Abstract :Abstract
The mixture of bioactive constituents and their byproducts contained in plant extracts and various natural products produce synergistic effects. But the mechanisms responsible for synergistic antioxidant activity are not explained yet due to the complex nature of the plant extracts. The mechanisms underlying synergistic interactions should be known for the standardization and optimization of mixtures of different synthetic and natural antioxidants and also for the formulation of different natural antioxidants like single extracts or multi- extract preparations which requires quick and reliable analytical methods, evaluation mechanisms and an easy, clear and unbiased method of synergy assessment. The synergistic antioxidative activity of the optimized mixture can more effectively or at lower doses, prevent or treat the various diseases caused by oxidative damage and also protect food from oxidation and microbial contamination thus reducing the side effects caused by the excessive use of synthetic antioxidants.