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The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article review. No further edits should be made to this page.

The article was promoted 05:45, 9 March 2007.

Antioxidant

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Antioxidants are important in biology and widely-used as nutrient supplements. This article gives a comprehensive overview of the various types of antioxidants and their applications. It is 65 kb in total length, self-nomination. TimVickers 05:12, 28 February 2007 (UTC)[reply]

  • Comment I'll actually read the article tomorrow, but someone will say this, so - wikilink the access dates in the references, so people's date formatting preferences work. Nice to see this article on FAC; this is such a huge improvement over where it was when I last looked at it during the science collaboration (November?). Opabinia regalis 07:51, 28 February 2007 (UTC)[reply]
Web cite formatting done. TimVickers 16:31, 28 February 2007 (UTC)[reply]
  • Comment All web based citations need retrieval dates. LuciferMorgan 10:46, 28 February 2007 (UTC)[reply]
  • Support Well-written as usual, well referenced, comprehensive, nice use of summary style and pretty lay-accessible as far as I can see—FA quality in my opinion :) Now for the nitpicks:
    • Access dates seem to have been added, so no problem there.
    • Could stand a couple of WP:DASH and MoS:T fixes; I'll see to these later if you don't mind.
    • I'd like to see a vector version of Image:Antioxidant pathway.png. Mind if I take this on when I have time? My support's not conditional to this, in case you're wondering :D
That would be wonderful, e-mail me if you need the original.
Thank you, but I'm afraid that won't be necessary :)
    • There seems to be a hilarious bit of acronym overload in the paragraph discussing superoxide dismutases. Is it Cu/Zn SOD or CuZnSOD? I'd also change "In humans, the Cu/Zn SOD..." to "In humans, copper/zinc superoxide dismutase (Cu/Zn SOD)..."
Removed and reworded.
    • You might like to unlink those unsightly redlinks in the "Industrial uses" table, until articles are created for them (if ever, that is).
Done TimVickers 16:32, 28 February 2007 (UTC)[reply]
  • Support another fine effort from Tim. With a few suggestions...
    • The history section introduces Moreau and Dufraisse by name, but never mentions them again, and doesn't wikilink them. Given the basic level at which the lead and first few sections are written, the contextless name introduction seems odd; better to either link them or take the names out.
Names removed.
    • 'Damage to DNA leads to mutations and cancer...' - I think this might be misleading to the biologically clueless. This reads like 'mutations' and 'cancer' are two distinct events, and that both are inevitable from unrepaired DNA damage. Since not every unrepaired lesion causes a mutation and not every mutation leads to cancer, this should be reworded a bit to avoid letting people draw unwarranted conclusions.
Qualified.
    • Along the same lines, it may be worth mentioning that there are pathways in the cell for isolating and degrading highly oxidized proteins.
Added link.
    • There's plenty of images already, but maybe the structures of ascorbic acid and glutathione would be good additions?
GSH has an image, I moved it to the third section.
    • The tea image is captioned 'a rich source of antioxidants', but the table immediately above identifies it as a source of tannins, which have 'anti-nutritional effects'. Expanding the caption to clarify what other antioxidants tea contains would be helpful. I'd rather see more chemical structures and chuck the generic tea picture if it comes down to it, though. Opabinia regalis 01:44, 1 March 2007 (UTC)[reply]
Caption expanded to add link common to the table on nutritional sources in the same section. I don't want to add too many structures as these tend to cause non-chemists to stop reading! TimVickers 04:54, 1 March 2007 (UTC)[reply]
Well, they're clearly silly ;) I never like these generic little decorative images, but if a picture of a teapot gets people to keep reading... Opabinia regalis 02:30, 2 March 2007 (UTC)[reply]
  • Support I do have some small concerns, but this is a FA quality article.
    • From the lead: All plants and animals maintain complex systems of antioxidants to prevent damage by oxidation Throughout the entire article I can find no mention of plants outside of them being a source of antioxidants. At the least I feel the table in the "Metabolites" section needs to list which types of antioxidants are being used by plants. Also a reminder or two in the first sentence of the more generalized sections that we are talking in broad terms and not simply human terms would be nice. Another option is to take that word out of the lead and let the article be consistent in its scope; if however slightly misleading by omission.
