Resveratrol in and of itself is likely not terribly interesting for work on longevity - and certainly not worthy of the hype surrounding it. The same probably goes for sirtuins in general. This, however, is still a good example of work on tracing back the pathways of action of a metabolic change agent: "Research has previously suggested that resveratrol acts through activation of the sirtuin (SIR) gene family. This gene pathway, though controversial, has been implicated in life extension across several species. It has been reported that SIR extends lifespan in much the same way as caloric restriction which itself in turn may activate SIR. It has remained unclear however if resevertrol directly activates SIR or if it acts on SIR indirectly via another intermediary biochemical pathway. The current study successfully answered that question. Using several cell biology techniques the authors were able to demonstrate that resveratrol actually functions to activate SIR indirectly. They showed that resveratrol is really a phosphodiesterase inhibitor (PDE4). They demonstrated that reducing PDE4 allows cyclic AMP (cAMP) levels in the cells to rise. cAMP then increases the activity of AMPK which next increases NAD+ which finally increases SIR. This elegant study then went on to prove that the same life extending benefits of resveratrol could be achieved in rats by administering them the PDE4 inhibitor rolipram. ... inhibiting PDE4 with rolipram reproduces all of the metabolic beneﬁts of resveratrol, including prevention of diet-induced obesity and an increase in mitochondrial function, physical stamina, and glucose tolerance in mice. "