[joka]

Dear All,

I wondered whether you can help me. I have eight phytochemicals that are known to have an antioxidant capacity. I want to know their antioxidant potential based on their structures. In other words, which one would be the strongest and weakest antioxidant (and the rest in between).

Here are the compounds:

Chlorogenic acid   
Ellagic acid   
Epicatechin   
Homovanillic acid   
Isorhamnetin   
Naringenin   
Phloretin   
Veratraldehyde   

I tried to draw structures using SMILES but failed miserably so here is the link to a table (hope it's ok): http://imgur.com/l2lLYgT

So what I found is that the activity of an antioxidant is determined by:
*its reactivity as a hydrogen or electron donating agent (does it mean chlorogenic acid is the most potent?)
*the fate of the resulting antioxidant-derived radical (yyy....)
*its reactivity with other antioxidants (I don't know if this is relevant here because we're purely looking at its structure)
*the transition metal-chelating potential (again... clueless).


Thank you for your help in advance!

[Borek]

*the fate of the resulting antioxidant-derived radical (yyy....)
*its reactivity with other antioxidants (I don't know if this is relevant here because we're purely looking at its structure)
*the transition metal-chelating potential (again... clueless).

So you want to compare things not knowing how they work nor why they work, using poorly defined metrics? "Stronger" and "weaker" don't make any sense as long as you can't assign a well defined number describing antioxidative properties of each of the substances.

Even the term "antioxidant" is poorly defined - that is, it is obvious that the definition ("substance that inhibits the oxidation of other molecules") is so broad many chemicals will be classified as either antioxidants or not-antioxidants depending on whom you will ask.

I am afraid you are asking impossible (unless you are ready to accept an approximate answer - but then you have to be prepared you will get different answers depending on whom you will ask).

[joka]

That's interesting what you said. I'm not a chemist and I have to admit my knowledge is very limited.  I was looking at different properties of these compounds and came across their 'antioxidant' functions. I thought that it would be possible to say more about them based on the structure.

Thanks for your answer. At least I know now it's not that straightforward.