Catechin-7-O-β-d-glucopyranoside scavenges free radicals and protects human B lymphoma BJAB cells on H2O2-mediated oxidative stress

Catechin-7-O-β-d-glucopyranoside (CA-G) was previously isolated from red bean (the seed of Phaseolus calcaratus cv. Roxburgh). This study examined the ability of CA-G to scavenge reactive oxygen species generated by cell-free systems and to protect cells from oxidative stress caused by hydrogen peroxide (H2O2). The mechanism by which CA-G exerts its antioxidant and anti-apoptotic action on H2O2-exposed cells was also investigated. CA-G treatment prevented H2O2-mediated apoptosis and inhibited the formation of single stand breaks in DNA in H2O2-exposed BJAB cells. CA-G suppressed mitochondrial stress and caspase activation caused by H2O2. Mechanistic experiments revealed that the antioxidant mechanism of CA-G on H2O2-mediated oxidative damage was due to the direct scavenging of hydroxyl radicals and/or to the chelation of metal ions that were used to produce hydroxyl radicals from H2O2 via the Fenton reaction. Collectively, these findings suggest beneficial roles of CA-G or CA-G-rich red bean on the protection from oxidative damage.