Figure 1.

D-limonene reduced H₂O₂-induced cell death in HLECs. (a) HLECs were incubated in 25–800 μM of H₂O₂ for 12, 24, and 48 h. (b) Morphology of HLECs exposed to H₂O₂ (0–800 μM) for 24 h. (c) HLECs are shown to be stained with the nuclear dye Hoechst 33342 (blue)/PI (red) and photographed by a confocal-fluorescence microscope. (d) HLECs were incubated in 62.5–2000 μM of D-limonene for 12, 24, and 48 h. (e) HLECs were pretreated with various concentrations of D-limonene (62.5–2000 μM) for 12 h, 24 h, and 48 h and then incubated in the presence of 100 μM H₂O₂ for 24 h. The results were measured by an MTT assay and expressed as a percentage of the untreated control.