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Chemical Compound Review

urocanic acid     (E)-3-(3H-imidazol-4-yl)prop- 2-enoic acid

Synonyms: urocanate, zlchem 24, PubChem9875, AC1LEIQR, SureCN15417, ...
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Disease relevance of urocanic acid


High impact information on urocanic acid


Chemical compound and disease context of urocanic acid


Biological context of urocanic acid


Anatomical context of urocanic acid


Associations of urocanic acid with other chemical compounds

  • It was then found that: (i) pK of these proton donors (pK = 6.13 +/- 0.07) was quasi-identical to that of trans-urocanic acid (6.10), and (ii) the amount of urocanic acid present in stratum corneum was sufficient in itself to explain the acidic level as measured with pH meter (R = 0.8484, n = 10, p = 0.00136) [23].
  • In mice bearing a null mutation for MT-I and -II, we found that immunoprotection by the isoflavonoid 4',7-dihydroxyisoflavane (equol) against solar-simulated UV radiation (SSUV) or exogenous cis-urocanic acid was abrogated [24].
  • A blister induced in the rat hind footpad was used to examine the effects of slowly perfused cis-urocanic acid on cutaneous blood flow. cis-Urocanic acid but not trans-urocanic acid increased microvascular flow by a mechanism largely dependent on the combined activity of the neuropeptides, substance P and calcitonin gene-related peptide [19].
  • N-acetylcysteine proved not to have any effect on the photoisomerization of trans-urocanic acid (UCA) to its cis-form in vitro; at equilibrium, approximately 55% cis-UCA was formed [25].
  • One initiator of this complex process is cis-urocanic acid (cis-UCA), which is formed from the naturally occurring trans isomer in the epidermis on absorption of UV. cis-UCA has been shown to have immunomodulating properties in a variety of in vivo and in vitro experimental systems, although its mechanism of action is not yet clear [26].

