This research has been conducted on the use of phenolic compounds from the fruit extracts of Toona Sureni as an antioxidant bioactive materials in preventing the oxidation of coconut oil. The study was done in three path ways, i.e. extraction of phenolic compound from the fruits of Toona Sureni, coconut oil extraction, and oil quality measuring by means of determining peroxide value (PV) and free fatty acids (FFA). In oil quality testing, sample was heated at 125 ºC for 3 hours. That sample were analyzed by determining peroxide value (PV) and free fatty acids (FFA). The results showed that the addition of extract to the oil that was heated for 3 hours at temperature of 125 ºC could inhibit the increase of peroxide value and free fatty acids. The inhibiratory of Toona Sureni’s extract to peroxide value was effective at 200 ppm of concentration, 0.96 meq/kg. Antioxidant activity of the extract was expressed effectively by inhibihatory the increase of free fatty acids in addition 150 ppm of extract, 0.19%.