The identification of the UV degradants of melatonin and their ability to scavenge free radicals

Maharaj, Deepa S; Anoopkumar-Dukie, Shailendra; Glass, Beverley D; Lack, Barbara A; Daya, Santylal

Title: The identification of the UV degradants of melatonin and their ability to scavenge free radicals
Creator: Maharaj, Deepa S
Creator: Anoopkumar-Dukie, Shailendra
Creator: Glass, Beverley D
Creator: Antunes, Edith M
Creator: Lack, Barbara A
Creator: Walker, Roderick B
Creator: Daya, Santylal
Subject: To be catalogued
Date Issued: 2002
Date: 2002
Type: text
Type: article
Identifier: http://hdl.handle.net/10962/184303
Identifier: vital:44198
Identifier: xlink:href="https://doi.org/10.1034/j.1600-079X.2002.01866.x"
Description: Ultraviolet (UV) light is known to induce the generation of free radicals in biological tissues such as skin. Of these free radicals, the O2–· and particularly the ·OH radical can induce cellular damage including lipid peroxidation. Thus, the use of antioxidants to prevent such damage induced by UV irradiation has received much attention recently. One such antioxidant, which has the potential to be incorporated into sunscreens, is the pineal secretory product melatonin. One of the concerns of using melatonin in sunscreens is its photostability. In the present study, we investigated the photostability of melatonin subjected to UV irradiation. In addition, we used liquid chromatography mass spectrometry (LC-MS) to identify the degradants and we also assessed the ability of the degradants to inhibit O2–· generation as well as lipid peroxidation in rat brain homogenate. The results show that UV irradiation of melatonin (0.1 mg/mL) using a 400-W lamp for 2 hr caused a significant decline of melatonin to 18% of its original concentration after 20 min, with the decline continuing until the melatonin concentration reaches zero at 120 min. The LC-MS results show that the degradants of melatonin are 6-hydroxymelatonin and N1-acetyl-N2-formyl-5-methoxykynurenamine (AFMK). These degradants were able to provide equipotent activity against potassium cyanide (KCN)-induced superoxide generation compared to non-irradiated melatonin. Thus, the study shows that although melatonin is rapidly degraded by UV irradiation, the degradants retain antioxidant activity, making melatonin a likely candidate for inclusion in sunscreens.
Format: computer
Format: online resource
Format: application/pdf
Format: 1 online resource (5 pages)
Format: pdf
Publisher: Wiley Library Online
Language: English
Relation: Journal of Pineal Research
Relation: Maharaj, D.S., Anoopkumar‐Dukie, S., Glass, B.D., Antunes, E.M., Lack, B., Walker, R.B. and Daya, S., 2002. The identification of the UV degradants of melatonin and their ability to scavenge free radicals. Journal of pineal research, 32(4), pp.257-261
Relation: Journal of Pineal Research volume 32 number 4 p.257 2002 0742-3098
Rights: Publisher
Rights: Use of this resource is governed by the terms and conditions of the Wiley Library Online Terms of Use Statement (https://onlinelibrary.wiley.com/terms-and-conditions)
Rights: Closed Access

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