Erucic Acid Ethyl-d5 Ester is labelled Erucic Acid Ethyl Ester (E649905) which is the ethyl ester of Erucic acid (E649900) which is a long-chain alcohol that acts as an inhibitor of fatty acid oxidation in the heart. Erucic acid originates in rapeseed plants, and is the major fatty acid constituent of rapeseed plant oil extracts and canola oil.