Reduction of oxidative stress by p-hydroxybenzyl alcohol-containing biodegradable polyoxalate nanoparticulate antioxidant

The large production of reactive oxygen species (ROS) leads to the oxidative stress and the subsequent functional decline of organ systems. p-Hydroxybenzyl alcohol (HBA) is known to play a pivotal protective role against oxidative stress-related diseases. We have developed biodegradable antioxidant copolyoxalate, in which HBA is chemically incorporated into its backbone for the treatment of oxidative stress-related diseases. HBA-incorporated copolyoxalate (HPOX) was designed to possess aromatic peroxalate ester linkages in its backbone and release HBA during its hydrolytic degradation. Peroxalate ester linkages in the backbone reacted with and scavenged hydrogen peroxide, leading the release of HBA in vitro. HBA released from HPOX exerted excellent antioxidant activity, such as inhibition of nitric oxide (NO) production by suppressing iNOS (inducible nitric oxide synthases) expression in lipopolysaccharide (LPS)-activated RAW 264.7 cells. HPOX nanoparticles delivered intranasally significantly reduced pulmonary inflammation and suppressed the iNOS expression. Given their excellent antioxidant and anti-inflammatory activities, we anticipate that HPOX nanoparticles are highly potent for the treatment of oxidative damage-related diseases, such as asthma.