UVC-protective effect of caffeic acid on normal and transformed human skin cells in vitro.

Possible UVC-protective properties of CA, a plant phenolic compound with antioxidant activity, were investigated on human KF1 diploid fibroblast and A431 epidermoid carcinoma cell lines. Cell populations, untreated and treated by antioxidants (CA and alpha-tocopherol), were irradiated by UVC at the wavelength of 254 nm and their proliferation activity was determined by the MTT assay. The results show a strong protective effect of CA at both concentrations used (55.5 and 166.5 microM): a significant increase of proliferation activity after UVC irradiation was detected in both cell populations growing in the presence of CA in comparison with cells in DMEM only. The described protective effect of CA was more obvious in transformed cells than in normal diploid cells. This protective ability is probably based on the antioxidant and scavenging activities of CA, which seems to be more efficient than alpha-tocopherol in protection against the cytotoxic effect caused by UVC irradiation.