1333 Collagen-derived hydroxyproline-containing cyclic dipeptides inhibits ROS-induced photoaging in UVB-irradiated keratinocytes

Skin photoaging is characterized by wrinkles, laxity, and dryness cumulatively caused sunlight exposure. One of the major contributors to skin reactive oxygen species (ROS), which trigger inflammatory response collagen degradation. Cyclic dipeptides (2,5-diketopiperazines) present in various foods microorganisms are reported have antioxidant activity. We previously developed a unique hydrolysate enriched with hydroxyproline (Hyp)-containing cyclic dipeptides, cyclo(X-Hyp), digestion ginger protease subsequent heat treatment. Here, we evaluated inhibitory effects cyclo(X-Hyp) heat-treated ginger-degraded (H-GDCH) on ROS-induced UVB-irradiated normal human epidermal keratinocytes (NHEK). NHEK were cultured addition 0.05 mg/mL synthetic peptides or 1 hydrolysates for 30 min (ROS) 2 days (others) after UVB irradiation at 20 mJ/cm2. Cyclo(X-Hyp) H-GDCH showed significant reductions ROS level compared control, scavenging ability was superior corresponding linear (X-Hyp) Pro-containing [cyclo(X-Pro)]. NF-κB activation, MAPK phosphorylation, matrix metalloproteinase expression, downstream induction, inhibited H-GDCH, suggesting anti-inflammatory anti-collagen degradation collagen-specific dipeptides. In vitro permeability experiments using Franz-type diffusion cell that penetrated dermatomed high efficiency up 10% 24 hours, while most liner X-Hyp did not. Our results indicate excellent potential development anti-photoaging cosmetics.