DNA Repair Activation and Cell Death Suppression by Plant Polyphenols in Keratinocytes Exposed to Ultraviolet Irradiation

This work investigated effects of plant polyphenolic compounds (PPs) on responses of cultured human HaCaT keratinocytes to ultraviolet radiation in the C range (UV-C). The experimental data obtained indicate a cytoprotective effect of PPs added immediately after UV-C exposure. The efficiency of PPs was lowered in the following order: acacetin ≥ silybin > quercetin. The influence of PPs on phosphorylation of histone H2AX and the number of single-strand DNA breaks in the nuclei of keratinocytes were also studied. Using the comet assay and γH2AX staining, followed by fluorescence microscopy, it has been established that PPs can reduce DNA damage in the nuclei of keratinocytes exposed to UV-C. It is concluded that PPs can diminish the destructive effect of UV radiation on skin cells, activating the process of repairing genetic damage.