Howitz · Nature 2003 · in vitro biochemical and yeast experimental study · n=?

Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan.

Cited 3789 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Preclinical in vitro and yeast experimental study

PubMed 12939617 · doi:10.1038/nature01960 · record verified 2026-08-27

What was done

Researchers identified three classes of small-molecule sirtuin activators and evaluated the biochemical and biological effects of the polyphenol resveratrol. They measured human SIRT1 enzyme kinetics (Michaelis constant for acetylated substrate and NAD+), tested cell survival related to SIRT1-dependent deacetylation of p53, and measured the impact of resveratrol on Sir2 activation, DNA stability, and replicative lifespan in the budding yeast Saccharomyces cerevisiae.

What was found

Resveratrol lowered the Michaelis constant of SIRT1 for both acetylated substrate and NAD+, increased human cell survival via SIRT1-dependent p53 deacetylation, and in yeast, stimulated Sir2 activity, improved DNA stability, and extended lifespan by 70%.

Why it matters

This study provided the initial demonstration that small molecules like resveratrol can directly activate sirtuin deacetylases to pharmacologically mimic calorie restriction and extend lifespan in a model organism.

Limits

The study is limited to in vitro assays, human cell culture, and single-celled yeast (S. cerevisiae). It provides no pharmacokinetic, safety, or longevity data in multicellular animals or humans, and sample sizes or exact experimental replicates are not reported in the abstract.

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