Abstract
Exogenous melatonin is widely used for sleep disorders and has potential value in neuroprotection, cardioprotection and as an antioxidant. Here, a novel method is described for the determination of melatonin and six metabolites in mouse urine by use of q1LC-MS/MS and GC-MS. LC-MS/MS is used for the measurement of melatonin, N1-acetyl-5-methoxykynuramine (AMK), N 1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and 6-hydroxymelatonin (6-HMEL), while GC/MS is used for the determination of N-[2-(5-methoxy-2-oxo-2,3-dihydro-1H-indol-3-yl)-ethyl]-acetamide (2-OMEL) and cyclic 3-hydroxymelatonin (3-HMEL) with detection limits on column of 0.02-0.5 pmol, depending on the metabolite. Following oral administration of melatonin to mice, a 0-24 hr urine collection revealed the presence of melatonin (0.2% dose), 6-HMEL (37.1%) and NAS (3.1%) comprising >90% of the total metabolites; AMK and AFMK were also detected at 0.01% each; 2-OMEL was found at 2.2% of the dose, which is >100 times more than the AMK/AFMK pathway, and comprises >5% of the melatonin-related material detected in mouse urine. 3-HMEL was largely found as a sulfate conjugate. These studies establish sensitive assays for determination of six melatonin metabolites in mouse urine and confirm the potential for antioxidant activity of melatonin through the identification in vivo of AMK and AFMK, ring-opened metabolites with a high capacity for scavenging reactive oxygen species.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 343-349 |
| Number of pages | 7 |
| Journal | Journal of Pineal Research |
| Volume | 40 |
| Issue number | 4 |
| DOIs | |
| State | Published - May 2006 |
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Keywords
- Antioxidants
- Melatonin
- Mouse
- Urine
ASJC Scopus subject areas
- Endocrinology
Cite this
Urinary metabolites and antioxidant products of exogenous melatonin in the mouse. / Ma, Xiaochao; Idle, Jeffrey R.; Krausz, Kristopher W.; Tan, Dun Xian; Ceraulo, Leopoldo; Gonzalez, Frank J.
In: Journal of Pineal Research, Vol. 40, No. 4, 05.2006, p. 343-349.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Urinary metabolites and antioxidant products of exogenous melatonin in the mouse
AU - Ma, Xiaochao
AU - Idle, Jeffrey R.
AU - Krausz, Kristopher W.
AU - Tan, Dun Xian
AU - Ceraulo, Leopoldo
AU - Gonzalez, Frank J.
PY - 2006/5
Y1 - 2006/5
N2 - Exogenous melatonin is widely used for sleep disorders and has potential value in neuroprotection, cardioprotection and as an antioxidant. Here, a novel method is described for the determination of melatonin and six metabolites in mouse urine by use of q1LC-MS/MS and GC-MS. LC-MS/MS is used for the measurement of melatonin, N1-acetyl-5-methoxykynuramine (AMK), N 1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and 6-hydroxymelatonin (6-HMEL), while GC/MS is used for the determination of N-[2-(5-methoxy-2-oxo-2,3-dihydro-1H-indol-3-yl)-ethyl]-acetamide (2-OMEL) and cyclic 3-hydroxymelatonin (3-HMEL) with detection limits on column of 0.02-0.5 pmol, depending on the metabolite. Following oral administration of melatonin to mice, a 0-24 hr urine collection revealed the presence of melatonin (0.2% dose), 6-HMEL (37.1%) and NAS (3.1%) comprising >90% of the total metabolites; AMK and AFMK were also detected at 0.01% each; 2-OMEL was found at 2.2% of the dose, which is >100 times more than the AMK/AFMK pathway, and comprises >5% of the melatonin-related material detected in mouse urine. 3-HMEL was largely found as a sulfate conjugate. These studies establish sensitive assays for determination of six melatonin metabolites in mouse urine and confirm the potential for antioxidant activity of melatonin through the identification in vivo of AMK and AFMK, ring-opened metabolites with a high capacity for scavenging reactive oxygen species.
AB - Exogenous melatonin is widely used for sleep disorders and has potential value in neuroprotection, cardioprotection and as an antioxidant. Here, a novel method is described for the determination of melatonin and six metabolites in mouse urine by use of q1LC-MS/MS and GC-MS. LC-MS/MS is used for the measurement of melatonin, N1-acetyl-5-methoxykynuramine (AMK), N 1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and 6-hydroxymelatonin (6-HMEL), while GC/MS is used for the determination of N-[2-(5-methoxy-2-oxo-2,3-dihydro-1H-indol-3-yl)-ethyl]-acetamide (2-OMEL) and cyclic 3-hydroxymelatonin (3-HMEL) with detection limits on column of 0.02-0.5 pmol, depending on the metabolite. Following oral administration of melatonin to mice, a 0-24 hr urine collection revealed the presence of melatonin (0.2% dose), 6-HMEL (37.1%) and NAS (3.1%) comprising >90% of the total metabolites; AMK and AFMK were also detected at 0.01% each; 2-OMEL was found at 2.2% of the dose, which is >100 times more than the AMK/AFMK pathway, and comprises >5% of the melatonin-related material detected in mouse urine. 3-HMEL was largely found as a sulfate conjugate. These studies establish sensitive assays for determination of six melatonin metabolites in mouse urine and confirm the potential for antioxidant activity of melatonin through the identification in vivo of AMK and AFMK, ring-opened metabolites with a high capacity for scavenging reactive oxygen species.
KW - Antioxidants
KW - Melatonin
KW - Mouse
KW - Urine
UR - http://www.scopus.com/inward/record.url?scp=33645449734&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33645449734&partnerID=8YFLogxK
U2 - 10.1111/j.1600-079X.2006.00321.x
DO - 10.1111/j.1600-079X.2006.00321.x
M3 - Article
VL - 40
SP - 343
EP - 349
JO - Journal of Pineal Research
JF - Journal of Pineal Research
SN - 0742-3098
IS - 4
ER -