TY - JOUR
T1 - Oxidation of squalene by singlet oxygen and free radicals results in different compositions of squalene monohydroperoxide isomers
AU - Shimizu, Naoki
AU - Ito, Junya
AU - Kato, Shunji
AU - Otoki, Yurika
AU - Goto, Masashi
AU - Eitsuka, Takahiro
AU - Miyazawa, Teruo
AU - Nakagawa, Kiyotaka
N1 - Funding Information:
This study was supported in part by JSPS KAKENHI Grant Numbers JP15H04497 and JP16H06637.
Publisher Copyright:
© 2018 The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Oxidation of squalene (SQ) causes a decline in the nutritional value of SQ in foods, as well as an accumulation of SQ oxidation products in skin lipids which lead to adverse skin conditions. However, mechanistic insights as to how SQ is oxidized by different oxidation mechanisms have been limited, and thus effective measures towards the prevention of SQ oxidation have not been identified. In this study, we oxidized SQ by either singlet oxygen oxidation or free radical oxidation, and monitored the formation of the six SQ monohydroperoxide (SQOOH) isomers, the primary oxidation products of SQ, at the isomeric level. While singlet oxygen oxidation of SQ resulted in the formation of similar amounts of the six SQOOH isomers, free radical oxidation of SQ mainly formed two types of isomers, 2-OOH-SQ and 3-OOH-SQ. The addition of β-carotene during singlet oxygen oxidation, and the addition of α-tocopherol during free radical oxidation lead to a dose-dependent decrease in the formation of SQOOH isomers. Such results suggest that the analysis of SQOOH at the isomeric level allows for the determination of the cause of SQ oxidation in various samples, and provides a foothold for future studies concerning the prevention of SQ oxidation.
AB - Oxidation of squalene (SQ) causes a decline in the nutritional value of SQ in foods, as well as an accumulation of SQ oxidation products in skin lipids which lead to adverse skin conditions. However, mechanistic insights as to how SQ is oxidized by different oxidation mechanisms have been limited, and thus effective measures towards the prevention of SQ oxidation have not been identified. In this study, we oxidized SQ by either singlet oxygen oxidation or free radical oxidation, and monitored the formation of the six SQ monohydroperoxide (SQOOH) isomers, the primary oxidation products of SQ, at the isomeric level. While singlet oxygen oxidation of SQ resulted in the formation of similar amounts of the six SQOOH isomers, free radical oxidation of SQ mainly formed two types of isomers, 2-OOH-SQ and 3-OOH-SQ. The addition of β-carotene during singlet oxygen oxidation, and the addition of α-tocopherol during free radical oxidation lead to a dose-dependent decrease in the formation of SQOOH isomers. Such results suggest that the analysis of SQOOH at the isomeric level allows for the determination of the cause of SQ oxidation in various samples, and provides a foothold for future studies concerning the prevention of SQ oxidation.
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U2 - 10.1038/s41598-018-27455-5
DO - 10.1038/s41598-018-27455-5
M3 - Article
C2 - 29904110
AN - SCOPUS:85048740749
SN - 2045-2322
VL - 8
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 9116
ER -