Abstract: Eight dietary flavonoids were considered for their variation in activity as antioxidants. Semi-empirical models such as MNDO, AM1, RM1 and PM3; Density functional models at B3LYP energy level with 6-31G* and 6-31G** and moller-plesset perturbation model, MP2 at 6-31G* were used for full optimization of the structures. These methods were used to calculate the parameters such as lipophilicity, ovality, polarizability, vibrational frequency and ultraviolet absorptions which account theoretically for antioxidant potential of the flavonoids. The result of the vibrational frequency showed that MP2/6-31G* compare well with experimental values but could not determine the ultraviolet absorption bands. Myrcetin, of all the flavonoids under study, showed the highest antioxidant activity as well as antigen (stimulates an immune response in the body, especially the production of antibodies).