Effect of (+)-catechin on activation of caspase-3 by H
-induced oxidative stress in fibroblasts. After incubation with serum-free medium for 24 h, fibroblasts were treated for 30 min with 10 μM (+)-catechin and then subjected to oxidative stress induction with 0.1 mM hydrogen peroxide (H2O2). After 1 h, activation of caspase-3 was determined by SDS-PAGE and western blotting analysis using an anti-cleaved caspase-3 antibody. (a) Representative images of western blot analysis for cleaved and total caspase-3. (b) Expression levels of cleaved caspase-3 were normalized to those of total caspase-3. Data are expressed as the mean ± SEM. **P < 0.01.