A rather "shocking" news: Resveratrol does not activate Sirt1, a longevity enzyme.

Recent studies by Pfizer and Amgen cast doubt on the manner in which the
health supplement "resveratrol" (R3) is said to work. R3 is a natural product
found in red grapes (and red wines), and is believed to delay the process
of aging. In 2003 David Sinclair's group at Harvard Medical School reported
that R3 activates an enzyme called SIRT1. This activation is thought to
produce the benefits of a caloric restriction (CR) diet even among those
with high fat and high caloric intake. Surprisingly, however, in October
2009, Amgen offered experimental results that indicate R3 does not, in fact,
activate SIRT1. Pfizer, in January 2010, offers similar results, showing
that R3 (and its synthetic derivatives such as SRT1720) do not active SIRT1
and did not reduce blood sugar in mice fed a high fat diet. This last effect
(or lack thereof) is in direct contradiction to the previous R3 research
published during 2003-2007 by David Sinclair's group in Nature or Science.
In short, Pfizer and Amgen are saying that R3 doesn't work in the way people
have been told.

http://singularityhub.com/tag/srt1720/

However, dont' panic! R3 still activates the tumor suppressing kinase AMPK,
and inactivates the oncogenic kinase PAK1, eventually activating the longevity
transcription factor "FOXO". Nevertheless, the pharmaceutical company "Sirtris"
, that David Sinclair created in Cambridge/Boston, and developed SRT1720
and other so-called "Sirt1 activators", by using a "wrong" (misleading)
assay system, is clearly facing a great crisis.