It is easier to synthesize any substance from scratch than it is to transport it between even the nearest star systems. The only way such a resource could exist is if our entire understanding of physics is way off.

Earth gives us a wide range of organisms with different lifespans and metabolic rates. There are not that many species that live longer than us, and extremely few that live significantly longer than us. Even if something lived 100 times longer than us, only a very small portion of the galaxy would be traversible within a lifetime, and there is still no reason to go more than a few lightyears.