The Inhibitory Effect of Oxibiol on the Process of Protein Modification by Water-Soluble Products of Photo-Oxidative Destruction of Bisretinoid A2E

We have previously shown that the heteroaromatic antioxidant oxibiol (N-acetylcysteinate 6-hydroxy-2-aminobenzothiazole) inhibited the process of fructosylation of serum albumin. The purpose of this study was to elucidate the inhibitory effect of oxibiol on protein modification by photodestruction products of bisretinoid A2E, the main fluorophore of lipofuscin granules of retinal pigment epithelium cells of the human eye. It was found that the water-soluble fraction obtained from A2E-liposomes irradiated with visible light, unlike the water-soluble fraction from nonirradiated A2E-liposomes, significantly modified albumin after a day of incubation at 37°C. Oxibiol at millimolar concentrations effectively inhibited this process. The inhibitory effect of oxibiol was probably based on its antioxidant activity and the ability to competitively interact with reactive aldehydes formed during the photo-oxidative destruction of A2E-cardiolipin liposomes. The acute toxicity of oxibiol in mice with intraperitoneal administration was studied and the values of LD₁₀ and LD₅₀ were determined. The results indicated the promising use of oxibiol in pharmacology for the prevention and treatment of diseases associated with the development of oxidative stress in various fields of medicine, primarily in ophthalmology.