2 replies to this topic

[stephen_b]

A recent study that found that Rhodiola rosea increased lifespan in fruit flies independently of dietary restriction (Extension of Drosophila Lifespan by Rhodiola rosea through a Mechanism Independent from Dietary Restriction (PMID 23704949; full text).

It made the argument that "the role of oxidative stress in aging has been somewhat marginalized recently", and cited two studies to support this claim:

• Overexpression of Mn superoxide dismutase does not increase life span in mice (PMID 19633237)
  
• The overexpression of major antioxidant enzymes does not extend the lifespan of mice (PMID 19077044; full text).

The second study cited another study, Extension of murine life span by overexpression of catalase targeted to mitochondria (PMID 15879174), which on the other hand did find a longevity increase in mice.

The difference between PMIDs 19077044 and 15879174? From 19077044:

Our data might appear to conflict with the study by Schriner et al. (2005), which showed that the overexpression of catalase increased the lifespan of transgenic mice. However, whereas Schriner et al. overexpressed catalase in mitochondria, catalase overexpression in our transgenic mouse occurred in the peroxisomes (Chen et al., 2003), where catalase is normally expressed (Zamocky & Koller, 1999).

It looks like mitochondria are the place to be if you want to decrease aging with antioxidants.

[niner]

Thanks, stephen. That's a great example of the numerous red herrings that have popped up around aging and antioxidants of late. It's not enough to overexpress an enzyme; it needs to be in the right place. Most chemical antioxidants suck, for various reasons. Even some of the sophisticated ones, like MitoQ can easily get into a pro-oxidant mode.

Edited by niner, 25 June 2013 - 12:56 AM.

[bew4lsh]

I'm of the opinion that c60oo's efficacy is explained by surface area, number of electrons it can accept, structural resilience, accessible electron affinity/ionization energy, and redox recombination. All those factors together make it versatile in that it can hand off radicals to enzymes, or combine two to form a stable molecule, repeatedly and continuously. I mention it here only because if I understand correctly, your average vitamins C/E are only able to donate two electrons before requiring recycling. You're getting a different level of efficiency out of c60 than you could from other molecules. I think that's relevant when comparing to the 'more is better' attitude we've been exposed to with conventional antioxidant supplementation.

Edited by bew4lsh, 24 August 2013 - 04:18 PM.