In vitrooxidations of low-density lipoprotein and RAW 264.7 cells with lipophilic O(3P)-precursors

A beneficial property of photogenerated reactive oxygen species (ROS) is the capability of oxidant generation within a specific location or organelle inside a cell. DibenzothiopheneS-oxide (DBTO), which is known to undergo a photodeoxygenation reaction to generate ground state atomic oxygen [O(P-3)] upon irradiation, was functionalized to afford localization within the plasma membrane of cells. The photochemistry, as it relates to oxidant generation, was studied and demonstrated that the functionalizedDBTOderivatives generated O(P-3). Irradiation of these lipophilic O(P-3)-precursors in the presence of LDL and within RAW 264.7 cells afforded several oxidized lipid products (oxLP) in the form of aldehydes. The generation of a 2-hexadecenal (2-HDEA) was markedly increased in irradiations where O(P-3) was putatively produced. The substantial generation of2-HDEAis not known to accompany the production of other ROS. These cellular irradiation experiments demonstrate the potential of inducing oxidation with O(P-3) in cells.