Phenolic acids or phenolcarboxylic acids are types of aromatic acid compound. Included in that class are substances containing a phenolic ring and an organic carboxylic acid function (C6-C1 skeleton). Two important naturally occurring types of phenolic acids are hydroxybenzoic acids and hydroxycinnamic acids, which are derived from non-phenolic molecules of benzoic and cinnamic acid, respectively.
Phenolic acids can be found in many plant species. Their content in
dried fruits can be high.
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.
Phenolic acids can be found in mushroom
Basidiomycetes species. It is also a part of the  humic substances, which are the major organic constituents of soil humus.
Many phenolic acids can be found in
lipase can be used to catalyze the direct acetylation of flavonoids with phenolic acids. Candida antarctica
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