DNA REPAIR ACTIVATION AND CELL DEATH SUPPRESSION BY PLANT POLYPHENOLS IN KERATINOCYTES EXPOSED TO UV-IRRADIATION.

The 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 the PPs added immediately after UV-C exposure. The efficiency of PPs was lowered in the order: acacetin ≥ silybin > quercetin. It was also studied the influence of PPs on phosphorylation of histones H2AX and the number of single-strand DNA breaks in the nuclei of keratinocytes. Using the comet-assay and gamma H2AX staining followed by fluorescence microscopy it has been established that PPs can reduce DNA damage in the nuclei of keratinocytes exposed to UV-C radiation. It is concluded that the PPs can diminish the destructive effect of UV radiation on the skin cells, activating the process of repairing genetic damage.