Pterostilbene

Pterostilbene (CAS 537-42-8, PubChem CID 5281727) is a stilbenoid: two aromatic rings joined by a trans ethene bridge, molecular formula C16H16O3, molecular weight 256.30. Its systematic name is 4-[(E)-2-(3,5-dimethoxyphenyl)ethenyl]phenol, and the trade also writes it as trans-3,5-dimethoxy-4'-hydroxystilbene or, more tellingly, 3,5-dimethoxyresveratrol. That second name is the whole story of the molecule: pterostilbene is resveratrol with the two meta hydroxyls of one ring capped as methyl ethers, leaving a single free phenolic hydroxyl on the other ring. That combination — aryl methyl ethers and a free phenol on the same skeleton — is also what fixes its tariff position, because it makes the compound an ether-phenol rather than a plain polyphenol. For a formulator the methylation moves the handling properties in a predictable direction. Set against resveratrol, pterostilbene's computed partition coefficient rises from XLogP 3.1 to 3.8, its topological polar surface area falls from 60.7 to 38.7 square angstroms, and its hydrogen-bond donor count drops from three to one. In practice that means a markedly more lipophilic powder. It goes into ethanol, MCT and other lipid vehicles readily and suits softgels, oil-filled capsules and lipid emulsions, while aqueous beverages need a solubilised, emulsified or cyclodextrin-complexed presentation because the free powder is practically insoluble in water. Like every stilbene it photoisomerises, so trans purity is a live specification line and light-protected packing and in-process handling are not optional. Pterostilbene occurs naturally in almonds, in Vaccinium berries including blueberries, in grape leaves and vines, and in the heartwood of Pterocarpus species, but at concentrations far too low to support extraction at bulk scale. Commercial material, Thovek's included, is chemically synthesised. That reads as a plus on most buyer checklists — the powder is vegan, non-animal, non-GMO and free of the major allergen groups, and specifically is not almond-derived despite the natural occurrence — and it shifts the analytical burden away from pesticide residues and towards residual solvents, which are controlled to ICH Q3C limits with the route's full solvent profile disclosed on the certificate of analysis. There is no USP or Ph. Eur. monograph for pterostilbene, so lots release against an in-house specification: 99.0% minimum by HPLC as the trans isomer, cis isomer reported, loss on drying, residue on ignition, elemental impurities to USP <232> and <233>, and a full microbiological panel. Market access differs sharply by destination, and buyers should confirm the novel-food or new-dietary-ingredient position in their target market before committing to a launch.