Ferulic Acid Chemical Identity
Ferulic acid has the molecular formula C10H10O4 and a molecular weight of 194.2. The structure is a benzene ring carrying a hydroxyl and a methoxy group, attached to an acrylic acid side chain through a trans double bond. The conjugation between the ring and the double bond makes the molecule absorb strongly in the ultraviolet range, which is the basis of its detection by HPLC, and the carboxylic acid group makes it weakly acidic.
In plants, ferulic acid is rarely free. In rice bran it is bound by ester links to arabinoxylans in the cell wall and to triterpene alcohols and sterols in the oil fraction, and the free acid is released by alkaline or enzymatic hydrolysis. The natural source here is the bran of Oryza sativa L. Related rice bran materials include the ferulate esters of gamma-oryzanol, supplied as Rice Bran Extract 10–40% Gamma-Oryzanol, the 10:1 Rice Bran Extract Powder and a close structural relative, p-Coumaric Acid (4-Hydroxycinnamic Acid) 98%. Those have different compositions, while ferulic acid here is the free, purified acid.
The difference between ferulic and caffeic acid is a single methyl group, and between ferulic and p-coumaric acid a single methoxy group. Such small differences are easy to blur on a label, so the specification ties the name to the formula, the CAS number and the retention time of the main peak.












