In the past decade, a large number of benzaldehyde and benzoate derivatives have been isolated from plants and identified as tyrosinase inhibitors, including benzoic acid, benzaldehyde, anisic acid, anisaldehyde, cinnamic acid, and methoxycinnamic acid from the roots of Pulsatilla cernua, 4-substituted benzaldehydes from cumin, 2-hydroxy-4-methoxybenzaldehyde from roots of Mondia whitei, p-coumaric acid from the leaves of Panax ginseng, hydroxycinnamoyl derivatives from green coffee bean, and vanillic acid and its derivatives from black rice bran.

The aldehyde group is known to react with biologically important nucleophilic groups such as sulfhydryl, amino, and hydroxyl groups. The tyrosinase inhibitory mechanism of benzaldehyde-type inhibitors comes from their ability to form a Schiff base with a primary amino group in the enzyme.

In contrast, benzoate inhibits tyrosinase by a copper chelating mechanism and belongs to a typical HA-type acid tyrosinase inhibitor, whose inhibitory mechanism involves the interaction between the non-ionized form of the inhibitor and the copper in the active site of the enzyme.

In terms of inhibitory strength, all the naturally occurring benzaldehyde and benzoate derivatives listed above showed only weak-to-moderate tyrosinase inhibitory activity while none are stronger than kojic acid.