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schang1984 schang1984
wrote...
Posts: 6
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5 years ago
What is wrong with my theory:
 
Quercetin is an antioxidant. It neutralizes free radicals. While doing so this, Quercetin converts into a radical molecule. For example, it neutralizes 4 radical molecules and becomes a radical molecule with 4 radicals.

Then it sticks to DNA (covalent binding). Because there is no water present there, it stays a radical molecule.

When a cell divides, water nears this molecule, so it reacts with water causing OH radicals killing the cell.

Normal cells always repair their entire DNA before cell division, so the radical flavonoid molecule is removed. So normal cells stay unharmed.

Cancer cells divide before they have repaired their entire DNA, so they die.

So it's actually a bomb.

A flavonoid molecule is like a bomb that explodes if it's not removed before a cell tries to divide. Cancer cells that divide before reparation die; this happens because the bomb wasn't removed, so it explodes when the cell tries to divide. Normal cells that divide after reparation remove the bomb, so they live.

Cancer cells that do completely repair their DNA before cell division aren't cancer cells anymore (they are normal cells) because they have to wait a long time before cell division.

Normal cells that did not completely repair their DNA before cell division can pass a mutation down to daughter cells.

So flavonoids kill only cancer cells but not normal cells.

It's like this:

Normal cell -> completely repaired -> flavonoid bomb removed -> cell divides normally.

Cancer cell -> not completely repaired -> flavonoid bomb detonates -> cell killed while it was dividing.

Cancer cell that completely repairs = normal cell.

Copyright © 2007-2019 Steven Chang. All Rights Reserved.
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wrote...
Educator
5 years ago
Copyright © 2007-2019 Steven Chang. All Rights Reserved.

I get the impression this is a spam topic.

Where are you writing from schang1984?
schang1984 Author
wrote...
5 years ago
Why?
wrote...
Educator
5 years ago Edited: 5 years ago, bio_man
Why?

Because I noticed the exact same topic word-for-word was discussed in another forum.

I'll share my suggestions with you if you can answer where you're writing from
schang1984 Author
wrote...
5 years ago
Netherlands
wrote...
Educator
5 years ago Edited: 5 years ago, bio_man
Hi again

Quercetin is an antioxidant. It neutralizes free radicals. While doing so this, Quercetin converts into a radical molecule. For example, it neutralizes 4 radical molecules and becomes a radical molecule with 4 radicals.

Just after reading the first paragraph, the chemistry behind this is confusing. I don't think antioxidants turn into radicals themselves after donating an electron. Could you back that up? Wait, am I reading this correctly?
schang1984 Author
wrote...
5 years ago
According to this article:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2927345/

"Antioxidants may be molecules that can neutralize free radicals by accepting or donating electron(s) to eliminate the unpaired condition of the radical. The antioxidant molecules may directly react with the reactive radicals and destroy them, while they may become new free radicals which are less active, longer-lived and less dangerous than those radicals they have neutralized. They may be neutralized by other antioxidants or other mechanisms to terminate their radical status. For example, many antioxidants have aromatic ring structures and are able to delocalize the unpaired electron (Fig. 1). Vitamin C (AscH−) in the aqueous phase and vitamin E (TOH) in the lipid phase will directly react with or neutralize hydroxyl, alkoxyl and lipid peroxyl (ROO▪) radicals and form H2O, alcohol and lipid hydroperoxides, respectively. Vitamin E itself becomes a phenyl radical and vitamin C turns to a very stable radical (Asc−•), due to its delocalized structure (Fig. 2A and B). Furthermore, vitamin C can also neutralize the radical form of other antioxidants such as glutathione radical and vitamin E radical, and regenerate these antioxidants (Fig. 2C). "
wrote...
Educator
5 years ago
Thanks for the source! According to the source, depending on the chemistry of the antioxidant, it may become "radicalized" itself after reacting with a free radical. Does quercetin act this way, and if so can you provide a source that suggests that? The reason I'm stuck on this is because if you can't provide definitely evidence, then the rest of the spiel is a mere speculation.
schang1984 Author
wrote...
5 years ago
Here, take a look at this:

https://www.researchgate.net/figure/Structures-of-four-possible-tautomeric-forms-of-quercetin-quinone-oxidation-products-of_fig4_265189408

https://www.researchgate.net/publication/265189408_In_situ_Spectroelectrochemical_Study_of_Quercetin_Oxidation_and_Complexation_with_Metal_Ions_in_Acidic_Solutions

wrote...
Educator
5 years ago
Neither of these sources suggest that! The first one provides evidence that it is an antioxidant, the second discusses its interaction with iron ions.

Highlight the part that says that
schang1984 Author
wrote...
5 years ago Edited: 5 years ago, schang1984
How about:

Figure 2 shows the progression of spectral change of
quercetin when the oxidation potential of 0.5 V was applied.
Full oxidation took rather long time because of high solution
resistance due to the thin layer configuration. The appear-
ance of two isosbestic points at 284 and 331 nm confirms
that only two quercetin species are present. Quercetin has
two characteristic peaks at 267 and 375 nm that are due to π→π
* transitions at rings A and B, respectively. Upon
oxidation, these peaks begin to decrease and another peak at
301 nm appears. This has been recognized as quercetin
quinone (QQ). QQ can take four tautomeric forms that are
responsible for the absorption at 301 nm (Fig. 3). It is not
certain at the moment which form of QQ is a main contri-
butor.

?
wrote...
Educator
5 years ago Edited: 5 years ago, bio_man
@ schang1984

Do you have time to read up on some articles?

1) https://www.ncbi.nlm.nih.gov/pubmed/18417116 (do you have free access to this?)
2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575931/pdf/bcp0075-0637.pdf

According to these, quercetin may have prooxidant, rather than antioxidant, properties. In the process of antioxidant activities, quercetin oxidizes into various oxidation products, including semiquinone radicals and quinones.

Furthermore, according to the summary found here, the main pathway involving quercetin is the Nrf2-ARE Pathway.

Apologies for the late reply
wrote...
Staff Member
5 years ago Edited: 5 years ago, duddy
Hey all … I've been following along silently here and i've been doing some reading on my own. Quite honestly before this thread I had never heard of quercetin, nor had I ever read about it in literature. I think its quite fascinating.

 From my perspective, there are several mistakes with your theory. The first being there's no proof of anything you've mentioned. What we do know from literature is that quercetin has been shown to inhibit ROS (reactive oxygen species) found within the cell (and only specific types of cells might I add). This in turn activates an enzyme known as Nrf-2, which activates genes in the host cell's DNA (found within the nucleus), which then go on to produce enzymes and antioxidant proteins (https://ars.els-cdn.com/content/image/1-s2.0-S0278691518304368-fx1_lrg.jpg - an illustration for you). Something else that I found interesting can be located here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141509. The author states "quercetin was 10 folds more potent than cyanidin in inhibition of lipopolysaccharide (LPS)-induced NO production as well as stimulation of Nrf2-induced heme-oxygenase-1 (HO-1) protein expression." So quercetin works not directly, but indirectly as an antioxidant.


Hope my 2 cents helped

https://www.sciencedirect.com/science/article/pii/S0278691518304368
- Master of Science in Biology
- Bachelor of Science
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