Search for: All records

Abstract Lipid oxidation by reactive oxygen species (ROS) provide several different oxidation products that have been implicated in inflammatory responses. Ground state atomic oxygen [O(³P)] is produced by the photodeoxygenation of certain heterocyclic oxides and has a reactivity that is unique from other ROS. Due to the reactive nature of O(³P), the site of O(³P)‐generation is expected to influence the products in heterogenous solutions or environments. In this work, the oxidation of low‐density lipoprotein (LDL) by lipids with covalently bound O(³P)‐photoprecursors was compared to more hydrophilic O(³P)‐photoprecursors. Lipid oxidation products were quantified after Bligh‐Dyer extraction and pentafluorobenzyl bromide (PFB) derivatization by GC–MS. Unlike the more hydrophilic O(³P)‐photoprecursors, the oxidation of LDL during the irradiation of lipid‐(O³P)‐photoprecursor conjugates showed little quenching by the addition of the O(³P)‐scavenging sodium allyl sulfonate. This indicated that lipophilic O(³P)‐photoprecursors are expected to generate lipid oxidation products where other more hydrophilic O(³P)‐photoprecursors could be quenched by other reactive groups present in solution or the environment. 

Abstract Photodeoxygenation of dibenzothiopheneS‐oxide (DBTO) is believed to produce ground‐state atomic oxygen [O(³P)] in solution. Compared with other reactive oxygen species (ROS), O(³P) is a unique oxidant as it is potent and selective. Derivatives of DBTO have been used as O(³P)‐precursors to oxidize variety of molecules, including plasmid DNA, proteins, lipids, thiols, and other small organic molecules. Unfortunately, the photodeoxygenation of DBTO requires ultraviolet irradiation, which is not an ideal wavelength range for biological systems, and has a low quantum yield of approximately 0.003. In this work, benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide, benzo[b]naphtho[2,1‐d]selenopheneSe‐oxide, dinaphtho[2,3‐b:2’,3’‐d]selenopheneSe‐oxide, and perylo[1,12‐b,c,d]selenopheneSe‐oxide were synthesized, and their ability to utilize visible light for generating O(³P) was interrogated. Benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide produces O(³P) upon irradiation centered at 420 nm. Additionally, benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide, benzo[b]naphtho[2,1‐d]selenopheneSe‐oxide, and dinaphtho[2,3‐b:2’,3’‐d]selenopheneSe‐oxide produce O(³P) when irradiated with UVA light and have quantum yields of photodeoxygenation ranging from 0.009 to 0.33. This work increases the utility of photodeoxygenation by extending the range of wavelengths that can be used to generate O(³P) in solution.