In this study, antioxidant activity and total phenolic content of aqueous extract of oak acorn Quercus robur (belongs to fagaceae family) was investigated by using in vitro antioxidant models including total antioxidant capacity, reducing power and metal chelating activity. The total contents of phenol, flavonoid and alkaloid were quantitatively estimated in oak’s acorn and its shell. Result showed that total phenolic, flavonoid, and alkaloid contents were higher in acorn than in its shell. The antioxidant activity of aqueous extract of acorn and its shell were determined according to the phosphomolybdenum method, reducing power and metal chelating was determined by using spectrophotometer. The results were compared to standard compounds such as ascorbic acid, rutin, gallic acid and colchicine. The overall result showed that oak acorn can serve as good sources of bioactive poly phenol in human diet and can be considered as a good candidate for nutritional supplement formulation due to their high concentrations of phenolic compounds, flavonoids, as well as their strong antioxidant activity
