Yvonne Seel, Monika Guhr, Renate Klöcking, Roland Schubert, Jürgen I. Schoenherr
Proceedings of the 14th International Peat Congress
humic-substances, u937-cells, uv-a-absorption, uv-b-absorption, uv-protective-effect
Theme VI. Balnelogical, medicinal and therapeutical use of peat
Humic acids (HA) known for their antiviral and UV-B protecting effects are considered promising candidates for developing a photoprotective lipstick which should minimize or even prevent the risk of UV-induced herpes recurrences.
In this study, UV/VIS spectra of natural HA, synthetic HA-like substances and other lipstick components were analyzed to find out the most appropriate UV-absorbing ingredients for the product under development. The results show the expected high absorption degree of all HA in the UV-B range, but reveal certain differences in the UV-A range. Moreover, the contribution of matrix components to the total UV-B absorption of the lipstick was proved. The results 24 hours after UV exposition demonstrated significant dose-dependent UV-B protective effects of the tested HA similar to those of p-aminobenzoic acid (PABA) used as UV-B absorbing reference substance.