Discussion on oxidative stress in photosynthesis added to "Oxidative challenge in biology" section. Info on plant SOD, GSH-metabolism and thioredoxins added.
    • In section "Measurement and levels in food": Some antioxidants such as lycopene are ascorbic acid can be destroyed by long-term storage or prolonged cooking However "lycopene" is missing from the following table; so readers don't know what product they should eat fresh and raw to obtain that antioxidant.
Expanded table to give examples. TimVickers 16:55, 1 March 2007 (UTC)[reply]
    • "Technological uses" It is clear thought the preceding text that antioxidants are obtained by eating things, taking pills, or through life processes. It is unclear how they are obtained for technological use. I would think that ease of making these compounds (i.e. cost) is a large factor affecting which particular ones are used in industry and which are not. Is there anything information worth adding along that angle? I guess this same issue can be raised for the History section. Any important developments in production worth mentioning there?
    • Part of me tends to think in the long term everything under "Health effects" should really be a summary of the daughter article Antioxidants in Medicine and everything under "Technological uses" should really be a summary of the daughter article Antioxidants in Industry. And that these two sections should be more comparable in length. However that has little to do with this article qualifying for FA, which I believe it does.--BirgitteSB 14:40, 1 March 2007 (UTC)
  • Support, naturally. Another wonderfully elegant exposition by Tim on a very important and widely known topic. Here are some things I'm not sure about, but which you might want to consider. They're rather vague suggestions, and don't temper my support:
  • I'm pretty sure that selenium counts as an antioxidant, unlike zinc; it's in those enzymes because its redox potential is indeed much stronger than that of sulfur. Diselenide bonds are far more difficult to reduce than disulfide bonds.
This is an arguable point (see antioxidant talk page) but for me selenium is no more an antioxidant than zinc or sulphur. Some of the many selenoproteins do have antioxidant functions, but the cofactor of these enzymes does not function separately from the whole.
Hmm, I read the Talk section on selenium, but I was left a little mystified by the argument? Admittedly, free selenium probably doesn't play much of a physiological role, being so low in concentration, but selenium compounds are much stronger reductants (-400 mV redox potential) than the analogous sulfur compounds; they're like "thiols on steroids", if you'll forgive the biochemically mixed metaphor. ;) I think that selenium also occurs in vivo in several places where it might serve as an antioxidant, such as in the metallothioneins. There's also glutathione triselenide, methylated selenium, selenophosphate and a few other in vivo compounds; although I don't know whether they serve any antioxidant role, it would be strange if nature did not exploit selenium's great redox potential somehow, no?
Well it does, it uses it in enzyme active sites. Not metallothioneins though, those contain normal, boring cysteine, not selenocysteine. I'll have a read about those other organoselenium compounds, but I've never heard of them being proposed as biological antioxidants. TimVickers 22:07, 2 March 2007 (UTC)[reply]
  • More discussion of the importance of terminating free-radical chain reactions, relative to mopping up non-radical oxidative species?
As I understand it, and I hope the article conveys, the antioxidant defences of the body should be seen as an interacting network. Consequently, it is very had to say that one part is more important than another.
  • Provide a centralized list of the most common oxidizing agents, and oxidizing factors in biochemistry? Perhaps make a daughter list page you could refer to? Perhaps include types of environmental factors that might provoke oxidative stress (smoking, sunburn, maybe)?
Some of this is already on the oxidative stress page, I will try to expand this daughter article a little in the future.
  • Perhaps lay more stress on the dangerous randomness of reactive oxygen species, and that the cytosol is mainly a reducing environment? More discussion of the peroxisome, etc. and biologically important oxidations, say, β-oxidation?
Radicals and metals added to "Oxidative challenge" section. Added peroxisome link and ref to catalase paragraph.
  • Mention other special cases of food antioxidants, such as those in beer and wine?
The sub-page on List of antioxidants in food should give details on this.
  • More on the isoprenoids such as lycopene as antioxidants? All those double bonds are such an inviting target. ;)
  • Metal chelators don't count as antioxidants, although they might slow oxidation by withholding a catalyzing agent, right? I think I've read in the popular press of chelators mentioned as antioxidants; perhaps clearing up that confusion is worth addressing explicitly?
Added to metabolites section, with iron-binding proteins used as example.
