Extract of Cornus officinalis Protects Keratinocytes from Particulate Matter-induced Oxidative Stress

The skin is one of the large organs in the human body and the most exposed to outdoor contaminants such as particulate matter < 2.5 µm (PM_2.5). Recently, we reported that PM_2.5 induced cellular macromolecule disruption of lipids, proteins, and DNA, via reactive oxygen species, eventually causing cellular apoptosis of human keratinocytes. In this study, the ethanol extract of Cornus officinalis fruit (EECF) showed anti-oxidant effect against PM_2.5-induced cellular oxidative stress. EECF protected cells against PM_2.5-induced DNA damage, lipid peroxidation, and protein carbonylation. PM_2.5 up-regulated intracellular and mitochondrial Ca²⁺ levels excessively, which led to mitochondrial depolarization and cellular apoptosis. However, EECF suppressed the PM_2.5-induced excessive Ca²⁺ accumulation and inhibited apoptosis. The data confirmed that EECF greatly protected human HaCaT keratinocytes from PM_2.5-induced oxidative stress.