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Useful 1 O 2 ( 1 Δ g ) generator, 3‐(4′‐methyl‐1′‐naphthyl)‐propionic acid, 1′,4′‐endoperoxide (NEPO), for dioxygenation of squalene (a skin surface lipid) in an organic solvent and bacterial killing in aqueous medium
Author(s) -
Nakano Minoru,
Kambayashi Yasuhiro,
Tatsuzawa Hidetaka,
Komiyama Tomoko,
Fujimori Ken
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00822-9
Subject(s) - chemistry , squalene , generator (circuit theory) , stereochemistry , physics , organic chemistry , power (physics) , quantum mechanics
3‐(4′‐Methyl‐1′‐naphthyl)‐propionic acid, 1′,4′‐endoperoxide (NEPO) provides singlet state of oxygen ( 1 O 2 , 1 Δ g ) at 37°C in sodium phosphate buffer (pH 7.2), acetate buffer (pH 4.5), methanol or chloroform, through the retro‐Diels‐Alder reaction. The total amount of 1 O 2 generated by NEPO was calculated using the following equation: [ 1 O 2 ]=[NEPO] 0 [1−exp −kt ], where [ 1 O 2 ], [NEPO] 0 and k are the total amount of 1 O 2 produced during the time t , initial concentration of NEPO and the first‐order reaction rate constant, respectively. When squalene was exposed to 1 O 2 which was generated thermolytically from NEPO, it was oxidized to three hydroperoxides, mono‐, di‐ and tri‐hydroperoxides, in amounts proportional to the dose of NEPO. The oxidizability of squalene was much more extensive compared with unsaturated phospholipids. Additionally, when wild‐type E. coli and lycopene‐producing mutant E. coli were exposed to NEPO‐derived 1 O 2 , there was significant loss of viability of wild‐type E. coli but no significant loss of viability in lycopene‐producing strain, suggesting that lycopene by scavenging 1 O 2 protected E. coli against 1 O 2 toxicity.