Protective Effect of Spirulina-Derived C-Phycocyanin against Ultraviolet B-Induced Damage in HaCaT Cells

Reactive oxygen species (ROS) overwhelm the antioxidant defense system, induce oxidative stress, and increase matrix metalloproteinase (MMP) expression, resulting in skin aging. Thus, preventing ultraviolet B (UVB)-induced skin damage can attenuate skin aging. Spirulina (a biomass of cyanobacteria, also called blue-green algae) is comprised of prokaryotes, whereas microalgae are eukaryotes and are rich in phycocyanin, a powerful antioxidant. Here, we investigated the photoprotective effects of spirulina-derived C-phycocyanin (C-PC) against UVB radiation using keratinocytes (HaCaT cells). UVB radiation increased MMP-1 and MMP-9 expression but decreased involucrin, filaggrin, and loricrin expression. C-PC showed no toxicity at concentrations of 5-80 μg/mL in terms of HaCaT cell viability. UVB-irradiated HaCaT cells had a 50.8% survival rate, which increased to 80.3% with C-PC treatment. MMP expression increased with UVB treatment, whereas MMP-1 and MMP-9 concentrations decreased with C-PC treatment. UVB reduced involucrin, filaggrin, and loricrin expression in HaCaT cells, but 80 μg/mL C-PC increased their expression by >25%. In the UVB radiation group, dichlorofluorescin diacetate fluorescence intensity in HaCaT cells increased by 81.6% compared with that in the control group, whereas ROS production was reduced by 51.2% and 55.1% upon treatment with 40 and 80 μg/mL C-PC, respectively. C-PC might reduce or prevent skin aging by reducing UVB irradiation-induced skin wrinkles and free radicals.