Gene context of urocanic acid


Analytical, diagnostic and therapeutic context of urocanic acid


  1. Immunosuppression by ultraviolet B radiation: initiation by urocanic acid. Noonan, F.P., De Fabo, E.C. Immunol. Today (1992) [Pubmed]
  2. Differential effects of a monoclonal antibody to cis-urocanic acid on the suppression of delayed and contact hypersensitivity following ultraviolet irradiation. Moodycliffe, A.M., Bucana, C.D., Kripke, M.L., Norval, M., Ullrich, S.E. J. Immunol. (1996) [Pubmed]
  3. Differential photoimmunoprotection by sunscreen ingredients is unrelated to epidermal cis urocanic acid formation in hairless mice. Reeve, V.E., Boehm-Wilcox, C., Bosnic, M., Reilly, W.G. J. Invest. Dermatol. (1994) [Pubmed]
  4. UVA exposure affects UVB and cis-urocanic acid-induced systemic suppression of immune responses in Listeria monocytogenes-infected Balb/c mice. Garssen, J., de Gruijl, F., Mol, D., de Klerk, A., Roholl, P., Van Loveren, H. Photochem. Photobiol. (2001) [Pubmed]
  5. Epidermal cis-urocanic acid levels correlate with lower specific cellular immune responses after hepatitis B vaccination of ultraviolet B-exposed humans. Sleijffers, A., Kammeyer, A., de Gruijl, F.R., Boland, G.J., van Hattum, J., van Vloten, W.A., van Loveren, H., Teunissen, M.B., Garssen, J. Photochem. Photobiol. (2003) [Pubmed]
  6. Spectroscopic and dynamic studies of the epidermal chromophores trans-urocanic acid and eumelanin. Simon, J.D. Acc. Chem. Res. (2000) [Pubmed]
  7. Heme oxygenase induction mediates the photoimmunoprotective activity of UVA radiation in the mouse. Reeve, V.E., Tyrrell, R.M. Proc. Natl. Acad. Sci. U.S.A. (1999) [Pubmed]
  8. Epidermal trans-urocanic acid and the UV-A-induced photoaging of the skin. Hanson, K.M., Simon, J.D. Proc. Natl. Acad. Sci. U.S.A. (1998) [Pubmed]
  9. IL-12 prevents the inhibitory effects of cis-urocanic acid on tumor antigen presentation by Langerhans cells: implications for photocarcinogenesis. Beissert, S., Rühlemann, D., Mohammad, T., Grabbe, S., El-Ghorr, A., Norval, M., Morrison, H., Granstein, R.D., Schwarz, T. J. Immunol. (2001) [Pubmed]
  10. Cis-urocanic acid stimulates human peripheral blood monocyte prostaglandin E2 production and suppresses indirectly tumor necrosis factor-alpha levels. Hart, P.H., Jones, C.A., Jones, K.L., Watson, C.J., Santucci, I., Spencer, L.K., Finlay-Jones, J.J. J. Immunol. (1993) [Pubmed]
  11. Pyridoxine supplementation protects mice from suppression of contact hypersensitivity induced by 2-acetyl-4-tetrahydroxybutylimidazole (THI), ultraviolet B radiation (280-320 nm), or cis-urocanic acid. Reeve, V.E., Bosnic, M., Boehm-Wilcox, C., Cope, R.B. Am. J. Clin. Nutr. (1995) [Pubmed]
  12. Histamine involvement in UVB- and cis-urocanic acid-induced systemic suppression of contact hypersensitivity responses. Hart, P.H., Jaksic, A., Swift, G., Norval, M., el-Ghorr, A.A., Finlay-Jones, J.J. Immunology (1997) [Pubmed]
  13. A garlic extract protects from ultraviolet B (280-320 nm) radiation-induced suppression of contact hypersensitivity. Reeve, V.E., Bosnic, M., Rozinova, E., Boehm-Wilcox, C. Photochem. Photobiol. (1993) [Pubmed]
  14. Carnosine (beta-alanylhistidine) protects from the suppression of contact hypersensitivity by ultraviolet B (280-320 nm) radiation or by cis urocanic acid. Reeve, V.E., Bosnic, M., Rozinova, E. Immunology (1993) [Pubmed]
  15. Evidence that ultraviolet B radiation induces tolerance and impairs induction of contact hypersensitivity by different mechanisms. Shimizu, T., Streilein, J.W. Immunology (1994) [Pubmed]
  16. Cis-urocanic acid as a mediator of ultraviolet-light-induced immunosuppression. Gruner, S., Oesterwitz, H., Stoppe, H., Henke, W., Eckert, R., Sönnichsen, N. Semin. Hematol. (1992) [Pubmed]
  17. Cis-urocanic-acid-induced suppression of contact hypersensitivity in Monodelphis domestica is prevented by ultraviolet A radiation/photoreactivating light. Reeve, V.E., Ley, R.D. Int. Arch. Allergy Immunol. (1997) [Pubmed]
  18. Refractoriness of UVA-induced protection from photoimmunosuppression correlates with heme oxygenase response to repeated UVA exposure. Reeve, V.E., Domanski, D. Photochem. Photobiol. (2002) [Pubmed]
  19. cis-Urocanic acid stimulates neuropeptide release from peripheral sensory nerves. Khalil, Z., Townley, S.L., Grimbaldeston, M.A., Finlay-Jones, J.J., Hart, P.H. J. Invest. Dermatol. (2001) [Pubmed]
  20. Histamine and cis-urocanic acid augment tumor necrosis factor-alpha mediated induction of keratinocyte intercellular adhesion molecule-1 expression. Mitra, R.S., Shimizu, Y., Nickoloff, B.J. J. Cell. Physiol. (1993) [Pubmed]
  21. Cis-urocanic acid, a product formed by ultraviolet B irradiation of the skin, initiates an antigen presentation defect in splenic dendritic cells in vivo. Noonan, F.P., De Fabo, E.C., Morrison, H. J. Invest. Dermatol. (1988) [Pubmed]
  22. A monoclonal antibody to cis-urocanic acid prevents the ultraviolet-induced changes in Langerhans cells and delayed hypersensitivity responses in mice, although not preventing dendritic cell accumulation in lymph nodes draining the site of irradiation and contact hypersensitivity responses. el-Ghorr, A.A., Norval, M. J. Invest. Dermatol. (1995) [Pubmed]
  23. Evidence for the existence of a self-regulated enzymatic process within the human stratum corneum -an unexpected role for urocanic acid. Krien, P.M., Kermici, M. J. Invest. Dermatol. (2000) [Pubmed]
  24. Isoflavonoid photoprotection in mouse and human skin is dependent on metallothionein. Widyarini, S., Allanson, M., Gallagher, N.L., Pedley, J., Boyle, G.M., Parsons, P.G., Whiteman, D.C., Walker, C., Reeve, V.E. J. Invest. Dermatol. (2006) [Pubmed]
  25. The protective effect of N-acetylcysteine on UVB-induced immunosuppression by inhibition of the action of cis-urocanic acid. Hemelaar, P.J., Beijersbergen van Henegouwen, G.M. Photochem. Photobiol. (1996) [Pubmed]
  26. Studies to determine the immunomodulating effects of cis-urocanic acid. Norval, M., El-Ghorr, A.A. Methods (2002) [Pubmed]
  27. Interferon-gamma is involved in photoimmunoprotection by UVA (320-400 nm) radiation in mice. Reeve, V.E., Bosnic, M., Nishimura, N. J. Invest. Dermatol. (1999) [Pubmed]
  28. Contrasting effects of ultraviolet A1 and ultraviolet B exposure on the induction of tumour necrosis factor-alpha in human skin. Skov, L., Hansen, H., Allen, M., Villadsen, L., Norval, M., Barker, J.N., Simon, J., Baadsgaard, O. Br. J. Dermatol. (1998) [Pubmed]
  29. cis-urocanic acid suppression of contact hypersensitivity induction is mediated via tumor necrosis factor-alpha. Kurimoto, I., Streilein, J.W. J. Immunol. (1992) [Pubmed]
  30. Enhancement of riboflavin-mediated photo-oxidation of glucose 6-phosphate dehydrogenase by urocanic acid. Silva, E., Herrera, L., Edwards, A.M., de la Fuente, J., Lissi, E. Photochem. Photobiol. (2005) [Pubmed]
  31. Molecular aspects of UVB-induced immunosuppression. Garssen, J., Vandebriel, R.J., van Loveren, H. Arch. Toxicol. Suppl. (1997) [Pubmed]
  32. Inhibition of skin allograft rejection and acute graft-versus-host disease by cis-urocanic acid. Gruner, S., Diezel, W., Stoppe, H., Oesterwitz, H., Henke, W. J. Invest. Dermatol. (1992) [Pubmed]
  33. Fluorescent light activates the immunomodulator cis-urocanic acid in vitro: implications for patients with systemic lupus erythematosus. McGrath, H., Bell, J.M., Haycock, J.W. Ann. Rheum. Dis. (1994) [Pubmed]
  34. Differential suppression of the human mixed epidermal cell lymphocyte reaction (MECLR) and mixed lymphocyte reaction (MLR) by cis-urocanic acid. Hurks, H.M., Out-Luiting, C., Van den Molen, R.G., Vermeer, B.J., Claas, F.H., Mommaas, A.M. Photochem. Photobiol. (1997) [Pubmed]
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