20] 3-(4′-methyl- 1′-naphthyl)propionic acid, 1′,4′-endoperoxide for dioxygenation of squalene and for bacterial killing

Abstract

In recent years, considerable interest has been focused on the reaction of singlet oxygen ( 1 O 2 ; l Δ g ) with organic compounds and its toxicity toward living cells. Known 1 O 2 generating systems, such as NaOCI-H 2 O 2 , myeloperoxidase- hydrogen peroxide (H 2 O 2 )-halide ions, and light-photosensitizer-O 2 systems contain reactive oxygen species other than 1 O 2 and often generate free radicals, and therefore such systems cannot serve as pure 1 O 2 generating reactions. In the light of the aforementioned information, Saito et al., synthesized a novel water-soluble naphthalene endoperoxide [3-(4'-methyl-1'-naphthyl) propionic acid, l',4'-endoperoxide; NEPO], producing 1 O 2 thermolytically, not photochemically. However, little is known about the kinetic aspects of NEPO decomposition to produce 1 O 2 in organic solvents or in aqueous media. This chapter discusses the stoichiometry of NEPO thermolysis with quantification of 1 O 2 during incubation of NEPO in an organic or aqueous solution. On the basis of stoichiometric data obtained reactivity of 1 O 2 toward lipids in organic solvents, and its toxicity on two Escherichia coli strains and on human endothelial cells in aqueous media were examined with NEPO as a pure 1 O 2 yielding compound.