Evidence that lipid peroxidation in microsomal membranes of epidermis is associated with generation of hydrogen peroxide and singlet oxygen

Abstract

The role of superoxide, singlet oxygen and hydrogen peroxide in the augumentation of enzymic lipid peroxidation in epidermal microsomes was assessed. Incubation of epidermal microsomes with NADPH or xanthine oxidase-system resulted in significant generation of lipid peroxides as measured by malondialdehyde formation. Epidermal lipid peroxidation was inhibited by catalase and singlet oxygen quenchers, 2,5-dimethylfuran, histidine and β carotene whereas OH − scavengers, benzoate, mannitol and ethyl alcohol had no effect. Superoxide dismutase had no protective effect on lipid peroxidation. Vitamin E and cytochrome c 3+ substantially inhibited the epidermal lipid peroxidation. These studies demonstrate that polyunsaturated lipids of skin microsomes are susceptible to peroxidation. Chemical agents known to protect against the toxic effects of singlet oxygen and hydrogen peroxide inhibited microsomal lipid peroxidation suggesting that these moieties may play a significant role in mediating the reaction.