Skin resistance to UVB-induced oxidative stress and hyperpigmentation by the topical use of Lactobacillus helveticus NS8-fermented milk supernatant.

AIMS

In this study, we investigated the preventive properties of the supernatant of Lactobacillus helveticus NS8-fermented milk (NS8-FS) against UV light-induced skin oxidative damage and hyperpigmentation.

METHODS AND RESULTS

NS8-FS exhibited significant radical scavenging activity in tests with ABST and DPPH scavenging methods, and as well strongly inhibited 3-morpholinosydnonimine (Sin-1)-induced ROS generation in HaCat keratinocytes. Unexpectedly, NS8-FS was found to inhibit melanin production in B16F10 melanoma cells and to exhibit inhibitory effects both to the enzymatic activity of tyrosinase (TYR) and the expression of proteins required for melanin synthesis. In SKH-1 hairless mice, topical application of NS8-FS alleviated UVB-induced skin photodamage, including the improvement of the appearance of epidermal thickness, transepidennal water loss and lipid peroxidation levels. In the tanning guinea pig model, the whitening effect of NS8-FS was demonstrated using Masson-Fontana staining and TYR staining. Furthermore, NS8-FS was shown to stimulate the nuclear translocation and activation of the Nrf2 protein, along with recovery of antioxidant enzyme activities.

CONCLUSION

NS8-FS exhibits the protective capacities against UV light-induced skin oxidative damage and hyperpigmentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings indicate the potential of cell-free fermented products of lactic acid bacteria in topical photoprotection.