Protective Effects of Standardized Extract and Its Active Compound Kirenol Against UVB-induced Photoaging through Inhibition of MAPK/NF-κB Pathways.

Anti-photoaging effects of standardized extract (SGE) and its major active compound kirenol were investigated using Hs68 human dermal fibroblasts and hairless mice, respectively. UVB-irradiated hairless mice that received oral SGE (600 mg/kg/day) showed reduced wrinkle formation and skinfold thickness compared to the UVB-irradiated control. Furthermore, SGE treatment increased the mRNA levels of collagen synthesis genes (COL1A1, COL3A1, COL4A1, and COL7A1) and activated antioxidant enzyme (catalase), while suppressing the matrix metalloproteinases (MMPs; MMP-2, -3, -9, and -13) expression. In Hs68 fibroblasts, kirenol also significantly suppressed the MMPs expression while increasing the expression of COL1A1, COL3A1, and COL7A1. Collectively, our data demonstrate that both SGE and kirenol attenuated UVB-induced photoaging in hairless mice and fibroblasts through inhibition of the mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) pathways, suggesting that SGE has potential to serve as a natural anti-photoaging nutraceutical.