The present invention relates to a process of extraction and purification of a stilbenoid, pterostilbene, from botanical sources. The process involves obtaining pterostilbene having high degree of purity and the present invention also relates to pure form of pterostilbene obtained. The invention also relates to complexing the pterostilbene with carriers such as cyclodextrin for improving its water solubility and bioavailability. The present invention also describes a process for inhibition of Histone Deacetylases using pterostilbene optionally along with a carrier, and a method of managing Poly Glutamine repeat disorders by the administration of pterostilbene optionally along with a carrier.
