Figure 3. Peroxide production by UV-irradiated NHEK cells

H. heterophylla leaf extract protected keratinocytes in a concentration-dependent manner from UV-induced H2O2 production (see Figure 3); 45 min of pretreatment with the extract at 37 µg/mL resulted in a significant 63% reduction of UV-induced H2O2 production (*** : p < 0.001), compared with the untreated control.