Light and dark peanut meal extracts were prepared by roasting peanuts at 187 °C for 8.6 and 12.7 minutes. The peanuts were then defatted and extracted with a mixture of ethanol-water. An increase of total phenolic compounds was observed, with a significant increase of the absorbance at 294 and 420 nm, the fluorescence intensity as well as the total color differences of extracts due to the development of Maillard reaction. HPL-C analysis revealed the presence of different phenolic compounds in the samples. Moreover, the antioxidant abilities on chelating ability, reducing power and against hydrogen peroxide (H2O2) induced oxidative stress on 158 N oligodendrocyte were explored. Notably, the effect of heating time was found to enhance the antioxidant activity. Likewise, H2O2-induced cell death was significatively reduced and lower levels of malondialdehyde, conjugated diene and carbonylated proteins were observed. These data reinforce the interest for this extract in the prevention of oxidative stress. Highlights: Light and dark peanut meal extracts were prepared by heating peanuts by-products. Roasting decrease sugar and protein contents and increase total phenolic content. Development of Maillard reaction after roasting. Dark peanut meal extract showed enhanced antioxidant activities. Both peanut meal extracts attenuated oxidative stress associated with 100 H2O2.