Vanillic acidVanillic acid is a dihydroxybenzoic acid derivative used as a flavoring agent. It is an oxidized form of vanillin. It is also an intermediate in the production of vanillin from ferulic acid.Occurrence in natureThe highest amount of vanillic acid in plants known so far is found in the root of Angelica sinensis, an herb indigenous to China, which is used in traditional Chinese medicine.Occurrences in food, obtained from the fruit of the açaí palm, is rich in vanillic acid. It is one of the main natural phenols in argan oil. It is also found in wine and vinegar.MetabolismVanillic acid is one of the main catechins metabolites found in humans after consumption of green tea infusions.SynthesisVanillic acid can be obtained from the oxidation of vanillin by various oxidizing agents.