Oxidation of melatonin by singlet molecular oxygen (O2(1Δg)) produces N1‐acetyl‐N2‐formyl‐5‐methoxykynurenine

Journal of Pineal Research - Tập 35 Số 2 - Trang 131-137 - 2003
Eduardo Alves de Almeida1, Gláucia Regina Martinez, Clécio F. Klitzke, Marisa Helena Gennari de Medeiros, Paolo Di Mascio
1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil

Tóm tắt

Abstract: It has been shown that melatonin exhibits antioxidant properties. Chemical structures of some of the products formed by the interaction of melatonin with reactive oxygen and nitrogen species have been elucidated. Despite some evidence that the reaction of melatonin with singlet molecular oxygen (O2(1Δg)) produces N1‐acetyl‐N2‐formyl‐5‐methoxykynurenine (AFMK), it has not been fully documented. In this investigation, melatonin was oxidized by photosensitization with methylene blue or by a clean chemical source of O2(1Δg), the thermodecomposition of N,N′‐di(2,3‐dihydroxypropyl)‐1,4‐naphtalenedipropanamide (DHPNO2). The resulting product was characterized by high performance liquid chromatography, coupled to electrospray ionization mass spectrometry and also by 1H, 13C and dept135 nuclear magnetic resonance spectroscopy. An isotopically labeled DHPN18O2 was also prepared and used as a chemical source of labeled 18[O2(1Δg)] to unequivocally characterize the end product. The results uncovered by this work confirm the hypothesis that oxidation of melatonin by O2(1Δg) produces AFMK.

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Journal of Pineal Research

Tập 35 Số 2

131-137

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