Phenolic acid

Included in that class are substances containing a phenolic ring and an organic carboxylic acid function (C6-C1 skeleton).

Natural phenols in horse grams (Macrotyloma uniflorum) are mostly phenolic acids, namely 3,4-dihydroxy benzoic, p-hydroxy benzoic, vanillic, caffeic, p-coumaric, ferulic, syringic, and sinapinic acids.

[citation needed] Phenolic acids can be found in several mushroom-forming species of basidiomycetes.

[2] It is also a part of the humic substances, which are the major organic constituents of soil humus.

[3] Immobilized Candida antarctica lipase can be used to catalyze the direct acetylation of flavonoids with phenolic acids.