6-Hydroxymelatonin

6-Hydroxymelatonin (6-OHM) is a naturally occurring, endogenous, major active metabolite of melatonin.^[1] 6-Hydroxymelatonin is produced as a result of the enzymatic conversion of melatonin through hydroxylation.^[2] Similar to melatonin, 6-OHM is a full agonist of the MT₁ and MT₂ receptors.^[3][4] It is also an antioxidant and neuroprotective, and is even more potent in this regard relative to melatonin.^[5][6]

6-Hydroxymelatonin

Names
Preferred IUPAC name N-[2-(6-Hydroxy-5-methoxy-1H-indol-3-yl)ethyl]acetamide
Other names 6-Oxymelatonin
Identifiers
CAS Number	2208-41-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:198
ChemSpider	1794
ECHA InfoCard	100.164.426
KEGG	C05643
PubChem CID	1864
UNII	TV437T5077 Y
CompTox Dashboard (EPA)	DTXSID00176577
InChI InChI=1S/C13H16N2O3/c1-8(16)14-4-3-9-7-15-11-6-12(17)13(18-2)5-10(9)11/h5-7,15,17H,3-4H2,1-2H3,(H,14,16) Key: OMYMRCXOJJZYKE-UHFFFAOYSA-N InChI=1/C13H16N2O3/c1-8(16)14-4-3-9-7-15-11-6-12(17)13(18-2)5-10(9)11/h5-7,15,17H,3-4H2,1-2H3,(H,14,16) Key: OMYMRCXOJJZYKE-UHFFFAOYAK
SMILES CC(=O)NCCC1=CNC2=CC(=C(C=C21)OC)O
Properties
Chemical formula	C13H16N2O3
Molar mass	248.282 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

Role in metabolism

The determination of 6-OHM in human urine has been used to track the metabolism and excretion of melatonin using LC-MS/MS, providing quantifiable insights into circadian rhythm regulation and its oxidative role as a biomarker.^[7] 6-OHM is one of four of the primary metabolic products of melatonin in the liver and is also a byproduct of its breakdown due to exposure to light. It is known to be very effective in protecting cells from oxidative damage caused by ultraviolet (UV) radiation.^[8] Based on comparisons with other melatonin-related compounds, it is suggested that the protective effects of 6-OHM in mitigating oxidative stress are primarily attributed to their ability to scavenge free radicals.^[9]

See also

• N-Acetylserotonin (normelatonin)
• 5-Methoxytryptamine
• Melatonin