Homogentisic acid

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Homogentisic acid
Homogentisic acid.svg
IUPAC name
(2,5-Dihydroxyphenyl)acetic acid
Other names
Melanic acid
3D model (Jmol)
ECHA InfoCard 100.006.540
MeSH Homogentisic+acid
Molar mass 168.15 g·mol−1
Melting point 150 to 152 °C (302 to 306 °F; 423 to 425 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Homogentisic acid (2,5-dihydroxyphenylacetic acid) is a phenolic acid found in Arbutus unedo (strawberry-tree) honey.[1] It is also present in the bacterial plant pathogen Xanthomonas campestris pv. phaseoli[2] as well as in the yeast Yarrowia lipolytica[3] where it is associated with the production of brown pigments.

It is less commonly known as melanic acid, the name chosen by William Prout.

Human pathology[edit]

Accumulation of excess homogentisic acid and its oxide, named alkapton, is a result of the failure of the enzyme homogentisic acid 1,2-dioxygenase (typically due to a mutation) in the degradative pathway of tyrosine, consequently associated with alkaptonuria.[4]


It is an intermediate in the catabolism of aromatic amino acids such as phenylalanine and tyrosine.


  1. ^ Paolo Cabras; Alberto Angioni; Carlo Tuberoso; Ignazio Floris; Fabiano Reniero; Claude Guillou; Stefano Ghelli (1999). "Homogentisic Acid: A Phenolic Acid as a Marker of Strawberry-Tree (Arbutus unedo) Honey". J. Agric. Food Chem. 47 (10): 4064–4067. doi:10.1021/jf990141o. 
  2. ^ Goodwin PH, Sopher CR (1994). "Brown pigmentation of Xanthomonas campestris pv. phaseoli associated with homogentisic acid". Canadian Journal of Microbiology. 40 (1): 28–34. doi:10.1139/m94-005. 
  3. ^ Alexandra Carreira; Luísa M. Ferreira; Virgílio Loureiro (2001). "Brown Pigments Produced by Yarrowia lipolytica Result from Extracellular Accumulation of Homogentisic Acid". Appl Environ Microbiol. 67 (8): 3463–3468. doi:10.1128/AEM.67.8.3463-3468.2001. 
  4. ^ Phornphutkul C, Introne WJ, Perry MB, et al. (2002). "Natural history of alkaptonuria". New England Journal of Medicine. 347 (26): 2111–21. doi:10.1056/NEJMoa021736. PMID 12501223.