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-Grich red bean on the protection from oxidative damage.