Effect of Hydrolyzed Royal Jelly on Rough Skin (in vitro)

Abstract

Rough skin, which is characterized by lower skin surface water content and higher transepidermal water loss, is similar to the symptom of dry skin. In general, rough skin is reproduced by the topical treatment of an anionic surfactant, sodium lauryl sulfate (SLS). After skin contact, SLS impairs the stratum corneum and exerts a direct toxic effect on the keratinocytes. On the other hand, royal jelly, which has some benefits on the skin such as an increase of collagen production and reduction of melanin production, is widely used as a cosmetic substance. In the study, we evaluated some potentials of the hydrolyzed protein in royal jelly (HR) focusing on the improvement possibility for rough skin using the responsiveness of HaCaT keratinocytes exposed to SLS. HR showed an increase of cell tolerance, and suppressed Interleukin (IL)-1α and IL-8 secretion against exposure to SLS. In addition, HR gave a reduction of the intracellular reactive oxygen species level elevated by SLS. HR showed an increase of cell viability after exposure to hydrogen peroxide. HR showed an increase of intracellular catalase and glutathione. Gathering these results, HR has a potential to improve/prevent rough skin formation through the stimulation of intracellular defenses against oxidative stress.