  • My tricksy memory is telling me that fasting has some pertinent relation to oxidative stress that might be worth mentioning here, but I can't remember what it might be. :(
Interesting, I might add this to the oxidative stress article. TimVickers 18:30, 2 March 2007 (UTC)[reply]
  • Mention modern research into plant metabolic engineering to increase tocopherols and other antioxidants? I think I've heard about that going on somewhere, you know, GM food and all that.
Good luck as always and thank you, Willow 17:57, 2 March 2007 (UTC)[reply]
  • It's well-referenced, which must have been a bunch of work to do. However, I oppose because the image of fruits and vegetables seems random and uninformative. Half a sentence could have given the same information, as the caption demonstrates. I'll go so far as to suggest that the article would be better off without a picture; however, for it to be an FA, it probably will need an informative image up top. Second, the body feels choppy. The history is too brief for my liking, otherwise it's fine until the metabolites section, where things get a bit technical and text-heavy. My suggestion would be for some of those sections to have "signpost" terms in bold, e.g.
Antioxidants are classified into two broad divisions, depending on whether they are soluble in water (hydrophilic) or lipids (hydrophobic or lipophilic).
This will help people who already know a little about the subject, and makes it easier to skim-read for those hunting specific pieces of information. Thanks.
Samsara (talk • contribs) 20:16, 2 March 2007 (UTC)[reply]
Would this be a suitable image? Samsara (talk • contribs) 20:19, 2 March 2007 (UTC)[reply]
I was told not to bold terms in articles in the DNA FAC. I'm not sure what to do, to bold or not to bold? I can't find any in-text bolding in AIDS, Cystic fibrosis or Down syndrome. I'll expand the history section a bit so it's comparable in length to the ones in the other featured articles, maybe more material on the discovery of the antioxidant effects of vitamins? I do need a top-right image according to the manual of style, if you object to this one, and I'm not over-keen on it myself, do you have any suggestions for new and eye-catching images? I think the pathway diagram you mention below is best kept in the enzymes section, since it is quite specific. TimVickers 20:46, 2 March 2007 (UTC)[reply]
Comment WP:MOSBOLD specifically states bolding should not be used for emphasis; italics should be used instead, sparingly. I've raised this point in GACs before, so I think FAs should follow :) I wouldn't object to italicizing select terms such as the ones Samsara mentioned. Fvasconcellos 22:06, 2 March 2007 (UTC)[reply]
What do you think of using the glutathione image? It is quite snazzy. TimVickers 20:53, 2 March 2007 (UTC)[reply]
I like the new header image, but maybe put the vegetables down with the tea? It's still not very informative per se, but a picture of antioxidant-containing foods seems appropriate in the foods section, possibly more than a teapot. Opabinia regalis 01:00, 3 March 2007 (UTC)[reply]
OK, I put that in on the suggestion of my tea-loving wife, but I suppose the vegetable image is more appropriate. TimVickers 01:21, 3 March 2007 (UTC)[reply]
Added the hydrophillic/phobic terms, but wikilinked them, as a compromise. TimVickers 22:21, 2 March 2007 (UTC)[reply]
It's not about those specific terms, it's the principle. I will oppose until the text can be made more manageable. And Fvasconcellos, what I'm suggesting is not emphasis. This is emphasis. Or that out of all my family, my shortest brother is the most famous. However, if I'm starting a new paragraph on the concept of emphasis, that's highlighting. If I'm talking about the concept of emphasis, that's emphasis. I hope that's clear. Samsara (talk • contribs) 23:37, 2 March 2007 (UTC)[reply]
Crystal clear, and pretty dense on my part. Fvasconcellos 01:28, 3 March 2007 (UTC)[reply]
I've tried to deal with this problem by breaking the "metabolites" and "enzymes" sections into new sub-sections. This should let the skimming reader find specific information more easily and also breaks up the text-heavy sections. What do you think? TimVickers 23:55, 2 March 2007 (UTC)[reply]
Added E-numbers to the list of antioxidants in the preservatives section.
Added MedlinePlus link, but the other is a commercial site so doesn't really satisfy WP:MOS-L. TimVickers 17:48, 5 March 2007 (UTC)[reply]
Anyway it's an unbelievably referenced article. NCurse work 06:13, 5 March 2007 (UTC)[reply]
The above discussion is preserved as an archive. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article review. No further edits should be made to this page.
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