What do you think its overall benefits are then, if not a particular benefit or set of benefits?  True, it is methylated resveratrol, but then codeine is methylated morphine.  I tried using the pterostilbene Swanson's used to sell and there was no changein my blood sugar.

The heartwood of the malabar kino tree is the richest source of pterostilbene according to the literature.  Maybe there is some in the bark.  (Now if it ware a Malomar tree that would be interesting....)

The Chinese botanical extract industry is much more developed than  India's.  China's highly publicized problems have been in other industries.  Not to say there aren't problems possible anywhere, and you can easily purchase counterfeit botanicals if you aren't careful-- but even Japan's sophisticated pharmaceutical industry had major problems with tryptophan and eosinophilia.  Indian herbal and botanical products are problematic, specifically heavey metal poisoning.  Spice extracts are another matter, but for the most part they are much less developed than China, with a fraction of the capacity.   

If you want high purity pterostilbene-- and I have doubts about every supplement claiming to contain pterostilbene -- then try http://www.alexis-biochemicals.com/Pterostilbene.5+M5a8173466db.0.html  .  It's kind of pricey, but it's the real thing. Or you could methylate resveratrol in your kitchen: http://tinyurl.com/pc2g72


Some of the lab work with pterostilbene looks promising, but there is still a problem of getting enough of it at reasonable cost forlarge animal studies.  At this point, resveratrol appears to have many if not most of the same properties, and there are several sources of proven quality available, with or without quercetin or luteolin or piperine or Tween-80.