This study was carried out to investigate the possibility of obtaining some phenolic compounds (as natural antioxidant) from grape seed. The physicochemical properties of the extracted oil, as well as its fatty acid composition were determined. The antioxidant effect of phenolic extract was compared with the synthetic one (TBHQ) by using Rancimate method. Phenolic extract was added to sunflower oil at 0.02, 0.04 and 0.08% and TBHQ was added at 0.02%. The induction period of sunflower oil (control) was 6.07h. and it increased to 9.42, 11.5, 17.68 and 12.8 hours for the previous concentrations respectively. Sunflower oil with these different concentrations of phenolic extract and TBHQ were used for deep-frying of potato up to 18 hours to study the effect of these compounds on the stability of oil after frying. The phenolic extract constituents were identified using HPLC analysis. P. Coumaric was the major phenolic compound (64.99%) followed by O.Coumaric, P.OH-benzoic acid, catechin, pyrogallic, galic acid and protocatechin. The effect of feeding on control fried sunflower oil and fried sunflower oil with the different concentrations of phenolic extract and TBHQ 0.02% on total cholesterol, LDL, HDL, triglyceride, total antioxidant, malondialdehyde, and nitric oxid in albino rats was studied, In addition  the feeding on fried sunflower oil with 0.08% phenolic extract was found  to enhance and improve the liver tissue followed by TBHQ when compared with fried sunflower oil and fried sunflower oil with 0.02, and 0.04% phenolic extract.