cis-Urocanic acid (cis-UCA) is a chemical compound produced by
ultraviolet irradiation of
trans-urocanic acid, a metabolite naturally formed in the body from
histidine. cis-Urocanic acid is suspected of involvement in the development of
skin cancer. It acts as an
immunosuppressant through action as an
agonist of the
5-HT2A receptor, and blocking this receptor has been shown to reduce cis-UCA mediated photocarcinogenesis.[1][2][3] However the
immunomodulatory effects of cis-UCA are complex and also involve other pathways, and at low levels it shows
antiinflammatory actions and may be protective against UV damage in the
cornea and
retina.[4][5][6][7][8][9]
^Shen L, Ji HF (September 2009). "Molecular basis for cis-urocanic acid as a 5-HT(2A) receptor agonist". Bioorganic & Medicinal Chemistry Letters. 19 (18): 5307–5309.
doi:
10.1016/j.bmcl.2009.07.143.
PMID19683920.
^Menezes AC, Raposo S, Simões S, Ribeiro H, Oliveira H, Ascenso A (March 2016). "Prevention of Photocarcinogenesis by Agonists of 5-HT1A and Antagonists of 5-HT2A Receptors". Molecular Neurobiology. 53 (2): 1145–1164.
doi:
10.1007/s12035-014-9068-z.
PMID25589005.
S2CID14282500.
^Norval M, El-Ghorr AA (September 2002). "Studies to determine the immunomodulating effects of cis-urocanic acid". Methods. 28 (1): 63–70.
doi:
10.1016/s1046-2023(02)00210-4.
PMID12231189.