Umbellic acid

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Umbellic acid
Chemical structure of umbellic acid
IUPAC name
(E)-3-(2,4-dihydroxyphenyl)prop-2-enoic acid
Other names
2,4-Dihydroxycinnamic acid
(E)-2,4-Dihydroxycinnamic acid
(2E)-3-(2,4-Dihydroxyphenyl)acrylic acid
ChemSpider 393925
Jmol-3D images Image
PubChem 446611
Molar mass 180.16 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Umbellic acid (2,4-dihydroxycinnamic acid) is a hydroxycinnamic acid. It is an isomer of caffeic acid.

It is a precursor in the umbelliferone biosynthesis pathway. Umbelliferone is a phenylpropanoid and as such is synthesized from L-phenylalanine, which in turn is produced via the shikimate pathway. Phenylalanine is lysated into cinnamic acid, followed by hydroxylation by cinnamate 4-hydroxylase to yield 4-coumaric acid. The 4-coumaric acid is again hydroxylated by cinnamate/coumarate 2-hydroxylase to yield 2,4-dihydroxy-cinnamic acid followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group. Finally an intramolecular attack from the hydroxyl group of C2' to the carboxylic acid group closes the ring and forms the lactone umbelliferone.

L-phenylalanine  \xrightarrow{PAL} Cinnamic acid \xrightarrow{C4H} para-Coumaric acid \xrightarrow{C2H} 2,4-Dihydroxycinnamic acid \longrightarrow Umbelliferone

The enzyme 4-hydroxycinnamate decarboxylase, induced in bacteria species such as Klebsiella oxytoca, works also with p-coumaric acid analogs such as E-2,4-dihydroxycinnamic acid.[1]


  1. ^ Hashidoko, Y; Tanaka, T; Tahara, S (2001). "Induction of 4-hydroxycinnamate decarboxylase in Klebsiella oxytoca cells exposed to substrates and non-substrate 4-hydroxycinnamate analogs". Bioscience, biotechnology, and biochemistry 65 (12): 2604–12. doi:10.1271/bbb.65.2604. PMID 11826954. 

External links[edit]

The dictionary definition of umbellic acid at Wiktionary