI in flow cytometry of bacteria as well.  I am not sure about protein leakage.

Dear,

You can also read my paper on antioxidant activity.

Yes, please just try it firstly. There are many reports use this DPPH in vitro system including me.

Thanks everyone, I've read most of your papers and they were very helpful of course.  I have already gotten the DPPH to work using NAC as a control, with an EC50 of about 78uM, with activity beginning around 10uM.  That seems like a relatively high concentration of NAC required for scavenging.  Can I anticipate that, intracellularly, NAC is not scavenging until the concentrations that I found in my DPPH assay?  Also, am I ignorant in assuming that antioxidants scavenge at more pharmacological doses (ie the micromolar range)?

Anyway, I am going to do DPPH assays using my phenolic compounds.  And, I hope to try NO and H2O2 scavenging tests as well, and RT-PCR to detect iNOS mRNA levels.  If anyone has any lab-protocols I'd love to talk a look!

Thanks again for all of your help everyone!