Ethyl protocatechuate

Ethyl protocatechuate (CAS 3943-89-3), also known as ethyl 3,4-dihydroxybenzoate, is a naturally occurring phenolic ester found in various plant sources. It carries no assigned E-code and is classified under HS code 29053990. It is the ethyl ester of protocatechuic acid, sharing the catechol moiety responsible for its bioactive properties.

In cosmetic formulations, its catechol ring donates hydrogen atoms to neutralise free radicals, slowing oxidative degradation of oils and active ingredients. In food and pharmaceutical applications, it functions as a preservative and antioxidant, inhibiting lipid peroxidation and microbial growth at low concentrations. It also absorbs UV radiation in the 280-320 nm range, providing photoprotective stabilisation.

Ethyl protocatechuate is supplied as a pale yellow to beige crystalline powder, with grades suitable for cosmetic, food, and pharmaceutical use. Suppliers operating under REACH compliance should provide a full safety dossier. Packaging typically ranges from kilogram-scale laboratory quantities to multi-kilogram industrial drums.