Inhibitory Effect of Fractionated Trapa Japonica Extracts on UVB-induced Skin Photoaging

Abstract

Ultraviolet B (UVB) is a primary environmental factor that induces adverse effects on skin such as photoaging, skin burn and cancer. UVB also increases the expression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which converts inactive cortisone to active cortisol in response to a variety of stressors in target tissues. Thus, we have screened new herbal extracts that suppress 11β-HSD1 expression induced by UVB in human dermal fibroblasts. We also investigated whether Trapa japonica (TJ) extract and its fractions inhibit UVB-induced photoaging in Hs68 cells and 3D skin model. Results showed that TJ extract inhibited the increase of 11β-HSD1 expression in UVB-exposed Hs68 cells significantly. TJ extract and its fractions not only inhibited 11β-HSD1 expression, but also suppressed the increase of matrix metalloproteinases 3,9) and proinflammatory cytokines 8) in UVB-irritated Hs68 cells. TJ extract also inhibited MMP-1 expression in UVB-irritated 3D skin model. In addition, TJ extract recovered UVB-induced decreases of epidermal thickness and PCNA-positive cells in 3D skin model. Taken together, these results suggest that TJ extract and its fractions inhibit UVB-induced skin photoaging by interfering with 11β-HSD1 and MMPs.