Abstract: Objective: To explore the antioxidant activity of health foods in vivo and in vitro by ORAC (oxygen radical absorbance capacity) fluorometric assay and to carry out correlation analysis. Methods: The antioxidant activities of vitamin C and 3 health foods were evaluated in trolox equivalent antioxidant capacity. Results: A correlation between the in vivo and in vitro antioxidant activities of health foods was observed. The antioxidant activity of samples whose in vitro antioxidant activity was larger than the gavage dose of 25μmol Trolox/kg body weight for mice was determined as positive in mice after oral administration for 30 consecutive days. Conclusion: Under certain conditions, a correlation between the in vivo and in vitro antioxidant activities of health foods determined by ORAC exists, which can be used for speculating the antioxidant activity in vivo of heath foods by ORAC determination in vitro.

Key words: health food, antioxidant activity, oxygen radical absorbance capacity (ORAC) method, in vitro determination, in vivo detetmination