(+)-Usnic acid as a promising candidate for a safe and stable topical photoprotective agent
- Author:
- Galanty A., Popiół J., Paczkowska-Walendowska M., Studzińska-Sroka E., Paśko P., Cielecka-Piontek J., Pękala E. & Podolak I.
- Year:
- 2021
- Journal:
- Molecules
- Pages:
- 26(17): 5224 [11 p.]
- Url:
- https://doi.org/10.3390/molecules26175224
The study aimed to examine whether usnic acid—a lichen compound with UV-absorbing properties—can be considered as a prospective photoprotective agent in cosmetic products. Moreover, a comparison of two usnic acid enantiomers was performed to preselect the more effective compound. To meet this aim, an in vitro model was created, comprising the determination of skin-penetrating properties via skin-PAMPA assay, safety assessment to normal human skin cells (keratinocytes, melanocytes, fibroblasts), and examination of photostability and photoprotective properties. Both enantiomers revealed comparable good skin-penetrating properties. Left-handed usnic acid was slightly more toxic to keratinocytes (IC50 80.82 and 40.12 µg/mL, after 48 and 72 h, respectively) than its right-handed counterpart. The latter enantiomer, in a cosmetic formulation, was characterized by good photoprotective properties and photostability, comparable to the UV filter octocrylene. Perhaps most interestingly, (+)-usnic acid combined with octocrylene in one formulation revealed enhanced photoprotection and photostability. Thus, the strategy can be considered for the potential use of (+)-usnic acid as a UV filter in cosmetic products. Moreover, the proposed model may be useful for the evaluation of candidates for UV filters.
Keywords: usnic acid; photoprotection; normal skin cells; octocrylene.
- Id:
- 33736
- Submitter:
- zdenek
- Post_time:
- Monday, 30 August 2021 11:01