Lycopene, an acyclic
hydrocarbon, non-
provitamin A
carotenoid, is a potent
antioxidant with well-documented anticancer properties. In this study, we investigated the effects of dietary
lycopene on sub-acute and chronic ultraviolet B (UVB)-induced skin
carcinogenesis in SKH-1 mice. Groups of three mice were fed with a nonsupplemented or 1%
lycopene diet for two weeks before and throughout two weeks of UVB irradiation (30 mJ/cm2 UVB, thrice weekly). The
lycopene diet significantly reduced the formation of
pyrimidine dimers (PDs) and the expression of proliferative cellular
nuclear antigen (
PCNA) in UVB-irradiated skin. Then groups of eighteen mice were each fed with control diet or with a 0.25% or 1% (w/w)
lycopene-supplemented diet for 40 weeks, beginning one week before UVB irradiation (30 mJ/cm2 UVB, thrice weekly for 23 weeks) and continuing after termination of UVB.
Lycopene significantly inhibited the onset and decreased the incidence, multiplicity, and
tumor weights of UVB-induced skin
tumors. UVB-induced epidermal
hyperplasia and
PCNA expression were still remarkably inhibited by dietary
lycopene, even up to 40 weeks. No significant difference in protection was detected between the low and high concentrations of
lycopene. These results demonstrate that dietary
lycopene does protect against UVB-induced epidermal
hyperplasia and
carcinogenesis. J Drugs Dermatol. 2019;18(12):1244-1254.