Rice bran is a co-product from milling process that is usually used for animal feed, and it is also a good source of bioactive compound for human health. This research was conducted to investigate the DPPH radical-scavenging activity and total polyphenol content in methanol extract (MRB), protein isolates (PIRB) and peptide (PRB) derived from Khao Dawk Mali 105 (KDML105) rice bran and Jao Hom Nin rice brans. It was found that MRB, PIRB and PRB derived from Jao Hom Nin rice bran had higher protein content, total polyphenol and antioxidant activity than those obtained from KDML105 rice bran, because the pigment from Jao Hom Nin rice bran was found to be directly correlated to total polyphenol content, an antioxidant. Extracts derived from KDML105 rice bran showed that PRB contained total polyphenol content much higher than PIRB by 14.04 and 1.96 mg GAE/g rice bran extract, respectively. Similarly, extracts which were derived from Jao Hom Nin rice bran had total polyphenol content of 39.90 and 5.05 mg GAE/g rice bran extract in PRB and PIRB, respectively. On the antioxidant activity correlated with total polyphenol content, PRB derived from both KDML105 and Jao Hom Nin rice brans showed more antioxidant activity than PIRB.