Cycloartenyl trans-ferulate, a component of the bran byproduct of sake-brewing rice, inhibits mammalian DNA polymerase and suppresses inflammation

•Cycloartenyl trans-ferulate (CAF) was isolated from sake-brewing rice bran.•CAF inhibited the activity of mammalian DNA polymerases of A-, B-, and X-families.•The components of CAF, cycloartenol, and ferulic acid, had no inhibitory activity.•CAF had anti-inflammatory properties, unlike cycloartenol and ferulic acid.•Bran containing CAF could be used in anti-inflammatory foods and/or cosmetics. During the screening of selective DNA polymerase (pol) inhibitors, we isolated cycloartenyl trans-ferulate (CAF), which is a major component of γ-oryzanol, which is a byproduct formed during the production of Japanese rice wine “sake”. CAF selectively inhibited the activity of mammalian A, B, and X pol families, but Y family pols were not affected. CAF did not influence the activities of plant or prokaryotic pols, nor the activity of other DNA metabolic enzymes tested. Individual chemical components of CAF, including cycloartenol (CA) and ferulic acid (FA), did not inhibit pol enzyme activities. CAF suppressed TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation in the mouse ear, but CA and FA did not. The ability to inhibit mammalian pol enzymes in vitro was positively correlated with their propensity to suppress inflammation in vivo. These results suggest that this byproduct formed during the sake-brewing process is useful as an anti-inflammatory agent.