In this study, the antioxidant activity is expressed in terms of
EC50 and ascorbic acid equivalent. High value of ascorbic acid
equivalent, or low value of EC50 means high antioxidant activity. It
is clearly seen that the methanolic extracts (free form of phenolic
compounds) of all rice samples had higher antioxidant activity than
those of alkaline extracts (bound form of phenolic compounds).
In conclusion, the rice samples contained high TPC and TFC,
showed high antioxidant activity. Similar to the Ref. Oki et al.
(2002), pigment rice had higher antioxidant activity than nonpigment
rice. In addition, the brown rice samples contained higher
TPC, TFC and antioxidant activity than their polished form. Table